linux/kernel/trace/trace.c

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ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/*
* ring buffer based function tracer
*
* Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
*
* Originally taken from the RT patch by:
* Arnaldo Carvalho de Melo <acme@redhat.com>
*
* Based on code from the latency_tracer, that is:
* Copyright (C) 2004-2006 Ingo Molnar
* Copyright (C) 2004 Nadia Yvette Chambers
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
*/
#include <linux/ring_buffer.h>
#include <generated/utsrelease.h>
#include <linux/stacktrace.h>
#include <linux/writeback.h>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
#include <linux/notifier.h>
#include <linux/irqflags.h>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#include <linux/debugfs.h>
#include <linux/tracefs.h>
#include <linux/pagemap.h>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#include <linux/hardirq.h>
#include <linux/linkage.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#include <linux/ftrace.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/splice.h>
#include <linux/kdebug.h>
#include <linux/string.h>
#include <linux/mount.h>
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
#include <linux/rwsem.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 09:04:11 +01:00
#include <linux/slab.h>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/nmi.h>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#include <linux/fs.h>
#include <linux/sched/rt.h>
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#include "trace.h"
#include "trace_output.h"
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/*
* On boot up, the ring buffer is set to the minimum size, so that
* we do not waste memory on systems that are not using tracing.
*/
bool ring_buffer_expanded;
/*
* We need to change this state when a selftest is running.
* A selftest will lurk into the ring-buffer to count the
* entries inserted during the selftest although some concurrent
* insertions into the ring-buffer such as trace_printk could occurred
* at the same time, giving false positive or negative results.
*/
static bool __read_mostly tracing_selftest_running;
/*
* If a tracer is running, we do not want to run SELFTEST.
*/
bool __read_mostly tracing_selftest_disabled;
/* Pipe tracepoints to printk */
struct trace_iterator *tracepoint_print_iter;
int tracepoint_printk;
/* For tracers that don't implement custom flags */
static struct tracer_opt dummy_tracer_opt[] = {
{ }
};
static int
dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
{
return 0;
}
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
/*
* To prevent the comm cache from being overwritten when no
* tracing is active, only save the comm when a trace event
* occurred.
*/
static DEFINE_PER_CPU(bool, trace_cmdline_save);
/*
* Kill all tracing for good (never come back).
* It is initialized to 1 but will turn to zero if the initialization
* of the tracer is successful. But that is the only place that sets
* this back to zero.
*/
static int tracing_disabled = 1;
cpumask_var_t __read_mostly tracing_buffer_mask;
/*
* ftrace_dump_on_oops - variable to dump ftrace buffer on oops
*
* If there is an oops (or kernel panic) and the ftrace_dump_on_oops
* is set, then ftrace_dump is called. This will output the contents
* of the ftrace buffers to the console. This is very useful for
* capturing traces that lead to crashes and outputing it to a
* serial console.
*
* It is default off, but you can enable it with either specifying
* "ftrace_dump_on_oops" in the kernel command line, or setting
* /proc/sys/kernel/ftrace_dump_on_oops
* Set 1 if you want to dump buffers of all CPUs
* Set 2 if you want to dump the buffer of the CPU that triggered oops
*/
enum ftrace_dump_mode ftrace_dump_on_oops;
/* When set, tracing will stop when a WARN*() is hit */
int __disable_trace_on_warning;
#ifdef CONFIG_TRACE_ENUM_MAP_FILE
/* Map of enums to their values, for "enum_map" file */
struct trace_enum_map_head {
struct module *mod;
unsigned long length;
};
union trace_enum_map_item;
struct trace_enum_map_tail {
/*
* "end" is first and points to NULL as it must be different
* than "mod" or "enum_string"
*/
union trace_enum_map_item *next;
const char *end; /* points to NULL */
};
static DEFINE_MUTEX(trace_enum_mutex);
/*
* The trace_enum_maps are saved in an array with two extra elements,
* one at the beginning, and one at the end. The beginning item contains
* the count of the saved maps (head.length), and the module they
* belong to if not built in (head.mod). The ending item contains a
* pointer to the next array of saved enum_map items.
*/
union trace_enum_map_item {
struct trace_enum_map map;
struct trace_enum_map_head head;
struct trace_enum_map_tail tail;
};
static union trace_enum_map_item *trace_enum_maps;
#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
static int tracing_set_tracer(struct trace_array *tr, const char *buf);
#define MAX_TRACER_SIZE 100
static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
static char *default_bootup_tracer;
static bool allocate_snapshot;
static int __init set_cmdline_ftrace(char *str)
{
strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
default_bootup_tracer = bootup_tracer_buf;
/* We are using ftrace early, expand it */
ring_buffer_expanded = true;
return 1;
}
__setup("ftrace=", set_cmdline_ftrace);
static int __init set_ftrace_dump_on_oops(char *str)
{
if (*str++ != '=' || !*str) {
ftrace_dump_on_oops = DUMP_ALL;
return 1;
}
if (!strcmp("orig_cpu", str)) {
ftrace_dump_on_oops = DUMP_ORIG;
return 1;
}
return 0;
}
__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
static int __init stop_trace_on_warning(char *str)
{
if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
__disable_trace_on_warning = 1;
return 1;
}
__setup("traceoff_on_warning", stop_trace_on_warning);
static int __init boot_alloc_snapshot(char *str)
{
allocate_snapshot = true;
/* We also need the main ring buffer expanded */
ring_buffer_expanded = true;
return 1;
}
__setup("alloc_snapshot", boot_alloc_snapshot);
static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
static int __init set_trace_boot_options(char *str)
{
strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
return 0;
}
__setup("trace_options=", set_trace_boot_options);
static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
static char *trace_boot_clock __initdata;
static int __init set_trace_boot_clock(char *str)
{
strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
trace_boot_clock = trace_boot_clock_buf;
return 0;
}
__setup("trace_clock=", set_trace_boot_clock);
static int __init set_tracepoint_printk(char *str)
{
if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
tracepoint_printk = 1;
return 1;
}
__setup("tp_printk", set_tracepoint_printk);
unsigned long long ns2usecs(cycle_t nsec)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
nsec += 500;
do_div(nsec, 1000);
return nsec;
}
/* trace_flags holds trace_options default values */
#define TRACE_DEFAULT_FLAGS \
(FUNCTION_DEFAULT_FLAGS | \
TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
/* trace_options that are only supported by global_trace */
#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
/* trace_flags that are default zero for instances */
#define ZEROED_TRACE_FLAGS \
TRACE_ITER_EVENT_FORK
/*
* The global_trace is the descriptor that holds the tracing
* buffers for the live tracing. For each CPU, it contains
* a link list of pages that will store trace entries. The
* page descriptor of the pages in the memory is used to hold
* the link list by linking the lru item in the page descriptor
* to each of the pages in the buffer per CPU.
*
* For each active CPU there is a data field that holds the
* pages for the buffer for that CPU. Each CPU has the same number
* of pages allocated for its buffer.
*/
static struct trace_array global_trace = {
.trace_flags = TRACE_DEFAULT_FLAGS,
};
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
LIST_HEAD(ftrace_trace_arrays);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int trace_array_get(struct trace_array *this_tr)
{
struct trace_array *tr;
int ret = -ENODEV;
mutex_lock(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (tr == this_tr) {
tr->ref++;
ret = 0;
break;
}
}
mutex_unlock(&trace_types_lock);
return ret;
}
static void __trace_array_put(struct trace_array *this_tr)
{
WARN_ON(!this_tr->ref);
this_tr->ref--;
}
void trace_array_put(struct trace_array *this_tr)
{
mutex_lock(&trace_types_lock);
__trace_array_put(this_tr);
mutex_unlock(&trace_types_lock);
}
int call_filter_check_discard(struct trace_event_call *call, void *rec,
tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:34:17 +02:00
struct ring_buffer *buffer,
struct ring_buffer_event *event)
{
if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
!filter_match_preds(call->filter, rec)) {
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
__trace_event_discard_commit(buffer, event);
tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:34:17 +02:00
return 1;
}
return 0;
}
void trace_free_pid_list(struct trace_pid_list *pid_list)
{
vfree(pid_list->pids);
kfree(pid_list);
}
/**
* trace_find_filtered_pid - check if a pid exists in a filtered_pid list
* @filtered_pids: The list of pids to check
* @search_pid: The PID to find in @filtered_pids
*
* Returns true if @search_pid is fonud in @filtered_pids, and false otherwis.
*/
bool
trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
{
/*
* If pid_max changed after filtered_pids was created, we
* by default ignore all pids greater than the previous pid_max.
*/
if (search_pid >= filtered_pids->pid_max)
return false;
return test_bit(search_pid, filtered_pids->pids);
}
/**
* trace_ignore_this_task - should a task be ignored for tracing
* @filtered_pids: The list of pids to check
* @task: The task that should be ignored if not filtered
*
* Checks if @task should be traced or not from @filtered_pids.
* Returns true if @task should *NOT* be traced.
* Returns false if @task should be traced.
*/
bool
trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
{
/*
* Return false, because if filtered_pids does not exist,
* all pids are good to trace.
*/
if (!filtered_pids)
return false;
return !trace_find_filtered_pid(filtered_pids, task->pid);
}
/**
* trace_pid_filter_add_remove - Add or remove a task from a pid_list
* @pid_list: The list to modify
* @self: The current task for fork or NULL for exit
* @task: The task to add or remove
*
* If adding a task, if @self is defined, the task is only added if @self
* is also included in @pid_list. This happens on fork and tasks should
* only be added when the parent is listed. If @self is NULL, then the
* @task pid will be removed from the list, which would happen on exit
* of a task.
*/
void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
struct task_struct *self,
struct task_struct *task)
{
if (!pid_list)
return;
/* For forks, we only add if the forking task is listed */
if (self) {
if (!trace_find_filtered_pid(pid_list, self->pid))
return;
}
/* Sorry, but we don't support pid_max changing after setting */
if (task->pid >= pid_list->pid_max)
return;
/* "self" is set for forks, and NULL for exits */
if (self)
set_bit(task->pid, pid_list->pids);
else
clear_bit(task->pid, pid_list->pids);
}
/**
* trace_pid_next - Used for seq_file to get to the next pid of a pid_list
* @pid_list: The pid list to show
* @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
* @pos: The position of the file
*
* This is used by the seq_file "next" operation to iterate the pids
* listed in a trace_pid_list structure.
*
* Returns the pid+1 as we want to display pid of zero, but NULL would
* stop the iteration.
*/
void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
{
unsigned long pid = (unsigned long)v;
(*pos)++;
/* pid already is +1 of the actual prevous bit */
pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
/* Return pid + 1 to allow zero to be represented */
if (pid < pid_list->pid_max)
return (void *)(pid + 1);
return NULL;
}
/**
* trace_pid_start - Used for seq_file to start reading pid lists
* @pid_list: The pid list to show
* @pos: The position of the file
*
* This is used by seq_file "start" operation to start the iteration
* of listing pids.
*
* Returns the pid+1 as we want to display pid of zero, but NULL would
* stop the iteration.
*/
void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
{
unsigned long pid;
loff_t l = 0;
pid = find_first_bit(pid_list->pids, pid_list->pid_max);
if (pid >= pid_list->pid_max)
return NULL;
/* Return pid + 1 so that zero can be the exit value */
for (pid++; pid && l < *pos;
pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
;
return (void *)pid;
}
/**
* trace_pid_show - show the current pid in seq_file processing
* @m: The seq_file structure to write into
* @v: A void pointer of the pid (+1) value to display
*
* Can be directly used by seq_file operations to display the current
* pid value.
*/
int trace_pid_show(struct seq_file *m, void *v)
{
unsigned long pid = (unsigned long)v - 1;
seq_printf(m, "%lu\n", pid);
return 0;
}
/* 128 should be much more than enough */
#define PID_BUF_SIZE 127
int trace_pid_write(struct trace_pid_list *filtered_pids,
struct trace_pid_list **new_pid_list,
const char __user *ubuf, size_t cnt)
{
struct trace_pid_list *pid_list;
struct trace_parser parser;
unsigned long val;
int nr_pids = 0;
ssize_t read = 0;
ssize_t ret = 0;
loff_t pos;
pid_t pid;
if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
return -ENOMEM;
/*
* Always recreate a new array. The write is an all or nothing
* operation. Always create a new array when adding new pids by
* the user. If the operation fails, then the current list is
* not modified.
*/
pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
if (!pid_list)
return -ENOMEM;
pid_list->pid_max = READ_ONCE(pid_max);
/* Only truncating will shrink pid_max */
if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
pid_list->pid_max = filtered_pids->pid_max;
pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
if (!pid_list->pids) {
kfree(pid_list);
return -ENOMEM;
}
if (filtered_pids) {
/* copy the current bits to the new max */
for_each_set_bit(pid, filtered_pids->pids,
filtered_pids->pid_max) {
set_bit(pid, pid_list->pids);
nr_pids++;
}
}
while (cnt > 0) {
pos = 0;
ret = trace_get_user(&parser, ubuf, cnt, &pos);
if (ret < 0 || !trace_parser_loaded(&parser))
break;
read += ret;
ubuf += ret;
cnt -= ret;
parser.buffer[parser.idx] = 0;
ret = -EINVAL;
if (kstrtoul(parser.buffer, 0, &val))
break;
if (val >= pid_list->pid_max)
break;
pid = (pid_t)val;
set_bit(pid, pid_list->pids);
nr_pids++;
trace_parser_clear(&parser);
ret = 0;
}
trace_parser_put(&parser);
if (ret < 0) {
trace_free_pid_list(pid_list);
return ret;
}
if (!nr_pids) {
/* Cleared the list of pids */
trace_free_pid_list(pid_list);
read = ret;
pid_list = NULL;
}
*new_pid_list = pid_list;
return read;
}
static cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
{
u64 ts;
/* Early boot up does not have a buffer yet */
if (!buf->buffer)
return trace_clock_local();
ts = ring_buffer_time_stamp(buf->buffer, cpu);
ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
return ts;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
cycle_t ftrace_now(int cpu)
{
return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
}
/**
* tracing_is_enabled - Show if global_trace has been disabled
*
* Shows if the global trace has been enabled or not. It uses the
* mirror flag "buffer_disabled" to be used in fast paths such as for
* the irqsoff tracer. But it may be inaccurate due to races. If you
* need to know the accurate state, use tracing_is_on() which is a little
* slower, but accurate.
*/
ftrace: restructure tracing start/stop infrastructure Impact: change where tracing is started up and stopped Currently, when a new tracer is selected via echo'ing a tracer name into the current_tracer file, the startup is only done if tracing_enabled is set to one. If tracing_enabled is changed to zero (by echo'ing 0 into the tracing_enabled file) a full shutdown is performed. The full startup and shutdown of a tracer can be expensive and the user can lose out traces when echo'ing in 0 to the tracing_enabled file, because the process takes too long. There can also be places that the user would like to start and stop the tracer several times and doing the full startup and shutdown of a tracer might be too expensive. This patch performs the full startup and shutdown when a tracer is selected. It also adds a way to do a quick start or stop of a tracer. The quick version is just a flag that prevents the tracing from taking place, but the overhead of the code is still there. For example, the startup of a tracer may enable tracepoints, or enable the function tracer. The stop and start will just set a flag to have the tracer ignore the calls when the tracepoint or function trace is called. The overhead of the tracer may still be present when the tracer is stopped, but no tracing will occur. Setting the tracer to the 'nop' tracer (or any other tracer) will perform the shutdown of the tracer which will disable the tracepoint or disable the function tracer. The tracing_enabled file will simply start or stop tracing. This change is all internal. The end result for the user should be the same as before. If tracing_enabled is not set, no trace will happen. If tracing_enabled is set, then the trace will happen. The tracing_enabled variable is static between tracers. Enabling tracing_enabled and going to another tracer will keep tracing_enabled enabled. Same is true with disabling tracing_enabled. This patch will now provide a fast start/stop method to the users for enabling or disabling tracing. Note: There were two methods to the struct tracer that were never used: The methods start and stop. These were to be used as a hook to the reading of the trace output, but ended up not being necessary. These two methods are now used to enable the start and stop of each tracer, in case the tracer needs to do more than just not write into the buffer. For example, the irqsoff tracer must stop recording max latencies when tracing is stopped. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-05 22:05:44 +01:00
int tracing_is_enabled(void)
{
/*
* For quick access (irqsoff uses this in fast path), just
* return the mirror variable of the state of the ring buffer.
* It's a little racy, but we don't really care.
*/
smp_rmb();
return !global_trace.buffer_disabled;
ftrace: restructure tracing start/stop infrastructure Impact: change where tracing is started up and stopped Currently, when a new tracer is selected via echo'ing a tracer name into the current_tracer file, the startup is only done if tracing_enabled is set to one. If tracing_enabled is changed to zero (by echo'ing 0 into the tracing_enabled file) a full shutdown is performed. The full startup and shutdown of a tracer can be expensive and the user can lose out traces when echo'ing in 0 to the tracing_enabled file, because the process takes too long. There can also be places that the user would like to start and stop the tracer several times and doing the full startup and shutdown of a tracer might be too expensive. This patch performs the full startup and shutdown when a tracer is selected. It also adds a way to do a quick start or stop of a tracer. The quick version is just a flag that prevents the tracing from taking place, but the overhead of the code is still there. For example, the startup of a tracer may enable tracepoints, or enable the function tracer. The stop and start will just set a flag to have the tracer ignore the calls when the tracepoint or function trace is called. The overhead of the tracer may still be present when the tracer is stopped, but no tracing will occur. Setting the tracer to the 'nop' tracer (or any other tracer) will perform the shutdown of the tracer which will disable the tracepoint or disable the function tracer. The tracing_enabled file will simply start or stop tracing. This change is all internal. The end result for the user should be the same as before. If tracing_enabled is not set, no trace will happen. If tracing_enabled is set, then the trace will happen. The tracing_enabled variable is static between tracers. Enabling tracing_enabled and going to another tracer will keep tracing_enabled enabled. Same is true with disabling tracing_enabled. This patch will now provide a fast start/stop method to the users for enabling or disabling tracing. Note: There were two methods to the struct tracer that were never used: The methods start and stop. These were to be used as a hook to the reading of the trace output, but ended up not being necessary. These two methods are now used to enable the start and stop of each tracer, in case the tracer needs to do more than just not write into the buffer. For example, the irqsoff tracer must stop recording max latencies when tracing is stopped. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-05 22:05:44 +01:00
}
/*
* trace_buf_size is the size in bytes that is allocated
* for a buffer. Note, the number of bytes is always rounded
* to page size.
*
* This number is purposely set to a low number of 16384.
* If the dump on oops happens, it will be much appreciated
* to not have to wait for all that output. Anyway this can be
* boot time and run time configurable.
*/
#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/* trace_types holds a link list of available tracers. */
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static struct tracer *trace_types __read_mostly;
/*
* trace_types_lock is used to protect the trace_types list.
*/
DEFINE_MUTEX(trace_types_lock);
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
/*
* serialize the access of the ring buffer
*
* ring buffer serializes readers, but it is low level protection.
* The validity of the events (which returns by ring_buffer_peek() ..etc)
* are not protected by ring buffer.
*
* The content of events may become garbage if we allow other process consumes
* these events concurrently:
* A) the page of the consumed events may become a normal page
* (not reader page) in ring buffer, and this page will be rewrited
* by events producer.
* B) The page of the consumed events may become a page for splice_read,
* and this page will be returned to system.
*
* These primitives allow multi process access to different cpu ring buffer
* concurrently.
*
* These primitives don't distinguish read-only and read-consume access.
* Multi read-only access are also serialized.
*/
#ifdef CONFIG_SMP
static DECLARE_RWSEM(all_cpu_access_lock);
static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
static inline void trace_access_lock(int cpu)
{
if (cpu == RING_BUFFER_ALL_CPUS) {
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
/* gain it for accessing the whole ring buffer. */
down_write(&all_cpu_access_lock);
} else {
/* gain it for accessing a cpu ring buffer. */
/* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
down_read(&all_cpu_access_lock);
/* Secondly block other access to this @cpu ring buffer. */
mutex_lock(&per_cpu(cpu_access_lock, cpu));
}
}
static inline void trace_access_unlock(int cpu)
{
if (cpu == RING_BUFFER_ALL_CPUS) {
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
up_write(&all_cpu_access_lock);
} else {
mutex_unlock(&per_cpu(cpu_access_lock, cpu));
up_read(&all_cpu_access_lock);
}
}
static inline void trace_access_lock_init(void)
{
int cpu;
for_each_possible_cpu(cpu)
mutex_init(&per_cpu(cpu_access_lock, cpu));
}
#else
static DEFINE_MUTEX(access_lock);
static inline void trace_access_lock(int cpu)
{
(void)cpu;
mutex_lock(&access_lock);
}
static inline void trace_access_unlock(int cpu)
{
(void)cpu;
mutex_unlock(&access_lock);
}
static inline void trace_access_lock_init(void)
{
}
#endif
#ifdef CONFIG_STACKTRACE
static void __ftrace_trace_stack(struct ring_buffer *buffer,
unsigned long flags,
int skip, int pc, struct pt_regs *regs);
static inline void ftrace_trace_stack(struct trace_array *tr,
struct ring_buffer *buffer,
unsigned long flags,
int skip, int pc, struct pt_regs *regs);
#else
static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
unsigned long flags,
int skip, int pc, struct pt_regs *regs)
{
}
static inline void ftrace_trace_stack(struct trace_array *tr,
struct ring_buffer *buffer,
unsigned long flags,
int skip, int pc, struct pt_regs *regs)
{
}
#endif
static void tracer_tracing_on(struct trace_array *tr)
{
if (tr->trace_buffer.buffer)
ring_buffer_record_on(tr->trace_buffer.buffer);
/*
* This flag is looked at when buffers haven't been allocated
* yet, or by some tracers (like irqsoff), that just want to
* know if the ring buffer has been disabled, but it can handle
* races of where it gets disabled but we still do a record.
* As the check is in the fast path of the tracers, it is more
* important to be fast than accurate.
*/
tr->buffer_disabled = 0;
/* Make the flag seen by readers */
smp_wmb();
}
/**
* tracing_on - enable tracing buffers
*
* This function enables tracing buffers that may have been
* disabled with tracing_off.
*/
void tracing_on(void)
{
tracer_tracing_on(&global_trace);
}
EXPORT_SYMBOL_GPL(tracing_on);
/**
* __trace_puts - write a constant string into the trace buffer.
* @ip: The address of the caller
* @str: The constant string to write
* @size: The size of the string.
*/
int __trace_puts(unsigned long ip, const char *str, int size)
{
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct print_entry *entry;
unsigned long irq_flags;
int alloc;
int pc;
if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
return 0;
pc = preempt_count();
if (unlikely(tracing_selftest_running || tracing_disabled))
return 0;
alloc = sizeof(*entry) + size + 2; /* possible \n added */
local_save_flags(irq_flags);
buffer = global_trace.trace_buffer.buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
irq_flags, pc);
if (!event)
return 0;
entry = ring_buffer_event_data(event);
entry->ip = ip;
memcpy(&entry->buf, str, size);
/* Add a newline if necessary */
if (entry->buf[size - 1] != '\n') {
entry->buf[size] = '\n';
entry->buf[size + 1] = '\0';
} else
entry->buf[size] = '\0';
__buffer_unlock_commit(buffer, event);
ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
return size;
}
EXPORT_SYMBOL_GPL(__trace_puts);
/**
* __trace_bputs - write the pointer to a constant string into trace buffer
* @ip: The address of the caller
* @str: The constant string to write to the buffer to
*/
int __trace_bputs(unsigned long ip, const char *str)
{
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct bputs_entry *entry;
unsigned long irq_flags;
int size = sizeof(struct bputs_entry);
int pc;
if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
return 0;
pc = preempt_count();
if (unlikely(tracing_selftest_running || tracing_disabled))
return 0;
local_save_flags(irq_flags);
buffer = global_trace.trace_buffer.buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
irq_flags, pc);
if (!event)
return 0;
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->str = str;
__buffer_unlock_commit(buffer, event);
ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
return 1;
}
EXPORT_SYMBOL_GPL(__trace_bputs);
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
#ifdef CONFIG_TRACER_SNAPSHOT
/**
* trace_snapshot - take a snapshot of the current buffer.
*
* This causes a swap between the snapshot buffer and the current live
* tracing buffer. You can use this to take snapshots of the live
* trace when some condition is triggered, but continue to trace.
*
* Note, make sure to allocate the snapshot with either
* a tracing_snapshot_alloc(), or by doing it manually
* with: echo 1 > /sys/kernel/debug/tracing/snapshot
*
* If the snapshot buffer is not allocated, it will stop tracing.
* Basically making a permanent snapshot.
*/
void tracing_snapshot(void)
{
struct trace_array *tr = &global_trace;
struct tracer *tracer = tr->current_trace;
unsigned long flags;
if (in_nmi()) {
internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
internal_trace_puts("*** snapshot is being ignored ***\n");
return;
}
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
if (!tr->allocated_snapshot) {
internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
internal_trace_puts("*** stopping trace here! ***\n");
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
tracing_off();
return;
}
/* Note, snapshot can not be used when the tracer uses it */
if (tracer->use_max_tr) {
internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
return;
}
local_irq_save(flags);
update_max_tr(tr, current, smp_processor_id());
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(tracing_snapshot);
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
struct trace_buffer *size_buf, int cpu_id);
static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
static int alloc_snapshot(struct trace_array *tr)
{
int ret;
if (!tr->allocated_snapshot) {
/* allocate spare buffer */
ret = resize_buffer_duplicate_size(&tr->max_buffer,
&tr->trace_buffer, RING_BUFFER_ALL_CPUS);
if (ret < 0)
return ret;
tr->allocated_snapshot = true;
}
return 0;
}
static void free_snapshot(struct trace_array *tr)
{
/*
* We don't free the ring buffer. instead, resize it because
* The max_tr ring buffer has some state (e.g. ring->clock) and
* we want preserve it.
*/
ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
set_buffer_entries(&tr->max_buffer, 1);
tracing_reset_online_cpus(&tr->max_buffer);
tr->allocated_snapshot = false;
}
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
tracing: Add 'snapshot' event trigger command Add 'snapshot' event_command. snapshot event triggers are added by the user via this command in a similar way and using practically the same syntax as the analogous 'snapshot' ftrace function command, but instead of writing to the set_ftrace_filter file, the snapshot event trigger is written to the per-event 'trigger' files: echo 'snapshot' > .../somesys/someevent/trigger The above command will turn on snapshots for someevent i.e. whenever someevent is hit, a snapshot will be done. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'snapshot:N' > .../somesys/someevent/trigger Where N is the number of times the command will be invoked. The above command will snapshot N times for someevent i.e. whenever someevent is hit N times, a snapshot will be done. Also adds a new tracing_alloc_snapshot() function - the existing tracing_snapshot_alloc() function is a special version of tracing_snapshot() that also does the snapshot allocation - the snapshot triggers would like to be able to do just the allocation but not take a snapshot; the existing tracing_snapshot_alloc() in turn now also calls tracing_alloc_snapshot() underneath to do that allocation. Link: http://lkml.kernel.org/r/c9524dd07ce01f9dcbd59011290e0a8d5b47d7ad.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> [ fix up from kbuild test robot <fengguang.wu@intel.com report ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:59:26 +02:00
/**
* tracing_alloc_snapshot - allocate snapshot buffer.
*
* This only allocates the snapshot buffer if it isn't already
* allocated - it doesn't also take a snapshot.
*
* This is meant to be used in cases where the snapshot buffer needs
* to be set up for events that can't sleep but need to be able to
* trigger a snapshot.
*/
int tracing_alloc_snapshot(void)
{
struct trace_array *tr = &global_trace;
int ret;
ret = alloc_snapshot(tr);
WARN_ON(ret < 0);
return ret;
}
EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
/**
* trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
*
* This is similar to trace_snapshot(), but it will allocate the
* snapshot buffer if it isn't already allocated. Use this only
* where it is safe to sleep, as the allocation may sleep.
*
* This causes a swap between the snapshot buffer and the current live
* tracing buffer. You can use this to take snapshots of the live
* trace when some condition is triggered, but continue to trace.
*/
void tracing_snapshot_alloc(void)
{
int ret;
tracing: Add 'snapshot' event trigger command Add 'snapshot' event_command. snapshot event triggers are added by the user via this command in a similar way and using practically the same syntax as the analogous 'snapshot' ftrace function command, but instead of writing to the set_ftrace_filter file, the snapshot event trigger is written to the per-event 'trigger' files: echo 'snapshot' > .../somesys/someevent/trigger The above command will turn on snapshots for someevent i.e. whenever someevent is hit, a snapshot will be done. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'snapshot:N' > .../somesys/someevent/trigger Where N is the number of times the command will be invoked. The above command will snapshot N times for someevent i.e. whenever someevent is hit N times, a snapshot will be done. Also adds a new tracing_alloc_snapshot() function - the existing tracing_snapshot_alloc() function is a special version of tracing_snapshot() that also does the snapshot allocation - the snapshot triggers would like to be able to do just the allocation but not take a snapshot; the existing tracing_snapshot_alloc() in turn now also calls tracing_alloc_snapshot() underneath to do that allocation. Link: http://lkml.kernel.org/r/c9524dd07ce01f9dcbd59011290e0a8d5b47d7ad.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> [ fix up from kbuild test robot <fengguang.wu@intel.com report ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:59:26 +02:00
ret = tracing_alloc_snapshot();
if (ret < 0)
return;
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
tracing_snapshot();
}
EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
#else
void tracing_snapshot(void)
{
WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
}
EXPORT_SYMBOL_GPL(tracing_snapshot);
tracing: Add 'snapshot' event trigger command Add 'snapshot' event_command. snapshot event triggers are added by the user via this command in a similar way and using practically the same syntax as the analogous 'snapshot' ftrace function command, but instead of writing to the set_ftrace_filter file, the snapshot event trigger is written to the per-event 'trigger' files: echo 'snapshot' > .../somesys/someevent/trigger The above command will turn on snapshots for someevent i.e. whenever someevent is hit, a snapshot will be done. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'snapshot:N' > .../somesys/someevent/trigger Where N is the number of times the command will be invoked. The above command will snapshot N times for someevent i.e. whenever someevent is hit N times, a snapshot will be done. Also adds a new tracing_alloc_snapshot() function - the existing tracing_snapshot_alloc() function is a special version of tracing_snapshot() that also does the snapshot allocation - the snapshot triggers would like to be able to do just the allocation but not take a snapshot; the existing tracing_snapshot_alloc() in turn now also calls tracing_alloc_snapshot() underneath to do that allocation. Link: http://lkml.kernel.org/r/c9524dd07ce01f9dcbd59011290e0a8d5b47d7ad.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> [ fix up from kbuild test robot <fengguang.wu@intel.com report ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:59:26 +02:00
int tracing_alloc_snapshot(void)
{
WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
return -ENODEV;
}
EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
void tracing_snapshot_alloc(void)
{
/* Give warning */
tracing_snapshot();
}
EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
tracing: Add internal tracing_snapshot() functions The new snapshot feature is quite handy. It's a way for the user to take advantage of the spare buffer that, until then, only the latency tracers used to "snapshot" the buffer when it hit a max latency. Now users can trigger a "snapshot" manually when some condition is hit in a program. But a snapshot currently can not be triggered by a condition inside the kernel. With the addition of tracing_snapshot() and tracing_snapshot_alloc(), snapshots can now be taking when a condition is hit, and the developer wants to snapshot the case without stopping the trace. Note, any snapshot will overwrite the old one, so take care in how this is done. These new functions are to be used like tracing_on(), tracing_off() and trace_printk() are. That is, they should never be called in the mainline Linux kernel. They are solely for the purpose of debugging. The tracing_snapshot() will not allocate a buffer, but it is safe to be called from any context (except NMIs). But if a snapshot buffer isn't allocated when it is called, it will write to the live buffer, complaining about the lack of a snapshot buffer, and then stop tracing (giving you the "permanent snapshot"). tracing_snapshot_alloc() will allocate the snapshot buffer if it was not already allocated and then take the snapshot. This routine *may sleep*, and must be called from context that can sleep. The allocation is done with GFP_KERNEL and not atomic. If you need a snapshot in an atomic context, say in early boot, then it is best to call the tracing_snapshot_alloc() before then, where it will allocate the buffer, and then you can use the tracing_snapshot() anywhere you want and still get snapshots. Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-07 03:45:37 +01:00
#endif /* CONFIG_TRACER_SNAPSHOT */
static void tracer_tracing_off(struct trace_array *tr)
{
if (tr->trace_buffer.buffer)
ring_buffer_record_off(tr->trace_buffer.buffer);
/*
* This flag is looked at when buffers haven't been allocated
* yet, or by some tracers (like irqsoff), that just want to
* know if the ring buffer has been disabled, but it can handle
* races of where it gets disabled but we still do a record.
* As the check is in the fast path of the tracers, it is more
* important to be fast than accurate.
*/
tr->buffer_disabled = 1;
/* Make the flag seen by readers */
smp_wmb();
}
/**
* tracing_off - turn off tracing buffers
*
* This function stops the tracing buffers from recording data.
* It does not disable any overhead the tracers themselves may
* be causing. This function simply causes all recording to
* the ring buffers to fail.
*/
void tracing_off(void)
{
tracer_tracing_off(&global_trace);
}
EXPORT_SYMBOL_GPL(tracing_off);
void disable_trace_on_warning(void)
{
if (__disable_trace_on_warning)
tracing_off();
}
/**
* tracer_tracing_is_on - show real state of ring buffer enabled
* @tr : the trace array to know if ring buffer is enabled
*
* Shows real state of the ring buffer if it is enabled or not.
*/
int tracer_tracing_is_on(struct trace_array *tr)
{
if (tr->trace_buffer.buffer)
return ring_buffer_record_is_on(tr->trace_buffer.buffer);
return !tr->buffer_disabled;
}
/**
* tracing_is_on - show state of ring buffers enabled
*/
int tracing_is_on(void)
{
return tracer_tracing_is_on(&global_trace);
}
EXPORT_SYMBOL_GPL(tracing_is_on);
static int __init set_buf_size(char *str)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
unsigned long buf_size;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (!str)
return 0;
buf_size = memparse(str, &str);
/* nr_entries can not be zero */
if (buf_size == 0)
return 0;
trace_buf_size = buf_size;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return 1;
}
__setup("trace_buf_size=", set_buf_size);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
function-graph: Add tracing_thresh support to function_graph tracer Add support for tracing_thresh to the function_graph tracer. This version of this feature isolates the checks into new entry and return functions, to avoid adding more conditional code into the main function_graph paths. When the tracing_thresh is set and the function graph tracer is enabled, only the functions that took longer than the time in microseconds that was set in tracing_thresh are recorded. To do this efficiently, only the function exits are recorded: [tracing]# echo 100 > tracing_thresh [tracing]# echo function_graph > current_tracer [tracing]# cat trace # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 1) ! 119.214 us | } /* smp_apic_timer_interrupt */ 1) <========== | 0) ! 101.527 us | } /* __rcu_process_callbacks */ 0) ! 126.461 us | } /* rcu_process_callbacks */ 0) ! 145.111 us | } /* __do_softirq */ 0) ! 149.667 us | } /* do_softirq */ 0) ! 168.817 us | } /* irq_exit */ 0) ! 248.254 us | } /* smp_apic_timer_interrupt */ Also, add support for specifying tracing_thresh on the kernel command line. When used like so: "tracing_thresh=200 ftrace=function_graph" this can be used to analyse system startup. It is important to disable tracing soon after boot, in order to avoid losing the trace data. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Tim Bird <tim.bird@am.sony.com> LKML-Reference: <4B87098B.4040308@am.sony.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-02-26 00:36:43 +01:00
static int __init set_tracing_thresh(char *str)
{
unsigned long threshold;
function-graph: Add tracing_thresh support to function_graph tracer Add support for tracing_thresh to the function_graph tracer. This version of this feature isolates the checks into new entry and return functions, to avoid adding more conditional code into the main function_graph paths. When the tracing_thresh is set and the function graph tracer is enabled, only the functions that took longer than the time in microseconds that was set in tracing_thresh are recorded. To do this efficiently, only the function exits are recorded: [tracing]# echo 100 > tracing_thresh [tracing]# echo function_graph > current_tracer [tracing]# cat trace # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 1) ! 119.214 us | } /* smp_apic_timer_interrupt */ 1) <========== | 0) ! 101.527 us | } /* __rcu_process_callbacks */ 0) ! 126.461 us | } /* rcu_process_callbacks */ 0) ! 145.111 us | } /* __do_softirq */ 0) ! 149.667 us | } /* do_softirq */ 0) ! 168.817 us | } /* irq_exit */ 0) ! 248.254 us | } /* smp_apic_timer_interrupt */ Also, add support for specifying tracing_thresh on the kernel command line. When used like so: "tracing_thresh=200 ftrace=function_graph" this can be used to analyse system startup. It is important to disable tracing soon after boot, in order to avoid losing the trace data. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Tim Bird <tim.bird@am.sony.com> LKML-Reference: <4B87098B.4040308@am.sony.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-02-26 00:36:43 +01:00
int ret;
if (!str)
return 0;
ret = kstrtoul(str, 0, &threshold);
function-graph: Add tracing_thresh support to function_graph tracer Add support for tracing_thresh to the function_graph tracer. This version of this feature isolates the checks into new entry and return functions, to avoid adding more conditional code into the main function_graph paths. When the tracing_thresh is set and the function graph tracer is enabled, only the functions that took longer than the time in microseconds that was set in tracing_thresh are recorded. To do this efficiently, only the function exits are recorded: [tracing]# echo 100 > tracing_thresh [tracing]# echo function_graph > current_tracer [tracing]# cat trace # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 1) ! 119.214 us | } /* smp_apic_timer_interrupt */ 1) <========== | 0) ! 101.527 us | } /* __rcu_process_callbacks */ 0) ! 126.461 us | } /* rcu_process_callbacks */ 0) ! 145.111 us | } /* __do_softirq */ 0) ! 149.667 us | } /* do_softirq */ 0) ! 168.817 us | } /* irq_exit */ 0) ! 248.254 us | } /* smp_apic_timer_interrupt */ Also, add support for specifying tracing_thresh on the kernel command line. When used like so: "tracing_thresh=200 ftrace=function_graph" this can be used to analyse system startup. It is important to disable tracing soon after boot, in order to avoid losing the trace data. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Tim Bird <tim.bird@am.sony.com> LKML-Reference: <4B87098B.4040308@am.sony.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-02-26 00:36:43 +01:00
if (ret < 0)
return 0;
tracing_thresh = threshold * 1000;
function-graph: Add tracing_thresh support to function_graph tracer Add support for tracing_thresh to the function_graph tracer. This version of this feature isolates the checks into new entry and return functions, to avoid adding more conditional code into the main function_graph paths. When the tracing_thresh is set and the function graph tracer is enabled, only the functions that took longer than the time in microseconds that was set in tracing_thresh are recorded. To do this efficiently, only the function exits are recorded: [tracing]# echo 100 > tracing_thresh [tracing]# echo function_graph > current_tracer [tracing]# cat trace # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 1) ! 119.214 us | } /* smp_apic_timer_interrupt */ 1) <========== | 0) ! 101.527 us | } /* __rcu_process_callbacks */ 0) ! 126.461 us | } /* rcu_process_callbacks */ 0) ! 145.111 us | } /* __do_softirq */ 0) ! 149.667 us | } /* do_softirq */ 0) ! 168.817 us | } /* irq_exit */ 0) ! 248.254 us | } /* smp_apic_timer_interrupt */ Also, add support for specifying tracing_thresh on the kernel command line. When used like so: "tracing_thresh=200 ftrace=function_graph" this can be used to analyse system startup. It is important to disable tracing soon after boot, in order to avoid losing the trace data. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Tim Bird <tim.bird@am.sony.com> LKML-Reference: <4B87098B.4040308@am.sony.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-02-26 00:36:43 +01:00
return 1;
}
__setup("tracing_thresh=", set_tracing_thresh);
unsigned long nsecs_to_usecs(unsigned long nsecs)
{
return nsecs / 1000;
}
tracing: Use TRACE_FLAGS macro to keep enums and strings matched Use a cute little macro trick to keep the names of the trace flags file guaranteed to match the corresponding masks. The macro TRACE_FLAGS is defined as a serious of enum names followed by the string name of the file that matches it. For example: #define TRACE_FLAGS \ C(PRINT_PARENT, "print-parent"), \ C(SYM_OFFSET, "sym-offset"), \ C(SYM_ADDR, "sym-addr"), \ C(VERBOSE, "verbose"), Now we can define the following: #undef C #define C(a, b) TRACE_ITER_##a##_BIT enum trace_iterator_bits { TRACE_FLAGS }; The above creates: enum trace_iterator_bits { TRACE_ITER_PRINT_PARENT_BIT, TRACE_ITER_SYM_OFFSET_BIT, TRACE_ITER_SYM_ADDR_BIT, TRACE_ITER_VERBOSE_BIT, }; Then we can redefine C as: #undef C #define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT) enum trace_iterator_flags { TRACE_FLAGS }; Which creates: enum trace_iterator_flags { TRACE_ITER_PRINT_PARENT = (1 << TRACE_ITER_PRINT_PARENT_BIT), TRACE_ITER_SYM_OFFSET = (1 << TRACE_ITER_SYM_OFFSET_BIT), TRACE_ITER_SYM_ADDR = (1 << TRACE_ITER_SYM_ADDR_BIT), TRACE_ITER_VERBOSE = (1 << TRACE_ITER_VERBOSE_BIT), }; Then finally we can create the list of file names: #undef C #define C(a, b) b static const char *trace_options[] = { TRACE_FLAGS NULL }; Which creates: static const char *trace_options[] = { "print-parent", "sym-offset", "sym-addr", "verbose", NULL }; The importance of this is that the strings match the bit index. trace_options[TRACE_ITER_SYM_ADDR_BIT] == "sym-addr" Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 15:43:30 +02:00
/*
* TRACE_FLAGS is defined as a tuple matching bit masks with strings.
* It uses C(a, b) where 'a' is the enum name and 'b' is the string that
* matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
* of strings in the order that the enums were defined.
*/
#undef C
#define C(a, b) b
/* These must match the bit postions in trace_iterator_flags */
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static const char *trace_options[] = {
tracing: Use TRACE_FLAGS macro to keep enums and strings matched Use a cute little macro trick to keep the names of the trace flags file guaranteed to match the corresponding masks. The macro TRACE_FLAGS is defined as a serious of enum names followed by the string name of the file that matches it. For example: #define TRACE_FLAGS \ C(PRINT_PARENT, "print-parent"), \ C(SYM_OFFSET, "sym-offset"), \ C(SYM_ADDR, "sym-addr"), \ C(VERBOSE, "verbose"), Now we can define the following: #undef C #define C(a, b) TRACE_ITER_##a##_BIT enum trace_iterator_bits { TRACE_FLAGS }; The above creates: enum trace_iterator_bits { TRACE_ITER_PRINT_PARENT_BIT, TRACE_ITER_SYM_OFFSET_BIT, TRACE_ITER_SYM_ADDR_BIT, TRACE_ITER_VERBOSE_BIT, }; Then we can redefine C as: #undef C #define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT) enum trace_iterator_flags { TRACE_FLAGS }; Which creates: enum trace_iterator_flags { TRACE_ITER_PRINT_PARENT = (1 << TRACE_ITER_PRINT_PARENT_BIT), TRACE_ITER_SYM_OFFSET = (1 << TRACE_ITER_SYM_OFFSET_BIT), TRACE_ITER_SYM_ADDR = (1 << TRACE_ITER_SYM_ADDR_BIT), TRACE_ITER_VERBOSE = (1 << TRACE_ITER_VERBOSE_BIT), }; Then finally we can create the list of file names: #undef C #define C(a, b) b static const char *trace_options[] = { TRACE_FLAGS NULL }; Which creates: static const char *trace_options[] = { "print-parent", "sym-offset", "sym-addr", "verbose", NULL }; The importance of this is that the strings match the bit index. trace_options[TRACE_ITER_SYM_ADDR_BIT] == "sym-addr" Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 15:43:30 +02:00
TRACE_FLAGS
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
NULL
};
static struct {
u64 (*func)(void);
const char *name;
tracing: Format non-nanosec times from tsc clock without a decimal point. With the addition of the "tsc" clock, formatting timestamps to look like fractional seconds is misleading. Mark clocks as either in nanoseconds or not, and format non-nanosecond timestamps as decimal integers. Tested: $ cd /sys/kernel/debug/tracing/ $ cat trace_clock [local] global tsc $ echo sched_switch > set_event $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ cat trace <idle>-0 [000] 6330.555552: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 [000] 6330.555628: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo 1 > options/latency-format $ cat trace <idle>-0 0 4104553247us+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 0 4104553322us+: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo tsc > trace_clock $ cat trace $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ echo 0 > options/latency-format $ cat trace <idle>-0 [000] 16490053398357: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 [000] 16490053588518: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... echo 1 > options/latency-format $ cat trace <idle>-0 0 91557653238+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 0 91557843399+: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... v2: Move arch-specific bits out of generic code. v4: Fix x86_32 build due to 64-bit division. Google-Bug-Id: 6980623 Link: http://lkml.kernel.org/r/1352837903-32191-2-git-send-email-dhsharp@google.com Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: David Sharp <dhsharp@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-13 21:18:22 +01:00
int in_ns; /* is this clock in nanoseconds? */
} trace_clocks[] = {
{ trace_clock_local, "local", 1 },
{ trace_clock_global, "global", 1 },
{ trace_clock_counter, "counter", 0 },
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer and time updates from Thomas Gleixner: "A rather large update of timers, timekeeping & co - Core timekeeping code is year-2038 safe now for 32bit machines. Now we just need to fix all in kernel users and the gazillion of user space interfaces which rely on timespec/timeval :) - Better cache layout for the timekeeping internal data structures. - Proper nanosecond based interfaces for in kernel users. - Tree wide cleanup of code which wants nanoseconds but does hoops and loops to convert back and forth from timespecs. Some of it definitely belongs into the ugly code museum. - Consolidation of the timekeeping interface zoo. - A fast NMI safe accessor to clock monotonic for tracing. This is a long standing request to support correlated user/kernel space traces. With proper NTP frequency correction it's also suitable for correlation of traces accross separate machines. - Checkpoint/restart support for timerfd. - A few NOHZ[_FULL] improvements in the [hr]timer code. - Code move from kernel to kernel/time of all time* related code. - New clocksource/event drivers from the ARM universe. I'm really impressed that despite an architected timer in the newer chips SoC manufacturers insist on inventing new and differently broken SoC specific timers. [ Ed. "Impressed"? I don't think that word means what you think it means ] - Another round of code move from arch to drivers. Looks like most of the legacy mess in ARM regarding timers is sorted out except for a few obnoxious strongholds. - The usual updates and fixlets all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits) timekeeping: Fixup typo in update_vsyscall_old definition clocksource: document some basic timekeeping concepts timekeeping: Use cached ntp_tick_length when accumulating error timekeeping: Rework frequency adjustments to work better w/ nohz timekeeping: Minor fixup for timespec64->timespec assignment ftrace: Provide trace clocks monotonic timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC seqcount: Add raw_write_seqcount_latch() seqcount: Provide raw_read_seqcount() timekeeping: Use tk_read_base as argument for timekeeping_get_ns() timekeeping: Create struct tk_read_base and use it in struct timekeeper timekeeping: Restructure the timekeeper some more clocksource: Get rid of cycle_last clocksource: Move cycle_last validation to core code clocksource: Make delta calculation a function wireless: ath9k: Get rid of timespec conversions drm: vmwgfx: Use nsec based interfaces drm: i915: Use nsec based interfaces timekeeping: Provide ktime_get_raw() hangcheck-timer: Use ktime_get_ns() ...
2014-08-06 02:46:42 +02:00
{ trace_clock_jiffies, "uptime", 0 },
{ trace_clock, "perf", 1 },
{ ktime_get_mono_fast_ns, "mono", 1 },
ftrace: Provide trace clock monotonic raw Expose the NMI safe accessor to the monotonic raw clock to the tracer. The mono clock was added with commit 1b3e5c0936046e7e023149ddc8946d21c2ea20eb. The advantage of the monotonic raw clock is that it will advance more constantly than the monotonic clock. Imagine someone is trying to optimize a particular program to reduce instructions executed for a given workload while minimizing the effect on runtime. Also suppose that NTP is running and potentially making larger adjustments to the monotonic clock. If NTP is adjusting the monotonic clock to advance more rapidly, the program will appear to use fewer instructions per second but run longer than if the monotonic raw clock had been used. The total number of instructions observed would be the same regardless of the clock source used, but how it's attributed to time would be affected. Conversely if NTP is adjusting the monotonic clock to advance more slowly, the program will appear to use more instructions per second but run more quickly. Of course there are many sources that can cause jitter in performance measurements on modern processors, but let's remove NTP from the list. The monotonic raw clock can also be useful for tracing early boot, e.g. when debugging issues with NTP. Link: http://lkml.kernel.org/r/20150508143037.GB1276@dreric01-Precision-T1650 Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Drew Richardson <drew.richardson@arm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-05-08 16:30:39 +02:00
{ ktime_get_raw_fast_ns, "mono_raw", 1 },
ARCH_TRACE_CLOCKS
};
/*
* trace_parser_get_init - gets the buffer for trace parser
*/
int trace_parser_get_init(struct trace_parser *parser, int size)
{
memset(parser, 0, sizeof(*parser));
parser->buffer = kmalloc(size, GFP_KERNEL);
if (!parser->buffer)
return 1;
parser->size = size;
return 0;
}
/*
* trace_parser_put - frees the buffer for trace parser
*/
void trace_parser_put(struct trace_parser *parser)
{
kfree(parser->buffer);
}
/*
* trace_get_user - reads the user input string separated by space
* (matched by isspace(ch))
*
* For each string found the 'struct trace_parser' is updated,
* and the function returns.
*
* Returns number of bytes read.
*
* See kernel/trace/trace.h for 'struct trace_parser' details.
*/
int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char ch;
size_t read = 0;
ssize_t ret;
if (!*ppos)
trace_parser_clear(parser);
ret = get_user(ch, ubuf++);
if (ret)
goto out;
read++;
cnt--;
/*
* The parser is not finished with the last write,
* continue reading the user input without skipping spaces.
*/
if (!parser->cont) {
/* skip white space */
while (cnt && isspace(ch)) {
ret = get_user(ch, ubuf++);
if (ret)
goto out;
read++;
cnt--;
}
/* only spaces were written */
if (isspace(ch)) {
*ppos += read;
ret = read;
goto out;
}
parser->idx = 0;
}
/* read the non-space input */
while (cnt && !isspace(ch)) {
if (parser->idx < parser->size - 1)
parser->buffer[parser->idx++] = ch;
else {
ret = -EINVAL;
goto out;
}
ret = get_user(ch, ubuf++);
if (ret)
goto out;
read++;
cnt--;
}
/* We either got finished input or we have to wait for another call. */
if (isspace(ch)) {
parser->buffer[parser->idx] = 0;
parser->cont = false;
tracing: Fix potential out-of-bounds in trace_get_user() Andrey reported the following report: ERROR: AddressSanitizer: heap-buffer-overflow on address ffff8800359c99f3 ffff8800359c99f3 is located 0 bytes to the right of 243-byte region [ffff8800359c9900, ffff8800359c99f3) Accessed by thread T13003: #0 ffffffff810dd2da (asan_report_error+0x32a/0x440) #1 ffffffff810dc6b0 (asan_check_region+0x30/0x40) #2 ffffffff810dd4d3 (__tsan_write1+0x13/0x20) #3 ffffffff811cd19e (ftrace_regex_release+0x1be/0x260) #4 ffffffff812a1065 (__fput+0x155/0x360) #5 ffffffff812a12de (____fput+0x1e/0x30) #6 ffffffff8111708d (task_work_run+0x10d/0x140) #7 ffffffff810ea043 (do_exit+0x433/0x11f0) #8 ffffffff810eaee4 (do_group_exit+0x84/0x130) #9 ffffffff810eafb1 (SyS_exit_group+0x21/0x30) #10 ffffffff81928782 (system_call_fastpath+0x16/0x1b) Allocated by thread T5167: #0 ffffffff810dc778 (asan_slab_alloc+0x48/0xc0) #1 ffffffff8128337c (__kmalloc+0xbc/0x500) #2 ffffffff811d9d54 (trace_parser_get_init+0x34/0x90) #3 ffffffff811cd7b3 (ftrace_regex_open+0x83/0x2e0) #4 ffffffff811cda7d (ftrace_filter_open+0x2d/0x40) #5 ffffffff8129b4ff (do_dentry_open+0x32f/0x430) #6 ffffffff8129b668 (finish_open+0x68/0xa0) #7 ffffffff812b66ac (do_last+0xb8c/0x1710) #8 ffffffff812b7350 (path_openat+0x120/0xb50) #9 ffffffff812b8884 (do_filp_open+0x54/0xb0) #10 ffffffff8129d36c (do_sys_open+0x1ac/0x2c0) #11 ffffffff8129d4b7 (SyS_open+0x37/0x50) #12 ffffffff81928782 (system_call_fastpath+0x16/0x1b) Shadow bytes around the buggy address: ffff8800359c9700: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd ffff8800359c9780: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa ffff8800359c9800: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9880: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>ffff8800359c9980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[03]fb ffff8800359c9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9b00: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00 ffff8800359c9b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8800359c9c00: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap redzone: fa Heap kmalloc redzone: fb Freed heap region: fd Shadow gap: fe The out-of-bounds access happens on 'parser->buffer[parser->idx] = 0;' Although the crash happened in ftrace_regex_open() the real bug occurred in trace_get_user() where there's an incrementation to parser->idx without a check against the size. The way it is triggered is if userspace sends in 128 characters (EVENT_BUF_SIZE + 1), the loop that reads the last character stores it and then breaks out because there is no more characters. Then the last character is read to determine what to do next, and the index is incremented without checking size. Then the caller of trace_get_user() usually nulls out the last character with a zero, but since the index is equal to the size, it writes a nul character after the allocated space, which can corrupt memory. Luckily, only root user has write access to this file. Link: http://lkml.kernel.org/r/20131009222323.04fd1a0d@gandalf.local.home Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-10 04:23:23 +02:00
} else if (parser->idx < parser->size - 1) {
parser->cont = true;
parser->buffer[parser->idx++] = ch;
tracing: Fix potential out-of-bounds in trace_get_user() Andrey reported the following report: ERROR: AddressSanitizer: heap-buffer-overflow on address ffff8800359c99f3 ffff8800359c99f3 is located 0 bytes to the right of 243-byte region [ffff8800359c9900, ffff8800359c99f3) Accessed by thread T13003: #0 ffffffff810dd2da (asan_report_error+0x32a/0x440) #1 ffffffff810dc6b0 (asan_check_region+0x30/0x40) #2 ffffffff810dd4d3 (__tsan_write1+0x13/0x20) #3 ffffffff811cd19e (ftrace_regex_release+0x1be/0x260) #4 ffffffff812a1065 (__fput+0x155/0x360) #5 ffffffff812a12de (____fput+0x1e/0x30) #6 ffffffff8111708d (task_work_run+0x10d/0x140) #7 ffffffff810ea043 (do_exit+0x433/0x11f0) #8 ffffffff810eaee4 (do_group_exit+0x84/0x130) #9 ffffffff810eafb1 (SyS_exit_group+0x21/0x30) #10 ffffffff81928782 (system_call_fastpath+0x16/0x1b) Allocated by thread T5167: #0 ffffffff810dc778 (asan_slab_alloc+0x48/0xc0) #1 ffffffff8128337c (__kmalloc+0xbc/0x500) #2 ffffffff811d9d54 (trace_parser_get_init+0x34/0x90) #3 ffffffff811cd7b3 (ftrace_regex_open+0x83/0x2e0) #4 ffffffff811cda7d (ftrace_filter_open+0x2d/0x40) #5 ffffffff8129b4ff (do_dentry_open+0x32f/0x430) #6 ffffffff8129b668 (finish_open+0x68/0xa0) #7 ffffffff812b66ac (do_last+0xb8c/0x1710) #8 ffffffff812b7350 (path_openat+0x120/0xb50) #9 ffffffff812b8884 (do_filp_open+0x54/0xb0) #10 ffffffff8129d36c (do_sys_open+0x1ac/0x2c0) #11 ffffffff8129d4b7 (SyS_open+0x37/0x50) #12 ffffffff81928782 (system_call_fastpath+0x16/0x1b) Shadow bytes around the buggy address: ffff8800359c9700: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd ffff8800359c9780: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa ffff8800359c9800: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9880: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>ffff8800359c9980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[03]fb ffff8800359c9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9b00: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00 ffff8800359c9b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8800359c9c00: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap redzone: fa Heap kmalloc redzone: fb Freed heap region: fd Shadow gap: fe The out-of-bounds access happens on 'parser->buffer[parser->idx] = 0;' Although the crash happened in ftrace_regex_open() the real bug occurred in trace_get_user() where there's an incrementation to parser->idx without a check against the size. The way it is triggered is if userspace sends in 128 characters (EVENT_BUF_SIZE + 1), the loop that reads the last character stores it and then breaks out because there is no more characters. Then the last character is read to determine what to do next, and the index is incremented without checking size. Then the caller of trace_get_user() usually nulls out the last character with a zero, but since the index is equal to the size, it writes a nul character after the allocated space, which can corrupt memory. Luckily, only root user has write access to this file. Link: http://lkml.kernel.org/r/20131009222323.04fd1a0d@gandalf.local.home Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-10 04:23:23 +02:00
} else {
ret = -EINVAL;
goto out;
}
*ppos += read;
ret = read;
out:
return ret;
}
/* TODO add a seq_buf_to_buffer() */
static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;
if (trace_seq_used(s) <= s->seq.readpos)
return -EBUSY;
len = trace_seq_used(s) - s->seq.readpos;
if (cnt > len)
cnt = len;
memcpy(buf, s->buffer + s->seq.readpos, cnt);
s->seq.readpos += cnt;
return cnt;
}
function-graph: Add tracing_thresh support to function_graph tracer Add support for tracing_thresh to the function_graph tracer. This version of this feature isolates the checks into new entry and return functions, to avoid adding more conditional code into the main function_graph paths. When the tracing_thresh is set and the function graph tracer is enabled, only the functions that took longer than the time in microseconds that was set in tracing_thresh are recorded. To do this efficiently, only the function exits are recorded: [tracing]# echo 100 > tracing_thresh [tracing]# echo function_graph > current_tracer [tracing]# cat trace # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 1) ! 119.214 us | } /* smp_apic_timer_interrupt */ 1) <========== | 0) ! 101.527 us | } /* __rcu_process_callbacks */ 0) ! 126.461 us | } /* rcu_process_callbacks */ 0) ! 145.111 us | } /* __do_softirq */ 0) ! 149.667 us | } /* do_softirq */ 0) ! 168.817 us | } /* irq_exit */ 0) ! 248.254 us | } /* smp_apic_timer_interrupt */ Also, add support for specifying tracing_thresh on the kernel command line. When used like so: "tracing_thresh=200 ftrace=function_graph" this can be used to analyse system startup. It is important to disable tracing soon after boot, in order to avoid losing the trace data. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Tim Bird <tim.bird@am.sony.com> LKML-Reference: <4B87098B.4040308@am.sony.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-02-26 00:36:43 +01:00
unsigned long __read_mostly tracing_thresh;
#ifdef CONFIG_TRACER_MAX_TRACE
/*
* Copy the new maximum trace into the separate maximum-trace
* structure. (this way the maximum trace is permanently saved,
* for later retrieval via /sys/kernel/debug/tracing/latency_trace)
*/
static void
__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
struct trace_buffer *trace_buf = &tr->trace_buffer;
struct trace_buffer *max_buf = &tr->max_buffer;
struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
max_buf->cpu = cpu;
max_buf->time_start = data->preempt_timestamp;
max_data->saved_latency = tr->max_latency;
max_data->critical_start = data->critical_start;
max_data->critical_end = data->critical_end;
memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
max_data->pid = tsk->pid;
tracing: Use current_uid() for critical time tracing The irqsoff tracer records the max time that interrupts are disabled. There are hooks in the assembly code that calls back into the tracer when interrupts are disabled or enabled. When they are enabled, the tracer checks if the amount of time they were disabled is larger than the previous recorded max interrupts off time. If it is, it creates a snapshot of the currently running trace to store where the last largest interrupts off time was held and how it happened. During testing, this RCU lockdep dump appeared: [ 1257.829021] =============================== [ 1257.829021] [ INFO: suspicious RCU usage. ] [ 1257.829021] 3.10.0-rc1-test+ #171 Tainted: G W [ 1257.829021] ------------------------------- [ 1257.829021] /home/rostedt/work/git/linux-trace.git/include/linux/rcupdate.h:780 rcu_read_lock() used illegally while idle! [ 1257.829021] [ 1257.829021] other info that might help us debug this: [ 1257.829021] [ 1257.829021] [ 1257.829021] RCU used illegally from idle CPU! [ 1257.829021] rcu_scheduler_active = 1, debug_locks = 0 [ 1257.829021] RCU used illegally from extended quiescent state! [ 1257.829021] 2 locks held by trace-cmd/4831: [ 1257.829021] #0: (max_trace_lock){......}, at: [<ffffffff810e2b77>] stop_critical_timing+0x1a3/0x209 [ 1257.829021] #1: (rcu_read_lock){.+.+..}, at: [<ffffffff810dae5a>] __update_max_tr+0x88/0x1ee [ 1257.829021] [ 1257.829021] stack backtrace: [ 1257.829021] CPU: 3 PID: 4831 Comm: trace-cmd Tainted: G W 3.10.0-rc1-test+ #171 [ 1257.829021] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007 [ 1257.829021] 0000000000000001 ffff880065f49da8 ffffffff8153dd2b ffff880065f49dd8 [ 1257.829021] ffffffff81092a00 ffff88006bd78680 ffff88007add7500 0000000000000003 [ 1257.829021] ffff88006bd78680 ffff880065f49e18 ffffffff810daebf ffffffff810dae5a [ 1257.829021] Call Trace: [ 1257.829021] [<ffffffff8153dd2b>] dump_stack+0x19/0x1b [ 1257.829021] [<ffffffff81092a00>] lockdep_rcu_suspicious+0x109/0x112 [ 1257.829021] [<ffffffff810daebf>] __update_max_tr+0xed/0x1ee [ 1257.829021] [<ffffffff810dae5a>] ? __update_max_tr+0x88/0x1ee [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810dbf85>] update_max_tr_single+0x11d/0x12d [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810e2b15>] stop_critical_timing+0x141/0x209 [ 1257.829021] [<ffffffff8109569a>] ? trace_hardirqs_on+0xd/0xf [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810e3057>] time_hardirqs_on+0x2a/0x2f [ 1257.829021] [<ffffffff811002b9>] ? user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff8109550c>] trace_hardirqs_on_caller+0x16/0x197 [ 1257.829021] [<ffffffff8109569a>] trace_hardirqs_on+0xd/0xf [ 1257.829021] [<ffffffff811002b9>] user_enter+0xfd/0x107 [ 1257.829021] [<ffffffff810029b4>] do_notify_resume+0x92/0x97 [ 1257.829021] [<ffffffff8154bdca>] int_signal+0x12/0x17 What happened was entering into the user code, the interrupts were enabled and a max interrupts off was recorded. The trace buffer was saved along with various information about the task: comm, pid, uid, priority, etc. The uid is recorded with task_uid(tsk). But this is a macro that uses rcu_read_lock() to retrieve the data, and this happened to happen where RCU is blind (user_enter). As only the preempt and irqs off tracers can have this happen, and they both only have the tsk == current, if tsk == current, use current_uid() instead of task_uid(), as current_uid() does not use RCU as only current can change its uid. This fixes the RCU suspicious splat. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-05-31 03:10:37 +02:00
/*
* If tsk == current, then use current_uid(), as that does not use
* RCU. The irq tracer can be called out of RCU scope.
*/
if (tsk == current)
max_data->uid = current_uid();
else
max_data->uid = task_uid(tsk);
max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
max_data->policy = tsk->policy;
max_data->rt_priority = tsk->rt_priority;
/* record this tasks comm */
tracing_record_cmdline(tsk);
}
/**
* update_max_tr - snapshot all trace buffers from global_trace to max_tr
* @tr: tracer
* @tsk: the task with the latency
* @cpu: The cpu that initiated the trace.
*
* Flip the buffers between the @tr and the max_tr and record information
* about which task was the cause of this latency.
*/
void
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
struct ring_buffer *buf;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (tr->stop_count)
return;
WARN_ON_ONCE(!irqs_disabled());
if (!tr->allocated_snapshot) {
/* Only the nop tracer should hit this when disabling */
WARN_ON_ONCE(tr->current_trace != &nop_trace);
return;
}
arch_spin_lock(&tr->max_lock);
buf = tr->trace_buffer.buffer;
tr->trace_buffer.buffer = tr->max_buffer.buffer;
tr->max_buffer.buffer = buf;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
__update_max_tr(tr, tsk, cpu);
arch_spin_unlock(&tr->max_lock);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
/**
* update_max_tr_single - only copy one trace over, and reset the rest
* @tr - tracer
* @tsk - task with the latency
* @cpu - the cpu of the buffer to copy.
*
* Flip the trace of a single CPU buffer between the @tr and the max_tr.
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
*/
void
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
int ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (tr->stop_count)
return;
WARN_ON_ONCE(!irqs_disabled());
if (!tr->allocated_snapshot) {
/* Only the nop tracer should hit this when disabling */
Tracing updates for Linux 3.10 Along with the usual minor fixes and clean ups there are a few major changes with this pull request. 1) Multiple buffers for the ftrace facility This feature has been requested by many people over the last few years. I even heard that Google was about to implement it themselves. I finally had time and cleaned up the code such that you can now create multiple instances of the ftrace buffer and have different events go to different buffers. This way, a low frequency event will not be lost in the noise of a high frequency event. Note, currently only events can go to different buffers, the tracers (ie. function, function_graph and the latency tracers) still can only be written to the main buffer. 2) The function tracer triggers have now been extended. The function tracer had two triggers. One to enable tracing when a function is hit, and one to disable tracing. Now you can record a stack trace on a single (or many) function(s), take a snapshot of the buffer (copy it to the snapshot buffer), and you can enable or disable an event to be traced when a function is hit. 3) A perf clock has been added. A "perf" clock can be chosen to be used when tracing. This will cause ftrace to use the same clock as perf uses, and hopefully this will make it easier to interleave the perf and ftrace data for analysis. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAABAgAGBQJRfnTPAAoJEOdOSU1xswtMqYYH/1WIdrwXmxHflErnYkCIr3sU QtYae2K5A1HcgiqOvRJrdWMOt016iMx5CaQQyBFM1vvMiPY0sTWRmwNxDfZzz9LN 10jRvWEzZSLtzl+a9mkFWLEpr5nR/QODOxkWFCnRWscp46sp04LSTxGDYsOnPQZB sam/AQ1h4xA+DqDBChm9BDEUEPorGleTlN54LBaCGgSFGvrbF+eAg2s4vHNAQAvQ 8d5xjSE9zC7J+FqbVxvJTbKI3+EqKL6hMsJKsKfi0SI+FuxBaFMSltXck5zKyTI4 HpNJzXCmw+v90Tju7oMkPHh6RTbESPCHoGU+wqE52fM6m7oScVeuI/kfc6USwU4= =W1n+ -----END PGP SIGNATURE----- Merge tag 'trace-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "Along with the usual minor fixes and clean ups there are a few major changes with this pull request. 1) Multiple buffers for the ftrace facility This feature has been requested by many people over the last few years. I even heard that Google was about to implement it themselves. I finally had time and cleaned up the code such that you can now create multiple instances of the ftrace buffer and have different events go to different buffers. This way, a low frequency event will not be lost in the noise of a high frequency event. Note, currently only events can go to different buffers, the tracers (ie function, function_graph and the latency tracers) still can only be written to the main buffer. 2) The function tracer triggers have now been extended. The function tracer had two triggers. One to enable tracing when a function is hit, and one to disable tracing. Now you can record a stack trace on a single (or many) function(s), take a snapshot of the buffer (copy it to the snapshot buffer), and you can enable or disable an event to be traced when a function is hit. 3) A perf clock has been added. A "perf" clock can be chosen to be used when tracing. This will cause ftrace to use the same clock as perf uses, and hopefully this will make it easier to interleave the perf and ftrace data for analysis." * tag 'trace-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (82 commits) tracepoints: Prevent null probe from being added tracing: Compare to 1 instead of zero for is_signed_type() tracing: Remove obsolete macro guard _TRACE_PROFILE_INIT ftrace: Get rid of ftrace_profile_bits tracing: Check return value of tracing_init_dentry() tracing: Get rid of unneeded key calculation in ftrace_hash_move() tracing: Reset ftrace_graph_filter_enabled if count is zero tracing: Fix off-by-one on allocating stat->pages kernel: tracing: Use strlcpy instead of strncpy tracing: Update debugfs README file tracing: Fix ftrace_dump() tracing: Rename trace_event_mutex to trace_event_sem tracing: Fix comment about prefix in arch_syscall_match_sym_name() tracing: Convert trace_destroy_fields() to static tracing: Move find_event_field() into trace_events.c tracing: Use TRACE_MAX_PRINT instead of constant tracing: Use pr_warn_once instead of open coded implementation ring-buffer: Add ring buffer startup selftest tracing: Bring Documentation/trace/ftrace.txt up to date tracing: Add "perf" trace_clock ... Conflicts: kernel/trace/ftrace.c kernel/trace/trace.c
2013-04-29 22:55:38 +02:00
WARN_ON_ONCE(tr->current_trace != &nop_trace);
tracing: Shrink max latency ringbuffer if unnecessary Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-01 07:34:35 +02:00
return;
}
tracing: Shrink max latency ringbuffer if unnecessary Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-01 07:34:35 +02:00
arch_spin_lock(&tr->max_lock);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
if (ret == -EBUSY) {
/*
* We failed to swap the buffer due to a commit taking
* place on this CPU. We fail to record, but we reset
* the max trace buffer (no one writes directly to it)
* and flag that it failed.
*/
trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
"Failed to swap buffers due to commit in progress\n");
}
WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
__update_max_tr(tr, tsk, cpu);
arch_spin_unlock(&tr->max_lock);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
#endif /* CONFIG_TRACER_MAX_TRACE */
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
tracing: Do not busy wait in buffer splice On a !PREEMPT kernel, attempting to use trace-cmd results in a soft lockup: # trace-cmd record -e raw_syscalls:* -F false NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [trace-cmd:61] ... Call Trace: [<ffffffff8105b580>] ? __wake_up_common+0x90/0x90 [<ffffffff81092e25>] wait_on_pipe+0x35/0x40 [<ffffffff810936e3>] tracing_buffers_splice_read+0x2e3/0x3c0 [<ffffffff81093300>] ? tracing_stats_read+0x2a0/0x2a0 [<ffffffff812d10ab>] ? _raw_spin_unlock+0x2b/0x40 [<ffffffff810dc87b>] ? do_read_fault+0x21b/0x290 [<ffffffff810de56a>] ? handle_mm_fault+0x2ba/0xbd0 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff810951e2>] ? trace_buffer_lock_reserve+0x22/0x60 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff8112415d>] do_splice_to+0x6d/0x90 [<ffffffff81126971>] SyS_splice+0x7c1/0x800 [<ffffffff812d1edd>] tracesys_phase2+0xd3/0xd8 The problem is this: tracing_buffers_splice_read() calls ring_buffer_wait() to wait for data in the ring buffers. The buffers are not empty so ring_buffer_wait() returns immediately. But tracing_buffers_splice_read() calls ring_buffer_read_page() with full=1, meaning it only wants to read a full page. When the full page is not available, tracing_buffers_splice_read() tries to wait again with ring_buffer_wait(), which again returns immediately, and so on. Fix this by adding a "full" argument to ring_buffer_wait() which will make ring_buffer_wait() wait until the writer has left the reader's page, i.e. until full-page reads will succeed. Link: http://lkml.kernel.org/r/1415645194-25379-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 3.16+ Fixes: b1169cc69ba9 ("tracing: Remove mock up poll wait function") Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-10 19:46:34 +01:00
static int wait_on_pipe(struct trace_iterator *iter, bool full)
{
/* Iterators are static, they should be filled or empty */
if (trace_buffer_iter(iter, iter->cpu_file))
return 0;
tracing: Do not busy wait in buffer splice On a !PREEMPT kernel, attempting to use trace-cmd results in a soft lockup: # trace-cmd record -e raw_syscalls:* -F false NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [trace-cmd:61] ... Call Trace: [<ffffffff8105b580>] ? __wake_up_common+0x90/0x90 [<ffffffff81092e25>] wait_on_pipe+0x35/0x40 [<ffffffff810936e3>] tracing_buffers_splice_read+0x2e3/0x3c0 [<ffffffff81093300>] ? tracing_stats_read+0x2a0/0x2a0 [<ffffffff812d10ab>] ? _raw_spin_unlock+0x2b/0x40 [<ffffffff810dc87b>] ? do_read_fault+0x21b/0x290 [<ffffffff810de56a>] ? handle_mm_fault+0x2ba/0xbd0 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff810951e2>] ? trace_buffer_lock_reserve+0x22/0x60 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff8112415d>] do_splice_to+0x6d/0x90 [<ffffffff81126971>] SyS_splice+0x7c1/0x800 [<ffffffff812d1edd>] tracesys_phase2+0xd3/0xd8 The problem is this: tracing_buffers_splice_read() calls ring_buffer_wait() to wait for data in the ring buffers. The buffers are not empty so ring_buffer_wait() returns immediately. But tracing_buffers_splice_read() calls ring_buffer_read_page() with full=1, meaning it only wants to read a full page. When the full page is not available, tracing_buffers_splice_read() tries to wait again with ring_buffer_wait(), which again returns immediately, and so on. Fix this by adding a "full" argument to ring_buffer_wait() which will make ring_buffer_wait() wait until the writer has left the reader's page, i.e. until full-page reads will succeed. Link: http://lkml.kernel.org/r/1415645194-25379-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 3.16+ Fixes: b1169cc69ba9 ("tracing: Remove mock up poll wait function") Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-10 19:46:34 +01:00
return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
full);
}
#ifdef CONFIG_FTRACE_STARTUP_TEST
static int run_tracer_selftest(struct tracer *type)
{
struct trace_array *tr = &global_trace;
struct tracer *saved_tracer = tr->current_trace;
int ret;
if (!type->selftest || tracing_selftest_disabled)
return 0;
/*
* Run a selftest on this tracer.
* Here we reset the trace buffer, and set the current
* tracer to be this tracer. The tracer can then run some
* internal tracing to verify that everything is in order.
* If we fail, we do not register this tracer.
*/
tracing_reset_online_cpus(&tr->trace_buffer);
tr->current_trace = type;
#ifdef CONFIG_TRACER_MAX_TRACE
if (type->use_max_tr) {
/* If we expanded the buffers, make sure the max is expanded too */
if (ring_buffer_expanded)
ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
RING_BUFFER_ALL_CPUS);
tr->allocated_snapshot = true;
}
#endif
/* the test is responsible for initializing and enabling */
pr_info("Testing tracer %s: ", type->name);
ret = type->selftest(type, tr);
/* the test is responsible for resetting too */
tr->current_trace = saved_tracer;
if (ret) {
printk(KERN_CONT "FAILED!\n");
/* Add the warning after printing 'FAILED' */
WARN_ON(1);
return -1;
}
/* Only reset on passing, to avoid touching corrupted buffers */
tracing_reset_online_cpus(&tr->trace_buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
if (type->use_max_tr) {
tr->allocated_snapshot = false;
/* Shrink the max buffer again */
if (ring_buffer_expanded)
ring_buffer_resize(tr->max_buffer.buffer, 1,
RING_BUFFER_ALL_CPUS);
}
#endif
printk(KERN_CONT "PASSED\n");
return 0;
}
#else
static inline int run_tracer_selftest(struct tracer *type)
{
return 0;
}
#endif /* CONFIG_FTRACE_STARTUP_TEST */
static void add_tracer_options(struct trace_array *tr, struct tracer *t);
static void __init apply_trace_boot_options(void);
/**
* register_tracer - register a tracer with the ftrace system.
* @type - the plugin for the tracer
*
* Register a new plugin tracer.
*/
int __init register_tracer(struct tracer *type)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct tracer *t;
int ret = 0;
if (!type->name) {
pr_info("Tracer must have a name\n");
return -1;
}
if (strlen(type->name) >= MAX_TRACER_SIZE) {
pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
return -1;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_lock(&trace_types_lock);
ftrace: fix selftest locking Impact: fix self-test boot crash Self-test failure forgot to re-lock the BKL - crashing the next initcall: Testing tracer irqsoff: .. no entries found ..FAILED! initcall init_irqsoff_tracer+0x0/0x11 returned 0 after 3906 usecs calling init_mmio_trace+0x0/0xf @ 1 ------------[ cut here ]------------ Kernel BUG at c0c0a915 [verbose debug info unavailable] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC last sysfs file: Pid: 1, comm: swapper Not tainted (2.6.28-rc5-tip #53704) EIP: 0060:[<c0c0a915>] EFLAGS: 00010286 CPU: 1 EIP is at unlock_kernel+0x10/0x2b EAX: ffffffff EBX: 00000000 ECX: 00000000 EDX: f7030000 ESI: c12da19c EDI: 00000000 EBP: f7039f54 ESP: f7039f54 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 Process swapper (pid: 1, ti=f7038000 task=f7030000 task.ti=f7038000) Stack: f7039f6c c0164d30 c013fed8 a7d8d7b4 00000000 00000000 f7039f74 c12fb78a f7039fd0 c0101132 c12fb77d 00000000 6f727200 6f632072 2d206564 c1002031 0000000f f7039fa2 f7039fb0 3531b171 00000000 00000000 0000002f c12ca480 Call Trace: [<c0164d30>] ? register_tracer+0x66/0x13f [<c013fed8>] ? ktime_get+0x19/0x1b [<c12fb78a>] ? init_mmio_trace+0xd/0xf [<c0101132>] ? do_one_initcall+0x4a/0x111 [<c12fb77d>] ? init_mmio_trace+0x0/0xf [<c015c7e6>] ? init_irq_proc+0x46/0x59 [<c12e851d>] ? kernel_init+0x104/0x152 [<c12e8419>] ? kernel_init+0x0/0x152 [<c01038b7>] ? kernel_thread_helper+0x7/0x10 Code: 58 14 43 75 0a b8 00 9b 2d c1 e8 51 43 7a ff 64 a1 00 a0 37 c1 89 58 14 5b 5d c3 55 64 8b 15 00 a0 37 c1 83 7a 14 00 89 e5 79 04 <0f> 0b eb fe 8b 42 14 48 85 c0 89 42 14 79 0a b8 00 9b 2d c1 e8 EIP: [<c0c0a915>] unlock_kernel+0x10/0x2b SS:ESP 0068:f7039f54 ---[ end trace a7919e7f17c0a725 ]--- Kernel panic - not syncing: Attempted to kill init! So clean up the flow a bit. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-19 10:00:15 +01:00
tracing_selftest_running = true;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
for (t = trace_types; t; t = t->next) {
if (strcmp(type->name, t->name) == 0) {
/* already found */
pr_info("Tracer %s already registered\n",
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
type->name);
ret = -1;
goto out;
}
}
if (!type->set_flag)
type->set_flag = &dummy_set_flag;
tracing: Make tracer_flags use the right set_flag callback When I was updating the ftrace_stress test of ltp. I encountered a strange phenomemon, excute following steps: echo nop > /sys/kernel/debug/tracing/current_tracer echo 0 > /sys/kernel/debug/tracing/options/funcgraph-cpu bash: echo: write error: Invalid argument check dmesg: [ 1024.903855] nop_test_refuse flag set to 0: we refuse.Now cat trace_options to see the result The reason is that the trace option test will randomly setup trace option under tracing/options no matter what the current_tracer is. but the set_tracer_option is always using the set_flag callback from the current_tracer. This patch adds a pointer to tracer_flags and make it point to the tracer it belongs to. When the option is setup, the set_flag of the right tracer will be used no matter what the the current_tracer is. And the old dummy_tracer_flags is used for all the tracers which doesn't have a tracer_flags, having issue to use it to save the pointer of a tracer. So remove it and use dynamic dummy tracer_flags for tracers needing a dummy tracer_flags, as a result, there are no tracers sharing tracer_flags, so remove the check code. And save the current tracer to trace_option_dentry seems not good as it may waste mem space when mount the debug/trace fs more than one time. Link: http://lkml.kernel.org/r/1457444222-8654-1-git-send-email-chuhu@redhat.com Signed-off-by: Chunyu Hu <chuhu@redhat.com> [ Fixed up function tracer options to work with the change ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-08 14:37:01 +01:00
if (!type->flags) {
/*allocate a dummy tracer_flags*/
type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
if (!type->flags) {
ret = -ENOMEM;
goto out;
}
tracing: Make tracer_flags use the right set_flag callback When I was updating the ftrace_stress test of ltp. I encountered a strange phenomemon, excute following steps: echo nop > /sys/kernel/debug/tracing/current_tracer echo 0 > /sys/kernel/debug/tracing/options/funcgraph-cpu bash: echo: write error: Invalid argument check dmesg: [ 1024.903855] nop_test_refuse flag set to 0: we refuse.Now cat trace_options to see the result The reason is that the trace option test will randomly setup trace option under tracing/options no matter what the current_tracer is. but the set_tracer_option is always using the set_flag callback from the current_tracer. This patch adds a pointer to tracer_flags and make it point to the tracer it belongs to. When the option is setup, the set_flag of the right tracer will be used no matter what the the current_tracer is. And the old dummy_tracer_flags is used for all the tracers which doesn't have a tracer_flags, having issue to use it to save the pointer of a tracer. So remove it and use dynamic dummy tracer_flags for tracers needing a dummy tracer_flags, as a result, there are no tracers sharing tracer_flags, so remove the check code. And save the current tracer to trace_option_dentry seems not good as it may waste mem space when mount the debug/trace fs more than one time. Link: http://lkml.kernel.org/r/1457444222-8654-1-git-send-email-chuhu@redhat.com Signed-off-by: Chunyu Hu <chuhu@redhat.com> [ Fixed up function tracer options to work with the change ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-08 14:37:01 +01:00
type->flags->val = 0;
type->flags->opts = dummy_tracer_opt;
} else
if (!type->flags->opts)
type->flags->opts = dummy_tracer_opt;
tracing: Make tracer_flags use the right set_flag callback When I was updating the ftrace_stress test of ltp. I encountered a strange phenomemon, excute following steps: echo nop > /sys/kernel/debug/tracing/current_tracer echo 0 > /sys/kernel/debug/tracing/options/funcgraph-cpu bash: echo: write error: Invalid argument check dmesg: [ 1024.903855] nop_test_refuse flag set to 0: we refuse.Now cat trace_options to see the result The reason is that the trace option test will randomly setup trace option under tracing/options no matter what the current_tracer is. but the set_tracer_option is always using the set_flag callback from the current_tracer. This patch adds a pointer to tracer_flags and make it point to the tracer it belongs to. When the option is setup, the set_flag of the right tracer will be used no matter what the the current_tracer is. And the old dummy_tracer_flags is used for all the tracers which doesn't have a tracer_flags, having issue to use it to save the pointer of a tracer. So remove it and use dynamic dummy tracer_flags for tracers needing a dummy tracer_flags, as a result, there are no tracers sharing tracer_flags, so remove the check code. And save the current tracer to trace_option_dentry seems not good as it may waste mem space when mount the debug/trace fs more than one time. Link: http://lkml.kernel.org/r/1457444222-8654-1-git-send-email-chuhu@redhat.com Signed-off-by: Chunyu Hu <chuhu@redhat.com> [ Fixed up function tracer options to work with the change ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-08 14:37:01 +01:00
/* store the tracer for __set_tracer_option */
type->flags->trace = type;
ret = run_tracer_selftest(type);
if (ret < 0)
goto out;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
type->next = trace_types;
trace_types = type;
add_tracer_options(&global_trace, type);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
out:
tracing_selftest_running = false;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_unlock(&trace_types_lock);
if (ret || !default_bootup_tracer)
goto out_unlock;
if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
goto out_unlock;
printk(KERN_INFO "Starting tracer '%s'\n", type->name);
/* Do we want this tracer to start on bootup? */
tracing_set_tracer(&global_trace, type->name);
default_bootup_tracer = NULL;
apply_trace_boot_options();
/* disable other selftests, since this will break it. */
tracing_selftest_disabled = true;
#ifdef CONFIG_FTRACE_STARTUP_TEST
printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
type->name);
#endif
out_unlock:
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return ret;
}
void tracing_reset(struct trace_buffer *buf, int cpu)
{
struct ring_buffer *buffer = buf->buffer;
if (!buffer)
return;
ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */
synchronize_sched();
ring_buffer_reset_cpu(buffer, cpu);
ring_buffer_record_enable(buffer);
}
void tracing_reset_online_cpus(struct trace_buffer *buf)
{
struct ring_buffer *buffer = buf->buffer;
int cpu;
if (!buffer)
return;
ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */
synchronize_sched();
buf->time_start = buffer_ftrace_now(buf, buf->cpu);
for_each_online_cpu(cpu)
ring_buffer_reset_cpu(buffer, cpu);
ring_buffer_record_enable(buffer);
}
/* Must have trace_types_lock held */
void tracing_reset_all_online_cpus(void)
{
struct trace_array *tr;
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
tracing_reset_online_cpus(&tr->trace_buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
tracing_reset_online_cpus(&tr->max_buffer);
#endif
}
}
#define SAVED_CMDLINES_DEFAULT 128
#define NO_CMDLINE_MAP UINT_MAX
static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
struct saved_cmdlines_buffer {
unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
unsigned *map_cmdline_to_pid;
unsigned cmdline_num;
int cmdline_idx;
char *saved_cmdlines;
};
static struct saved_cmdlines_buffer *savedcmd;
/* temporary disable recording */
static atomic_t trace_record_cmdline_disabled __read_mostly;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static inline char *get_saved_cmdlines(int idx)
{
return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
}
static inline void set_cmdline(int idx, const char *cmdline)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
}
static int allocate_cmdlines_buffer(unsigned int val,
struct saved_cmdlines_buffer *s)
{
s->map_cmdline_to_pid = kmalloc(val * sizeof(*s->map_cmdline_to_pid),
GFP_KERNEL);
if (!s->map_cmdline_to_pid)
return -ENOMEM;
s->saved_cmdlines = kmalloc(val * TASK_COMM_LEN, GFP_KERNEL);
if (!s->saved_cmdlines) {
kfree(s->map_cmdline_to_pid);
return -ENOMEM;
}
s->cmdline_idx = 0;
s->cmdline_num = val;
memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
sizeof(s->map_pid_to_cmdline));
memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
val * sizeof(*s->map_cmdline_to_pid));
return 0;
}
static int trace_create_savedcmd(void)
{
int ret;
savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
if (!savedcmd)
return -ENOMEM;
ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
if (ret < 0) {
kfree(savedcmd);
savedcmd = NULL;
return -ENOMEM;
}
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
int is_tracing_stopped(void)
{
return global_trace.stop_count;
}
/**
* tracing_start - quick start of the tracer
*
* If tracing is enabled but was stopped by tracing_stop,
* this will start the tracer back up.
*/
void tracing_start(void)
{
struct ring_buffer *buffer;
unsigned long flags;
if (tracing_disabled)
return;
raw_spin_lock_irqsave(&global_trace.start_lock, flags);
if (--global_trace.stop_count) {
if (global_trace.stop_count < 0) {
/* Someone screwed up their debugging */
WARN_ON_ONCE(1);
global_trace.stop_count = 0;
}
goto out;
}
/* Prevent the buffers from switching */
arch_spin_lock(&global_trace.max_lock);
buffer = global_trace.trace_buffer.buffer;
if (buffer)
ring_buffer_record_enable(buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
buffer = global_trace.max_buffer.buffer;
if (buffer)
ring_buffer_record_enable(buffer);
#endif
arch_spin_unlock(&global_trace.max_lock);
out:
raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
}
static void tracing_start_tr(struct trace_array *tr)
{
struct ring_buffer *buffer;
unsigned long flags;
if (tracing_disabled)
return;
/* If global, we need to also start the max tracer */
if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
return tracing_start();
raw_spin_lock_irqsave(&tr->start_lock, flags);
if (--tr->stop_count) {
if (tr->stop_count < 0) {
/* Someone screwed up their debugging */
WARN_ON_ONCE(1);
tr->stop_count = 0;
}
goto out;
}
buffer = tr->trace_buffer.buffer;
if (buffer)
ring_buffer_record_enable(buffer);
out:
raw_spin_unlock_irqrestore(&tr->start_lock, flags);
}
/**
* tracing_stop - quick stop of the tracer
*
* Light weight way to stop tracing. Use in conjunction with
* tracing_start.
*/
void tracing_stop(void)
{
struct ring_buffer *buffer;
unsigned long flags;
raw_spin_lock_irqsave(&global_trace.start_lock, flags);
if (global_trace.stop_count++)
goto out;
/* Prevent the buffers from switching */
arch_spin_lock(&global_trace.max_lock);
buffer = global_trace.trace_buffer.buffer;
if (buffer)
ring_buffer_record_disable(buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
buffer = global_trace.max_buffer.buffer;
if (buffer)
ring_buffer_record_disable(buffer);
#endif
arch_spin_unlock(&global_trace.max_lock);
out:
raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
}
static void tracing_stop_tr(struct trace_array *tr)
{
struct ring_buffer *buffer;
unsigned long flags;
/* If global, we need to also stop the max tracer */
if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
return tracing_stop();
raw_spin_lock_irqsave(&tr->start_lock, flags);
if (tr->stop_count++)
goto out;
buffer = tr->trace_buffer.buffer;
if (buffer)
ring_buffer_record_disable(buffer);
out:
raw_spin_unlock_irqrestore(&tr->start_lock, flags);
}
void trace_stop_cmdline_recording(void);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static int trace_save_cmdline(struct task_struct *tsk)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
unsigned pid, idx;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/*
* It's not the end of the world if we don't get
* the lock, but we also don't want to spin
* nor do we want to disable interrupts,
* so if we miss here, then better luck next time.
*/
if (!arch_spin_trylock(&trace_cmdline_lock))
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
idx = savedcmd->map_pid_to_cmdline[tsk->pid];
if (idx == NO_CMDLINE_MAP) {
idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/*
* Check whether the cmdline buffer at idx has a pid
* mapped. We are going to overwrite that entry so we
* need to clear the map_pid_to_cmdline. Otherwise we
* would read the new comm for the old pid.
*/
pid = savedcmd->map_cmdline_to_pid[idx];
if (pid != NO_CMDLINE_MAP)
savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
savedcmd->map_pid_to_cmdline[tsk->pid] = idx;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
savedcmd->cmdline_idx = idx;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
set_cmdline(idx, tsk->comm);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
arch_spin_unlock(&trace_cmdline_lock);
return 1;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static void __trace_find_cmdline(int pid, char comm[])
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
unsigned map;
if (!pid) {
strcpy(comm, "<idle>");
return;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (WARN_ON_ONCE(pid < 0)) {
strcpy(comm, "<XXX>");
return;
}
if (pid > PID_MAX_DEFAULT) {
strcpy(comm, "<...>");
return;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
map = savedcmd->map_pid_to_cmdline[pid];
if (map != NO_CMDLINE_MAP)
strcpy(comm, get_saved_cmdlines(map));
else
strcpy(comm, "<...>");
}
void trace_find_cmdline(int pid, char comm[])
{
preempt_disable();
arch_spin_lock(&trace_cmdline_lock);
__trace_find_cmdline(pid, comm);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
arch_spin_unlock(&trace_cmdline_lock);
trace: disable preemption before taking raw spinlocks s390 code uses smp_processor_id() in __raw_spin_lock() code which reveals that a (raw) spinlock is taken without preemption disabled. This can potentially deadlock. To fix this explicitly disable and enable preemption. BUG: using smp_processor_id() in preemptible [00000000] code: cat/2278 caller is trace_find_cmdline+0x40/0xfc CPU: 0 Not tainted 2.6.30-rc7-dirty #39 Process cat (pid: 2278, task: 000000003faedb68, ksp: 000000003b33b988) 000000003b33b988 000000003b33bae0 0000000000000002 0000000000000000 000000003b33bb80 000000003b33baf8 000000003b33baf8 00000000000175d6 0000000000000001 000000003b33b988 000000003f9b0000 000000000000000b 000000000000000c 000000003b33bb40 000000003b33bae0 0000000000000000 0000000000000000 00000000000175d6 000000003b33bae0 000000003b33bb28 Call Trace: ([<00000000000174b2>] show_trace+0x112/0x170) [<0000000000017582>] show_stack+0x72/0x100 [<0000000000441538>] dump_stack+0xc8/0xd8 [<000000000025c350>] debug_smp_processor_id+0x114/0x130 [<00000000000bf0e4>] trace_find_cmdline+0x40/0xfc [<00000000000c35d4>] trace_print_context+0x58/0xac [<00000000000bb676>] print_trace_line+0x416/0x470 [<00000000000bc8fe>] s_show+0x4e/0x428 [<000000000013834e>] seq_read+0x36a/0x5d4 [<0000000000112a78>] vfs_read+0xc8/0x174 [<0000000000112c58>] SyS_read+0x74/0xc4 [<000000000002c7ae>] sysc_noemu+0x10/0x16 [<000002000012436c>] 0x2000012436c 1 lock held by cat/2278: #0: (&p->lock){+.+.+.}, at: [<0000000000138056>] seq_read+0x72/0x5d4 [ Impact: fix preempt-unsafe raw spinlock ] Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 17:28:02 +02:00
preempt_enable();
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
void tracing_record_cmdline(struct task_struct *tsk)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return;
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
if (!__this_cpu_read(trace_cmdline_save))
return;
if (trace_save_cmdline(tsk))
__this_cpu_write(trace_cmdline_save, false);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
void
tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
int pc)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct task_struct *tsk = current;
entry->preempt_count = pc & 0xff;
entry->pid = (tsk) ? tsk->pid : 0;
entry->flags =
#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
#else
TRACE_FLAG_IRQS_NOSUPPORT |
#endif
((pc & NMI_MASK ) ? TRACE_FLAG_NMI : 0) |
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
perf_counter: Fix/complete ftrace event records sampling This patch implements the kernel side support for ftrace event record sampling. A new counter sampling attribute is added: PERF_SAMPLE_TP_RECORD which requests ftrace events record sampling. In this case if a PERF_TYPE_TRACEPOINT counter is active and a tracepoint fires, we emit the tracepoint binary record to the perfcounter event buffer, as a sample. Result, after setting PERF_SAMPLE_TP_RECORD attribute from perf record: perf record -f -F 1 -a -e workqueue:workqueue_execution perf report -D 0x21e18 [0x48]: event: 9 . . ... raw event: size 72 bytes . 0000: 09 00 00 00 01 00 48 00 d0 c7 00 81 ff ff ff ff ......H........ . 0010: 0a 00 00 00 0a 00 00 00 21 00 00 00 00 00 00 00 ........!...... . 0020: 2b 00 01 02 0a 00 00 00 0a 00 00 00 65 76 65 6e +...........eve . 0030: 74 73 2f 31 00 00 00 00 00 00 00 00 0a 00 00 00 ts/1........... . 0040: e0 b1 31 81 ff ff ff ff ....... . 0x21e18 [0x48]: PERF_EVENT_SAMPLE (IP, 1): 10: 0xffffffff8100c7d0 period: 33 The raw ftrace binary record starts at offset 0020. Translation: struct trace_entry { type = 0x2b = 43; flags = 1; preempt_count = 2; pid = 0xa = 10; tgid = 0xa = 10; } thread_comm = "events/1" thread_pid = 0xa = 10; func = 0xffffffff8131b1e0 = flush_to_ldisc() What will come next? - Userspace support ('perf trace'), 'flight data recorder' mode for perf trace, etc. - The unconditional copy from the profiling callback brings some costs however if someone wants no such sampling to occur, and needs to be fixed in the future. For that we need to have an instant access to the perf counter attribute. This is a matter of a flag to add in the struct ftrace_event. - Take care of the events recursivity! Don't ever try to record a lock event for example, it seems some locking is used in the profiling fast path and lead to a tracing recursivity. That will be fixed using raw spinlock or recursivity protection. - [...] - Profit! :-) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-07 01:25:54 +02:00
EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
static __always_inline void
trace_event_setup(struct ring_buffer_event *event,
int type, unsigned long flags, int pc)
{
struct trace_entry *ent = ring_buffer_event_data(event);
tracing_generic_entry_update(ent, flags, pc);
ent->type = type;
}
struct ring_buffer_event *
trace_buffer_lock_reserve(struct ring_buffer *buffer,
int type,
unsigned long len,
unsigned long flags, int pc)
{
struct ring_buffer_event *event;
event = ring_buffer_lock_reserve(buffer, len);
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
if (event != NULL)
trace_event_setup(event, type, flags, pc);
return event;
}
DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
DEFINE_PER_CPU(int, trace_buffered_event_cnt);
static int trace_buffered_event_ref;
/**
* trace_buffered_event_enable - enable buffering events
*
* When events are being filtered, it is quicker to use a temporary
* buffer to write the event data into if there's a likely chance
* that it will not be committed. The discard of the ring buffer
* is not as fast as committing, and is much slower than copying
* a commit.
*
* When an event is to be filtered, allocate per cpu buffers to
* write the event data into, and if the event is filtered and discarded
* it is simply dropped, otherwise, the entire data is to be committed
* in one shot.
*/
void trace_buffered_event_enable(void)
{
struct ring_buffer_event *event;
struct page *page;
int cpu;
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
if (trace_buffered_event_ref++)
return;
for_each_tracing_cpu(cpu) {
page = alloc_pages_node(cpu_to_node(cpu),
GFP_KERNEL | __GFP_NORETRY, 0);
if (!page)
goto failed;
event = page_address(page);
memset(event, 0, sizeof(*event));
per_cpu(trace_buffered_event, cpu) = event;
preempt_disable();
if (cpu == smp_processor_id() &&
this_cpu_read(trace_buffered_event) !=
per_cpu(trace_buffered_event, cpu))
WARN_ON_ONCE(1);
preempt_enable();
}
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
return;
failed:
trace_buffered_event_disable();
}
static void enable_trace_buffered_event(void *data)
{
/* Probably not needed, but do it anyway */
smp_rmb();
this_cpu_dec(trace_buffered_event_cnt);
}
static void disable_trace_buffered_event(void *data)
{
this_cpu_inc(trace_buffered_event_cnt);
}
/**
* trace_buffered_event_disable - disable buffering events
*
* When a filter is removed, it is faster to not use the buffered
* events, and to commit directly into the ring buffer. Free up
* the temp buffers when there are no more users. This requires
* special synchronization with current events.
*/
void trace_buffered_event_disable(void)
{
int cpu;
WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
if (WARN_ON_ONCE(!trace_buffered_event_ref))
return;
if (--trace_buffered_event_ref)
return;
preempt_disable();
/* For each CPU, set the buffer as used. */
smp_call_function_many(tracing_buffer_mask,
disable_trace_buffered_event, NULL, 1);
preempt_enable();
/* Wait for all current users to finish */
synchronize_sched();
for_each_tracing_cpu(cpu) {
free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
per_cpu(trace_buffered_event, cpu) = NULL;
}
/*
* Make sure trace_buffered_event is NULL before clearing
* trace_buffered_event_cnt.
*/
smp_wmb();
preempt_disable();
/* Do the work on each cpu */
smp_call_function_many(tracing_buffer_mask,
enable_trace_buffered_event, NULL, 1);
preempt_enable();
}
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
void
__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
{
__this_cpu_write(trace_cmdline_save, true);
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
/* If this is the temp buffer, we need to commit fully */
if (this_cpu_read(trace_buffered_event) == event) {
/* Length is in event->array[0] */
ring_buffer_write(buffer, event->array[0], &event->array[1]);
/* Release the temp buffer */
this_cpu_dec(trace_buffered_event_cnt);
} else
ring_buffer_unlock_commit(buffer, event);
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
}
static struct ring_buffer *temp_buffer;
struct ring_buffer_event *
trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
struct trace_event_file *trace_file,
int type, unsigned long len,
unsigned long flags, int pc)
{
struct ring_buffer_event *entry;
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
int val;
*current_rb = trace_file->tr->trace_buffer.buffer;
tracing: Use temp buffer when filtering events Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 23:15:43 +02:00
if ((trace_file->flags &
(EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
(entry = this_cpu_read(trace_buffered_event))) {
/* Try to use the per cpu buffer first */
val = this_cpu_inc_return(trace_buffered_event_cnt);
if (val == 1) {
trace_event_setup(entry, type, flags, pc);
entry->array[0] = len;
return entry;
}
this_cpu_dec(trace_buffered_event_cnt);
}
entry = trace_buffer_lock_reserve(*current_rb,
type, len, flags, pc);
/*
* If tracing is off, but we have triggers enabled
* we still need to look at the event data. Use the temp_buffer
* to store the trace event for the tigger to use. It's recusive
* safe and will not be recorded anywhere.
*/
if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
*current_rb = temp_buffer;
entry = trace_buffer_lock_reserve(*current_rb,
type, len, flags, pc);
}
return entry;
}
EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
void trace_buffer_unlock_commit_regs(struct trace_array *tr,
struct ring_buffer *buffer,
struct ring_buffer_event *event,
unsigned long flags, int pc,
struct pt_regs *regs)
tracing/kprobes: Fix kprobe-tracer to support stack trace Fix to support kernel stack trace correctly on kprobe-tracer. Since the execution path of kprobe-based dynamic events is different from other tracepoint-based events, normal ftrace_trace_stack() doesn't work correctly. To fix that, this introduces ftrace_trace_stack_regs() which traces stack via pt_regs instead of current stack register. e.g. # echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events # echo 1 > /sys/kernel/debug/tracing/options/stacktrace # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable # head -n 20 /sys/kernel/debug/tracing/trace bash-2968 [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca) bash-2968 [000] 10297.050247: <stack trace> => schedule_timeout => n_tty_read => tty_read => vfs_read => sys_read => system_call_fastpath kworker/0:1-2940 [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca) kworker/0:1-2940 [000] 10297.050266: <stack trace> => worker_thread => kthread => kernel_thread_helper sshd-1132 [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca) sshd-1132 [000] 10297.050365: <stack trace> => sysret_careful Note: Even with this fix, the first entry will be skipped if the probe is put on the function entry area before the frame pointer is set up (usually, that is 4 bytes (push %bp; mov %sp %bp) on x86), because stack unwinder depends on the frame pointer. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Namhyung Kim <namhyung@gmail.com> Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-08 09:09:34 +02:00
{
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
__buffer_unlock_commit(buffer, event);
tracing/kprobes: Fix kprobe-tracer to support stack trace Fix to support kernel stack trace correctly on kprobe-tracer. Since the execution path of kprobe-based dynamic events is different from other tracepoint-based events, normal ftrace_trace_stack() doesn't work correctly. To fix that, this introduces ftrace_trace_stack_regs() which traces stack via pt_regs instead of current stack register. e.g. # echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events # echo 1 > /sys/kernel/debug/tracing/options/stacktrace # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable # head -n 20 /sys/kernel/debug/tracing/trace bash-2968 [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca) bash-2968 [000] 10297.050247: <stack trace> => schedule_timeout => n_tty_read => tty_read => vfs_read => sys_read => system_call_fastpath kworker/0:1-2940 [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca) kworker/0:1-2940 [000] 10297.050266: <stack trace> => worker_thread => kthread => kernel_thread_helper sshd-1132 [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca) sshd-1132 [000] 10297.050365: <stack trace> => sysret_careful Note: Even with this fix, the first entry will be skipped if the probe is put on the function entry area before the frame pointer is set up (usually, that is 4 bytes (push %bp; mov %sp %bp) on x86), because stack unwinder depends on the frame pointer. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Namhyung Kim <namhyung@gmail.com> Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-08 09:09:34 +02:00
tracing: Skip more functions when doing stack tracing of events # echo 1 > options/stacktrace # echo 1 > events/sched/sched_switch/enable # cat trace <idle>-0 [002] d..2 1982.525169: <stack trace> => save_stack_trace => __ftrace_trace_stack => trace_buffer_unlock_commit_regs => event_trigger_unlock_commit => trace_event_buffer_commit => trace_event_raw_event_sched_switch => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => start_secondary The above shows that we are seeing 6 functions before ever making it to the caller of the sched_switch event. # echo stacktrace > events/sched/sched_switch/trigger # cat trace <idle>-0 [002] d..3 2146.335208: <stack trace> => trace_event_buffer_commit => trace_event_raw_event_sched_switch => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => start_secondary The stacktrace trigger isn't as bad, because it adds its own skip to the stacktracing, but still has two events extra. One issue is that if the stacktrace passes its own "regs" then there should be no addition to the skip, as the regs will not include the functions being called. This was an issue that was fixed by commit 7717c6be6999 ("tracing: Fix stacktrace skip depth in trace_buffer_unlock_commit_regs()" as adding the skip number for kprobes made the probes not have any stack at all. But since this is only an issue when regs is being used, a skip should be added if regs is NULL. Now we have: # echo 1 > options/stacktrace # echo 1 > events/sched/sched_switch/enable # cat trace <idle>-0 [000] d..2 1297.676333: <stack trace> => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => rest_init => start_kernel => x86_64_start_reservations => x86_64_start_kernel # echo stacktrace > events/sched/sched_switch/trigger # cat trace <idle>-0 [002] d..3 1370.759745: <stack trace> => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => start_secondary And kprobes are not touched. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-06-23 20:03:47 +02:00
/*
* If regs is not set, then skip the following callers:
* trace_buffer_unlock_commit_regs
* event_trigger_unlock_commit
* trace_event_buffer_commit
* trace_event_raw_event_sched_switch
* Note, we can still get here via blktrace, wakeup tracer
* and mmiotrace, but that's ok if they lose a function or
* two. They are that meaningful.
*/
ftrace_trace_stack(tr, buffer, flags, regs ? 0 : 4, pc, regs);
tracing/kprobes: Fix kprobe-tracer to support stack trace Fix to support kernel stack trace correctly on kprobe-tracer. Since the execution path of kprobe-based dynamic events is different from other tracepoint-based events, normal ftrace_trace_stack() doesn't work correctly. To fix that, this introduces ftrace_trace_stack_regs() which traces stack via pt_regs instead of current stack register. e.g. # echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events # echo 1 > /sys/kernel/debug/tracing/options/stacktrace # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable # head -n 20 /sys/kernel/debug/tracing/trace bash-2968 [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca) bash-2968 [000] 10297.050247: <stack trace> => schedule_timeout => n_tty_read => tty_read => vfs_read => sys_read => system_call_fastpath kworker/0:1-2940 [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca) kworker/0:1-2940 [000] 10297.050266: <stack trace> => worker_thread => kthread => kernel_thread_helper sshd-1132 [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca) sshd-1132 [000] 10297.050365: <stack trace> => sysret_careful Note: Even with this fix, the first entry will be skipped if the probe is put on the function entry area before the frame pointer is set up (usually, that is 4 bytes (push %bp; mov %sp %bp) on x86), because stack unwinder depends on the frame pointer. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Namhyung Kim <namhyung@gmail.com> Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-08 09:09:34 +02:00
ftrace_trace_userstack(buffer, flags, pc);
}
void
trace_function(struct trace_array *tr,
unsigned long ip, unsigned long parent_ip, unsigned long flags,
int pc)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct trace_event_call *call = &event_function;
struct ring_buffer *buffer = tr->trace_buffer.buffer;
struct ring_buffer_event *event;
struct ftrace_entry *entry;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
flags, pc);
if (!event)
return;
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->parent_ip = parent_ip;
tracing/filters: add run-time field descriptions to TRACE_EVENT_FORMAT events This patch adds run-time field descriptions to all the event formats exported using TRACE_EVENT_FORMAT. It also hooks up all the tracers that use them (i.e. the tracers in the 'ftrace subsystem') so they can also have their output filtered by the event-filtering mechanism. When I was testing this, there were a couple of things that fooled me into thinking the filters weren't working, when actually they were - I'll mention them here so others don't make the same mistakes (and file bug reports. ;-) One is that some of the tracers trace multiple events e.g. the sched_switch tracer uses the context_switch and wakeup events, and if you don't set filters on all of the traced events, the unfiltered output from the events without filters on them can make it look like the filtering as a whole isn't working properly, when actually it is doing what it was asked to do - it just wasn't asked to do the right thing. The other is that for the really high-volume tracers e.g. the function tracer, the volume of filtered events can be so high that it pushes the unfiltered events out of the ring buffer before they can be read so e.g. cat'ing the trace file repeatedly shows either no output, or once in awhile some output but that isn't there the next time you read the trace, which isn't what you normally expect when reading the trace file. If you read from the trace_pipe file though, you can catch them before they disappear. Changes from v1: As suggested by Frederic Weisbecker: - get rid of externs in functions - added unlikely() to filter_check_discard() Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-31 07:48:49 +02:00
tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:34:17 +02:00
if (!call_filter_check_discard(call, entry, buffer, event))
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
__buffer_unlock_commit(buffer, event);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
#ifdef CONFIG_STACKTRACE
#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
struct ftrace_stack {
unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
};
static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
static DEFINE_PER_CPU(int, ftrace_stack_reserve);
static void __ftrace_trace_stack(struct ring_buffer *buffer,
unsigned long flags,
tracing/kprobes: Fix kprobe-tracer to support stack trace Fix to support kernel stack trace correctly on kprobe-tracer. Since the execution path of kprobe-based dynamic events is different from other tracepoint-based events, normal ftrace_trace_stack() doesn't work correctly. To fix that, this introduces ftrace_trace_stack_regs() which traces stack via pt_regs instead of current stack register. e.g. # echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events # echo 1 > /sys/kernel/debug/tracing/options/stacktrace # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable # head -n 20 /sys/kernel/debug/tracing/trace bash-2968 [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca) bash-2968 [000] 10297.050247: <stack trace> => schedule_timeout => n_tty_read => tty_read => vfs_read => sys_read => system_call_fastpath kworker/0:1-2940 [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca) kworker/0:1-2940 [000] 10297.050266: <stack trace> => worker_thread => kthread => kernel_thread_helper sshd-1132 [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca) sshd-1132 [000] 10297.050365: <stack trace> => sysret_careful Note: Even with this fix, the first entry will be skipped if the probe is put on the function entry area before the frame pointer is set up (usually, that is 4 bytes (push %bp; mov %sp %bp) on x86), because stack unwinder depends on the frame pointer. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Namhyung Kim <namhyung@gmail.com> Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-08 09:09:34 +02:00
int skip, int pc, struct pt_regs *regs)
{
struct trace_event_call *call = &event_kernel_stack;
struct ring_buffer_event *event;
struct stack_entry *entry;
struct stack_trace trace;
int use_stack;
int size = FTRACE_STACK_ENTRIES;
trace.nr_entries = 0;
trace.skip = skip;
tracing: Skip more functions when doing stack tracing of events # echo 1 > options/stacktrace # echo 1 > events/sched/sched_switch/enable # cat trace <idle>-0 [002] d..2 1982.525169: <stack trace> => save_stack_trace => __ftrace_trace_stack => trace_buffer_unlock_commit_regs => event_trigger_unlock_commit => trace_event_buffer_commit => trace_event_raw_event_sched_switch => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => start_secondary The above shows that we are seeing 6 functions before ever making it to the caller of the sched_switch event. # echo stacktrace > events/sched/sched_switch/trigger # cat trace <idle>-0 [002] d..3 2146.335208: <stack trace> => trace_event_buffer_commit => trace_event_raw_event_sched_switch => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => start_secondary The stacktrace trigger isn't as bad, because it adds its own skip to the stacktracing, but still has two events extra. One issue is that if the stacktrace passes its own "regs" then there should be no addition to the skip, as the regs will not include the functions being called. This was an issue that was fixed by commit 7717c6be6999 ("tracing: Fix stacktrace skip depth in trace_buffer_unlock_commit_regs()" as adding the skip number for kprobes made the probes not have any stack at all. But since this is only an issue when regs is being used, a skip should be added if regs is NULL. Now we have: # echo 1 > options/stacktrace # echo 1 > events/sched/sched_switch/enable # cat trace <idle>-0 [000] d..2 1297.676333: <stack trace> => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => rest_init => start_kernel => x86_64_start_reservations => x86_64_start_kernel # echo stacktrace > events/sched/sched_switch/trigger # cat trace <idle>-0 [002] d..3 1370.759745: <stack trace> => __schedule => schedule => schedule_preempt_disabled => cpu_startup_entry => start_secondary And kprobes are not touched. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-06-23 20:03:47 +02:00
/*
* Add two, for this function and the call to save_stack_trace()
* If regs is set, then these functions will not be in the way.
*/
if (!regs)
trace.skip += 2;
/*
* Since events can happen in NMIs there's no safe way to
* use the per cpu ftrace_stacks. We reserve it and if an interrupt
* or NMI comes in, it will just have to use the default
* FTRACE_STACK_SIZE.
*/
preempt_disable_notrace();
use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
/*
* We don't need any atomic variables, just a barrier.
* If an interrupt comes in, we don't care, because it would
* have exited and put the counter back to what we want.
* We just need a barrier to keep gcc from moving things
* around.
*/
barrier();
if (use_stack == 1) {
trace.entries = this_cpu_ptr(ftrace_stack.calls);
trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
if (regs)
save_stack_trace_regs(regs, &trace);
else
save_stack_trace(&trace);
if (trace.nr_entries > size)
size = trace.nr_entries;
} else
/* From now on, use_stack is a boolean */
use_stack = 0;
size *= sizeof(unsigned long);
event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
sizeof(*entry) + size, flags, pc);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
memset(&entry->caller, 0, size);
if (use_stack)
memcpy(&entry->caller, trace.entries,
trace.nr_entries * sizeof(unsigned long));
else {
trace.max_entries = FTRACE_STACK_ENTRIES;
trace.entries = entry->caller;
if (regs)
save_stack_trace_regs(regs, &trace);
else
save_stack_trace(&trace);
}
entry->size = trace.nr_entries;
tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:34:17 +02:00
if (!call_filter_check_discard(call, entry, buffer, event))
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
__buffer_unlock_commit(buffer, event);
out:
/* Again, don't let gcc optimize things here */
barrier();
__this_cpu_dec(ftrace_stack_reserve);
preempt_enable_notrace();
}
static inline void ftrace_trace_stack(struct trace_array *tr,
struct ring_buffer *buffer,
unsigned long flags,
int skip, int pc, struct pt_regs *regs)
{
if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
return;
__ftrace_trace_stack(buffer, flags, skip, pc, regs);
}
void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
int pc)
{
__ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
}
/**
* trace_dump_stack - record a stack back trace in the trace buffer
* @skip: Number of functions to skip (helper handlers)
*/
void trace_dump_stack(int skip)
{
unsigned long flags;
if (tracing_disabled || tracing_selftest_running)
return;
local_save_flags(flags);
/*
* Skip 3 more, seems to get us at the caller of
* this function.
*/
skip += 3;
__ftrace_trace_stack(global_trace.trace_buffer.buffer,
flags, skip, preempt_count(), NULL);
}
static DEFINE_PER_CPU(int, user_stack_count);
void
ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
{
struct trace_event_call *call = &event_user_stack;
struct ring_buffer_event *event;
struct userstack_entry *entry;
struct stack_trace trace;
if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE))
return;
tracing: Do not record user stack trace from NMI context A bug was found with Li Zefan's ftrace_stress_test that caused applications to segfault during the test. Placing a tracing_off() in the segfault code, and examining several traces, I found that the following was always the case. The lock tracer was enabled (lockdep being required) and userstack was enabled. Testing this out, I just enabled the two, but that was not good enough. I needed to run something else that could trigger it. Running a load like hackbench did not work, but executing a new program would. The following would trigger the segfault within seconds: # echo 1 > /debug/tracing/options/userstacktrace # echo 1 > /debug/tracing/events/lock/enable # while :; do ls > /dev/null ; done Enabling the function graph tracer and looking at what was happening I finally noticed that all cashes happened just after an NMI. 1) | copy_user_handle_tail() { 1) | bad_area_nosemaphore() { 1) | __bad_area_nosemaphore() { 1) | no_context() { 1) | fixup_exception() { 1) 0.319 us | search_exception_tables(); 1) 0.873 us | } [...] 1) 0.314 us | __rcu_read_unlock(); 1) 0.325 us | native_apic_mem_write(); 1) 0.943 us | } 1) 0.304 us | rcu_nmi_exit(); [...] 1) 0.479 us | find_vma(); 1) | bad_area() { 1) | __bad_area() { After capturing several traces of failures, all of them happened after an NMI. Curious about this, I added a trace_printk() to the NMI handler to read the regs->ip to see where the NMI happened. In which I found out it was here: ffffffff8135b660 <page_fault>: ffffffff8135b660: 48 83 ec 78 sub $0x78,%rsp ffffffff8135b664: e8 97 01 00 00 callq ffffffff8135b800 <error_entry> What was happening is that the NMI would happen at the place that a page fault occurred. It would call rcu_read_lock() which was traced by the lock events, and the user_stack_trace would run. This would trigger a page fault inside the NMI. I do not see where the CR2 register is saved or restored in NMI handling. This means that it would corrupt the page fault handling that the NMI interrupted. The reason the while loop of ls helped trigger the bug, was that each execution of ls would cause lots of pages to be faulted in, and increase the chances of the race happening. The simple solution is to not allow user stack traces in NMI context. After this patch, I ran the above "ls" test for a couple of hours without any issues. Without this patch, the bug would trigger in less than a minute. Cc: stable@kernel.org Reported-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-03-13 02:03:30 +01:00
/*
* NMIs can not handle page faults, even with fix ups.
* The save user stack can (and often does) fault.
*/
if (unlikely(in_nmi()))
return;
/*
* prevent recursion, since the user stack tracing may
* trigger other kernel events.
*/
preempt_disable();
if (__this_cpu_read(user_stack_count))
goto out;
__this_cpu_inc(user_stack_count);
event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
sizeof(*entry), flags, pc);
if (!event)
goto out_drop_count;
entry = ring_buffer_event_data(event);
entry->tgid = current->tgid;
memset(&entry->caller, 0, sizeof(entry->caller));
trace.nr_entries = 0;
trace.max_entries = FTRACE_STACK_ENTRIES;
trace.skip = 0;
trace.entries = entry->caller;
save_stack_trace_user(&trace);
tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:34:17 +02:00
if (!call_filter_check_discard(call, entry, buffer, event))
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
__buffer_unlock_commit(buffer, event);
out_drop_count:
__this_cpu_dec(user_stack_count);
out:
preempt_enable();
}
#ifdef UNUSED
static void __trace_userstack(struct trace_array *tr, unsigned long flags)
{
ftrace_trace_userstack(tr, flags, preempt_count());
}
#endif /* UNUSED */
#endif /* CONFIG_STACKTRACE */
2011-09-22 20:01:55 +02:00
/* created for use with alloc_percpu */
struct trace_buffer_struct {
int nesting;
char buffer[4][TRACE_BUF_SIZE];
2011-09-22 20:01:55 +02:00
};
static struct trace_buffer_struct *trace_percpu_buffer;
/*
* Thise allows for lockless recording. If we're nested too deeply, then
* this returns NULL.
2011-09-22 20:01:55 +02:00
*/
static char *get_trace_buf(void)
{
struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
2011-09-22 20:01:55 +02:00
if (!buffer || buffer->nesting >= 4)
2011-09-22 20:01:55 +02:00
return NULL;
return &buffer->buffer[buffer->nesting++][0];
}
static void put_trace_buf(void)
{
this_cpu_dec(trace_percpu_buffer->nesting);
2011-09-22 20:01:55 +02:00
}
static int alloc_percpu_trace_buffer(void)
{
struct trace_buffer_struct *buffers;
buffers = alloc_percpu(struct trace_buffer_struct);
if (WARN(!buffers, "Could not allocate percpu trace_printk buffer"))
return -ENOMEM;
2011-09-22 20:01:55 +02:00
trace_percpu_buffer = buffers;
return 0;
}
static int buffers_allocated;
2011-09-22 20:01:55 +02:00
void trace_printk_init_buffers(void)
{
if (buffers_allocated)
return;
if (alloc_percpu_trace_buffer())
return;
tracing: Print nasty banner when trace_printk() is in use trace_printk() is used to debug fast paths within the kernel. Places that gets called in any context (interrupt or NMI) or thousands of times a second. Something you do not want to do with a printk(). In order to make it completely lockless as it needs a temporary buffer to handle some of the string formatting, a page is created per cpu for every context (four per cpu; normal, softirq, irq, NMI). Since trace_printk() should only be used for debugging purposes, there's no reason to waste memory on these buffers on a production system. That means, trace_printk() should never be used unless a developer is debugging their kernel. There's macro magic to allocate the buffers if trace_printk() is used anywhere in the kernel. To help enforce that trace_printk() isn't used outside of development, when it is used, a nasty banner is displayed on bootup (or when a module is loaded that uses trace_printk() and the kernel core does not). Here's the banner: ********************************************************** ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** ** ** ** trace_printk() being used. Allocating extra memory. ** ** ** ** This means that this is a DEBUG kernel and it is ** ** unsafe for produciton use. ** ** ** ** If you see this message and you are not debugging ** ** the kernel, report this immediately to your vendor! ** ** ** ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** ********************************************************** That should hopefully keep developers from trying to sneak in a trace_printk() or two. Link: http://lkml.kernel.org/p/20140528131440.2283213c@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-28 19:14:40 +02:00
/* trace_printk() is for debug use only. Don't use it in production. */
pr_warn("\n");
pr_warn("**********************************************************\n");
pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
pr_warn("** **\n");
pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
pr_warn("** **\n");
pr_warn("** This means that this is a DEBUG kernel and it is **\n");
pr_warn("** unsafe for production use. **\n");
pr_warn("** **\n");
pr_warn("** If you see this message and you are not debugging **\n");
pr_warn("** the kernel, report this immediately to your vendor! **\n");
pr_warn("** **\n");
pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
pr_warn("**********************************************************\n");
2011-09-22 20:01:55 +02:00
/* Expand the buffers to set size */
tracing_update_buffers();
2011-09-22 20:01:55 +02:00
buffers_allocated = 1;
/*
* trace_printk_init_buffers() can be called by modules.
* If that happens, then we need to start cmdline recording
* directly here. If the global_trace.buffer is already
* allocated here, then this was called by module code.
*/
if (global_trace.trace_buffer.buffer)
tracing_start_cmdline_record();
}
void trace_printk_start_comm(void)
{
/* Start tracing comms if trace printk is set */
if (!buffers_allocated)
return;
tracing_start_cmdline_record();
}
static void trace_printk_start_stop_comm(int enabled)
{
if (!buffers_allocated)
return;
if (enabled)
tracing_start_cmdline_record();
else
tracing_stop_cmdline_record();
2011-09-22 20:01:55 +02:00
}
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
/**
* trace_vbprintk - write binary msg to tracing buffer
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
*
*/
int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
{
struct trace_event_call *call = &event_bprint;
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
struct ring_buffer_event *event;
struct ring_buffer *buffer;
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
struct trace_array *tr = &global_trace;
struct bprint_entry *entry;
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
unsigned long flags;
2011-09-22 20:01:55 +02:00
char *tbuffer;
int len = 0, size, pc;
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
if (unlikely(tracing_selftest_running || tracing_disabled))
return 0;
/* Don't pollute graph traces with trace_vprintk internals */
pause_graph_tracing();
pc = preempt_count();
tracing: Remove ftrace_preempt_disable/enable The ftrace_preempt_disable/enable functions were to address a recursive race caused by the function tracer. The function tracer traces all functions which makes it easily susceptible to recursion. One area was preempt_enable(). This would call the scheduler and the schedulre would call the function tracer and loop. (So was it thought). The ftrace_preempt_disable/enable was made to protect against recursion inside the scheduler by storing the NEED_RESCHED flag. If it was set before the ftrace_preempt_disable() it would not call schedule on ftrace_preempt_enable(), thinking that if it was set before then it would have already scheduled unless it was already in the scheduler. This worked fine except in the case of SMP, where another task would set the NEED_RESCHED flag for a task on another CPU, and then kick off an IPI to trigger it. This could cause the NEED_RESCHED to be saved at ftrace_preempt_disable() but the IPI to arrive in the the preempt disabled section. The ftrace_preempt_enable() would not call the scheduler because the flag was already set before entring the section. This bug would cause a missed preemption check and cause lower latencies. Investigating further, I found that the recusion caused by the function tracer was not due to schedule(), but due to preempt_schedule(). Now that preempt_schedule is completely annotated with notrace, the recusion no longer is an issue. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-03 15:36:50 +02:00
preempt_disable_notrace();
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
2011-09-22 20:01:55 +02:00
tbuffer = get_trace_buf();
if (!tbuffer) {
len = 0;
goto out_nobuffer;
2011-09-22 20:01:55 +02:00
}
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
2011-09-22 20:01:55 +02:00
len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
2011-09-22 20:01:55 +02:00
if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
goto out;
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
2011-09-22 20:01:55 +02:00
local_save_flags(flags);
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
size = sizeof(*entry) + sizeof(u32) * len;
buffer = tr->trace_buffer.buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
flags, pc);
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
if (!event)
2011-09-22 20:01:55 +02:00
goto out;
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->fmt = fmt;
2011-09-22 20:01:55 +02:00
memcpy(entry->buf, tbuffer, sizeof(u32) * len);
tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:34:17 +02:00
if (!call_filter_check_discard(call, entry, buffer, event)) {
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
__buffer_unlock_commit(buffer, event);
ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
}
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
out:
put_trace_buf();
out_nobuffer:
tracing: Remove ftrace_preempt_disable/enable The ftrace_preempt_disable/enable functions were to address a recursive race caused by the function tracer. The function tracer traces all functions which makes it easily susceptible to recursion. One area was preempt_enable(). This would call the scheduler and the schedulre would call the function tracer and loop. (So was it thought). The ftrace_preempt_disable/enable was made to protect against recursion inside the scheduler by storing the NEED_RESCHED flag. If it was set before the ftrace_preempt_disable() it would not call schedule on ftrace_preempt_enable(), thinking that if it was set before then it would have already scheduled unless it was already in the scheduler. This worked fine except in the case of SMP, where another task would set the NEED_RESCHED flag for a task on another CPU, and then kick off an IPI to trigger it. This could cause the NEED_RESCHED to be saved at ftrace_preempt_disable() but the IPI to arrive in the the preempt disabled section. The ftrace_preempt_enable() would not call the scheduler because the flag was already set before entring the section. This bug would cause a missed preemption check and cause lower latencies. Investigating further, I found that the recusion caused by the function tracer was not due to schedule(), but due to preempt_schedule(). Now that preempt_schedule is completely annotated with notrace, the recusion no longer is an issue. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-06-03 15:36:50 +02:00
preempt_enable_notrace();
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
unpause_graph_tracing();
return len;
}
EXPORT_SYMBOL_GPL(trace_vbprintk);
static int
__trace_array_vprintk(struct ring_buffer *buffer,
unsigned long ip, const char *fmt, va_list args)
{
struct trace_event_call *call = &event_print;
struct ring_buffer_event *event;
2011-09-22 20:01:55 +02:00
int len = 0, size, pc;
struct print_entry *entry;
2011-09-22 20:01:55 +02:00
unsigned long flags;
char *tbuffer;
if (tracing_disabled || tracing_selftest_running)
return 0;
2011-09-22 20:01:55 +02:00
/* Don't pollute graph traces with trace_vprintk internals */
pause_graph_tracing();
pc = preempt_count();
preempt_disable_notrace();
2011-09-22 20:01:55 +02:00
tbuffer = get_trace_buf();
if (!tbuffer) {
len = 0;
goto out_nobuffer;
2011-09-22 20:01:55 +02:00
}
len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
2011-09-22 20:01:55 +02:00
local_save_flags(flags);
size = sizeof(*entry) + len + 1;
event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
2011-09-22 20:01:55 +02:00
flags, pc);
if (!event)
2011-09-22 20:01:55 +02:00
goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
memcpy(&entry->buf, tbuffer, len + 1);
tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-10-24 15:34:17 +02:00
if (!call_filter_check_discard(call, entry, buffer, event)) {
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
__buffer_unlock_commit(buffer, event);
ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
}
out:
put_trace_buf();
out_nobuffer:
preempt_enable_notrace();
2011-09-22 20:01:55 +02:00
unpause_graph_tracing();
return len;
}
int trace_array_vprintk(struct trace_array *tr,
unsigned long ip, const char *fmt, va_list args)
{
return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
}
int trace_array_printk(struct trace_array *tr,
unsigned long ip, const char *fmt, ...)
{
int ret;
va_list ap;
if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
return 0;
va_start(ap, fmt);
ret = trace_array_vprintk(tr, ip, fmt, ap);
va_end(ap);
return ret;
}
int trace_array_printk_buf(struct ring_buffer *buffer,
unsigned long ip, const char *fmt, ...)
{
int ret;
va_list ap;
if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
return 0;
va_start(ap, fmt);
ret = __trace_array_vprintk(buffer, ip, fmt, ap);
va_end(ap);
return ret;
}
int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
{
return trace_array_vprintk(&global_trace, ip, fmt, args);
}
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:21:49 +01:00
EXPORT_SYMBOL_GPL(trace_vprintk);
static void trace_iterator_increment(struct trace_iterator *iter)
{
struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
iter->idx++;
if (buf_iter)
ring_buffer_read(buf_iter, NULL);
}
static struct trace_entry *
peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
unsigned long *lost_events)
{
struct ring_buffer_event *event;
struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
if (buf_iter)
event = ring_buffer_iter_peek(buf_iter, ts);
else
event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
lost_events);
if (event) {
iter->ent_size = ring_buffer_event_length(event);
return ring_buffer_event_data(event);
}
iter->ent_size = 0;
return NULL;
}
static struct trace_entry *
__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
unsigned long *missing_events, u64 *ent_ts)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct ring_buffer *buffer = iter->trace_buffer->buffer;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
struct trace_entry *ent, *next = NULL;
unsigned long lost_events = 0, next_lost = 0;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
int cpu_file = iter->cpu_file;
u64 next_ts = 0, ts;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int next_cpu = -1;
int next_size = 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int cpu;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
/*
* If we are in a per_cpu trace file, don't bother by iterating over
* all cpu and peek directly.
*/
if (cpu_file > RING_BUFFER_ALL_CPUS) {
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
if (ring_buffer_empty_cpu(buffer, cpu_file))
return NULL;
ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
if (ent_cpu)
*ent_cpu = cpu_file;
return ent;
}
for_each_tracing_cpu(cpu) {
if (ring_buffer_empty_cpu(buffer, cpu))
continue;
ent = peek_next_entry(iter, cpu, &ts, &lost_events);
/*
* Pick the entry with the smallest timestamp:
*/
if (ent && (!next || ts < next_ts)) {
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
next = ent;
next_cpu = cpu;
next_ts = ts;
next_lost = lost_events;
next_size = iter->ent_size;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
}
iter->ent_size = next_size;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (ent_cpu)
*ent_cpu = next_cpu;
if (ent_ts)
*ent_ts = next_ts;
if (missing_events)
*missing_events = next_lost;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return next;
}
/* Find the next real entry, without updating the iterator itself */
trace: better manage the context info for events Impact: make trace_event more convenient for tracers All tracers (for the moment) that use the struct trace_event want to have the context info printed before their own output: the pid/cmdline, cpu, and timestamp. But some other tracers that want to implement their trace_event callbacks will not necessary need these information or they may want to format them as they want. This patch adds a new default-enabled trace option: TRACE_ITER_CONTEXT_INFO When disabled through: echo nocontext-info > /debugfs/tracing/trace_options The pid, cpu and timestamps headers will not be printed. IE with the sched_switch tracer with context-info (default): bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle> <idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0 <idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0 events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle> Without context-info: 2935:120:S ==> [001] 0:140:R <idle> 0:140:R + [000] 11:115:S events/0 0:140:R ==> [000] 11:115:R events/0 11:115:S ==> [000] 0:140:R <idle> A tracer can disable it at runtime by clearing the bit TRACE_ITER_CONTEXT_INFO in trace_flags. The print routines were renamed to trace_print_context and trace_print_lat_context, so that they can be used by tracers if they want to use them for one of the trace_event callbacks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-02 23:29:21 +01:00
struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
int *ent_cpu, u64 *ent_ts)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
}
/* Find the next real entry, and increment the iterator to the next entry */
void *trace_find_next_entry_inc(struct trace_iterator *iter)
{
iter->ent = __find_next_entry(iter, &iter->cpu,
&iter->lost_events, &iter->ts);
if (iter->ent)
trace_iterator_increment(iter);
return iter->ent ? iter : NULL;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static void trace_consume(struct trace_iterator *iter)
{
ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
&iter->lost_events);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static void *s_next(struct seq_file *m, void *v, loff_t *pos)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct trace_iterator *iter = m->private;
int i = (int)*pos;
void *ent;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
tracing: Buffer the output of seq_file in case of filled buffer If the seq_read fills the buffer it will call s_start again on the next itertation with the same position. This causes a problem with the function_graph tracer because it consumes the iteration in order to determine leaf functions. What happens is that the iterator stores the entry, and the function graph plugin will look at the next entry. If that next entry is a return of the same function and task, then the function is a leaf and the function_graph plugin calls ring_buffer_read which moves the ring buffer iterator forward (the trace iterator still points to the function start entry). The copying of the trace_seq to the seq_file buffer will fail if the seq_file buffer is full. The seq_read will not show this entry. The next read by userspace will cause seq_read to again call s_start which will reuse the trace iterator entry (the function start entry). But the function return entry was already consumed. The function graph plugin will think that this entry is a nested function and not a leaf. To solve this, the trace code now checks the return status of the seq_printf (trace_print_seq). If the writing to the seq_file buffer fails, we set a flag in the iterator (leftover) and we do not reset the trace_seq buffer. On the next call to s_start, we check the leftover flag, and if it is set, we just reuse the trace_seq buffer and do not call into the plugin print functions. Before this patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) | __fsnotify_parent() { 2) 0.540 us | inotify_dentry_parent_queue_event(); After the patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) 0.548 us | __fsnotify_parent(); 2) 0.540 us | inotify_dentry_parent_queue_event(); [ Updated the patch to fix a missing return 0 from the trace_print_seq() stub when CONFIG_TRACING is disabled. Reported-by: Ingo Molnar <mingo@elte.hu> ] Reported-by: Jiri Olsa <jolsa@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-12-07 15:11:39 +01:00
WARN_ON_ONCE(iter->leftover);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
(*pos)++;
/* can't go backwards */
if (iter->idx > i)
return NULL;
if (iter->idx < 0)
ent = trace_find_next_entry_inc(iter);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
else
ent = iter;
while (ent && iter->idx < i)
ent = trace_find_next_entry_inc(iter);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
iter->pos = *pos;
return ent;
}
void tracing_iter_reset(struct trace_iterator *iter, int cpu)
{
struct ring_buffer_event *event;
struct ring_buffer_iter *buf_iter;
unsigned long entries = 0;
u64 ts;
per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
buf_iter = trace_buffer_iter(iter, cpu);
if (!buf_iter)
return;
ring_buffer_iter_reset(buf_iter);
/*
* We could have the case with the max latency tracers
* that a reset never took place on a cpu. This is evident
* by the timestamp being before the start of the buffer.
*/
while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
if (ts >= iter->trace_buffer->time_start)
break;
entries++;
ring_buffer_read(buf_iter, NULL);
}
per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
}
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
/*
* The current tracer is copied to avoid a global locking
* all around.
*/
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static void *s_start(struct seq_file *m, loff_t *pos)
{
struct trace_iterator *iter = m->private;
struct trace_array *tr = iter->tr;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
int cpu_file = iter->cpu_file;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
void *p = NULL;
loff_t l = 0;
int cpu;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/*
* copy the tracer to avoid using a global lock all around.
* iter->trace is a copy of current_trace, the pointer to the
* name may be used instead of a strcmp(), as iter->trace->name
* will point to the same string as current_trace->name.
*/
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_lock(&trace_types_lock);
if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
*iter->trace = *tr->current_trace;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_unlock(&trace_types_lock);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->trace->use_max_tr)
return ERR_PTR(-EBUSY);
#endif
if (!iter->snapshot)
atomic_inc(&trace_record_cmdline_disabled);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (*pos != iter->pos) {
iter->ent = NULL;
iter->cpu = 0;
iter->idx = -1;
if (cpu_file == RING_BUFFER_ALL_CPUS) {
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
for_each_tracing_cpu(cpu)
tracing_iter_reset(iter, cpu);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
} else
tracing_iter_reset(iter, cpu_file);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
iter->leftover = 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
for (p = iter; p && l < *pos; p = s_next(m, p, &l))
;
} else {
tracing: Buffer the output of seq_file in case of filled buffer If the seq_read fills the buffer it will call s_start again on the next itertation with the same position. This causes a problem with the function_graph tracer because it consumes the iteration in order to determine leaf functions. What happens is that the iterator stores the entry, and the function graph plugin will look at the next entry. If that next entry is a return of the same function and task, then the function is a leaf and the function_graph plugin calls ring_buffer_read which moves the ring buffer iterator forward (the trace iterator still points to the function start entry). The copying of the trace_seq to the seq_file buffer will fail if the seq_file buffer is full. The seq_read will not show this entry. The next read by userspace will cause seq_read to again call s_start which will reuse the trace iterator entry (the function start entry). But the function return entry was already consumed. The function graph plugin will think that this entry is a nested function and not a leaf. To solve this, the trace code now checks the return status of the seq_printf (trace_print_seq). If the writing to the seq_file buffer fails, we set a flag in the iterator (leftover) and we do not reset the trace_seq buffer. On the next call to s_start, we check the leftover flag, and if it is set, we just reuse the trace_seq buffer and do not call into the plugin print functions. Before this patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) | __fsnotify_parent() { 2) 0.540 us | inotify_dentry_parent_queue_event(); After the patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) 0.548 us | __fsnotify_parent(); 2) 0.540 us | inotify_dentry_parent_queue_event(); [ Updated the patch to fix a missing return 0 from the trace_print_seq() stub when CONFIG_TRACING is disabled. Reported-by: Ingo Molnar <mingo@elte.hu> ] Reported-by: Jiri Olsa <jolsa@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-12-07 15:11:39 +01:00
/*
* If we overflowed the seq_file before, then we want
* to just reuse the trace_seq buffer again.
*/
if (iter->leftover)
p = iter;
else {
l = *pos - 1;
p = s_next(m, p, &l);
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
trace_event_read_lock();
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
trace_access_lock(cpu_file);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return p;
}
static void s_stop(struct seq_file *m, void *p)
{
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
struct trace_iterator *iter = m->private;
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->trace->use_max_tr)
return;
#endif
if (!iter->snapshot)
atomic_dec(&trace_record_cmdline_disabled);
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
trace_access_unlock(iter->cpu_file);
trace_event_read_unlock();
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static void
get_total_entries(struct trace_buffer *buf,
unsigned long *total, unsigned long *entries)
{
unsigned long count;
int cpu;
*total = 0;
*entries = 0;
for_each_tracing_cpu(cpu) {
count = ring_buffer_entries_cpu(buf->buffer, cpu);
/*
* If this buffer has skipped entries, then we hold all
* entries for the trace and we need to ignore the
* ones before the time stamp.
*/
if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
/* total is the same as the entries */
*total += count;
} else
*total += count +
ring_buffer_overrun_cpu(buf->buffer, cpu);
*entries += count;
}
}
static void print_lat_help_header(struct seq_file *m)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
seq_puts(m, "# _------=> CPU# \n"
"# / _-----=> irqs-off \n"
"# | / _----=> need-resched \n"
"# || / _---=> hardirq/softirq \n"
"# ||| / _--=> preempt-depth \n"
"# |||| / delay \n"
"# cmd pid ||||| time | caller \n"
"# \\ / ||||| \\ | / \n");
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
unsigned long total;
unsigned long entries;
get_total_entries(buf, &total, &entries);
seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
entries, total, num_online_cpus());
seq_puts(m, "#\n");
}
static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
{
print_event_info(buf, m);
seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n"
"# | | | | |\n");
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
tracing: Add irq, preempt-count and need resched info to default trace output People keep asking how to get the preempt count, irq, and need resched info and we keep telling them to enable the latency format. Some developers think that traces without this info is completely useless, and for a lot of tasks it is useless. The first option was to enable the latency trace as the default format, but the header for the latency format is pretty useless for most tracers and it also does the timestamp in straight microseconds from the time the trace started. This is sometimes more difficult to read as the default trace is seconds from the start of boot up. Latency format: # tracer: nop # # nop latency trace v1.1.5 on 3.2.0-rc1-test+ # -------------------------------------------------------------------- # latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / migratio-6 0...2 41778231us+: rcu_note_context_switch <-__schedule migratio-6 0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch migratio-6 0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch migratio-6 0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule default format: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | migration/0-6 [000] 50.025810: rcu_note_context_switch <-__schedule migration/0-6 [000] 50.025812: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025813: rcu_sched_qs <-rcu_note_context_switch migration/0-6 [000] 50.025815: rcu_preempt_qs <-rcu_note_context_switch migration/0-6 [000] 50.025817: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025818: debug_lockdep_rcu_enabled <-__schedule migration/0-6 [000] 50.025820: debug_lockdep_rcu_enabled <-__schedule The latency format header has latency information that is pretty meaningless for most tracers. Although some of the header is useful, and we can add that later to the default format as well. What is really useful with the latency format is the irqs-off, need-resched hard/softirq context and the preempt count. This commit adds the option irq-info which is on by default that adds this information: # tracer: nop # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] d..2 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] d..2 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] d..2 49.309309: need_resched <-mwait_idle <idle>-0 [000] d..2 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] d..2 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] d..2 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] d..2 49.309315: need_resched <-mwait_idle If a user wants the old format, they can disable the 'irq-info' option: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <idle>-0 [000] 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] 49.309309: need_resched <-mwait_idle <idle>-0 [000] 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] 49.309315: need_resched <-mwait_idle Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-17 15:34:33 +01:00
{
print_event_info(buf, m);
seq_puts(m, "# _-----=> irqs-off\n"
"# / _----=> need-resched\n"
"# | / _---=> hardirq/softirq\n"
"# || / _--=> preempt-depth\n"
"# ||| / delay\n"
"# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n"
"# | | | |||| | |\n");
tracing: Add irq, preempt-count and need resched info to default trace output People keep asking how to get the preempt count, irq, and need resched info and we keep telling them to enable the latency format. Some developers think that traces without this info is completely useless, and for a lot of tasks it is useless. The first option was to enable the latency trace as the default format, but the header for the latency format is pretty useless for most tracers and it also does the timestamp in straight microseconds from the time the trace started. This is sometimes more difficult to read as the default trace is seconds from the start of boot up. Latency format: # tracer: nop # # nop latency trace v1.1.5 on 3.2.0-rc1-test+ # -------------------------------------------------------------------- # latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / migratio-6 0...2 41778231us+: rcu_note_context_switch <-__schedule migratio-6 0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch migratio-6 0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch migratio-6 0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule default format: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | migration/0-6 [000] 50.025810: rcu_note_context_switch <-__schedule migration/0-6 [000] 50.025812: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025813: rcu_sched_qs <-rcu_note_context_switch migration/0-6 [000] 50.025815: rcu_preempt_qs <-rcu_note_context_switch migration/0-6 [000] 50.025817: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025818: debug_lockdep_rcu_enabled <-__schedule migration/0-6 [000] 50.025820: debug_lockdep_rcu_enabled <-__schedule The latency format header has latency information that is pretty meaningless for most tracers. Although some of the header is useful, and we can add that later to the default format as well. What is really useful with the latency format is the irqs-off, need-resched hard/softirq context and the preempt count. This commit adds the option irq-info which is on by default that adds this information: # tracer: nop # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] d..2 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] d..2 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] d..2 49.309309: need_resched <-mwait_idle <idle>-0 [000] d..2 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] d..2 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] d..2 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] d..2 49.309315: need_resched <-mwait_idle If a user wants the old format, they can disable the 'irq-info' option: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <idle>-0 [000] 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] 49.309309: need_resched <-mwait_idle <idle>-0 [000] 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] 49.309315: need_resched <-mwait_idle Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-17 15:34:33 +01:00
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
void
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
print_trace_header(struct seq_file *m, struct trace_iterator *iter)
{
unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
struct trace_buffer *buf = iter->trace_buffer;
struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
struct tracer *type = iter->trace;
unsigned long entries;
unsigned long total;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
const char *name = "preemption";
name = type->name;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
get_total_entries(buf, &total, &entries);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
name, UTS_RELEASE);
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_puts(m, "# -----------------------------------"
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
"---------------------------------\n");
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
" (M:%s VP:%d, KP:%d, SP:%d HP:%d",
nsecs_to_usecs(data->saved_latency),
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
entries,
total,
buf->cpu,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#if defined(CONFIG_PREEMPT_NONE)
"server",
#elif defined(CONFIG_PREEMPT_VOLUNTARY)
"desktop",
#elif defined(CONFIG_PREEMPT)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
"preempt",
#else
"unknown",
#endif
/* These are reserved for later use */
0, 0, 0, 0);
#ifdef CONFIG_SMP
seq_printf(m, " #P:%d)\n", num_online_cpus());
#else
seq_puts(m, ")\n");
#endif
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_puts(m, "# -----------------\n");
seq_printf(m, "# | task: %.16s-%d "
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
"(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
data->comm, data->pid,
from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
data->policy, data->rt_priority);
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_puts(m, "# -----------------\n");
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (data->critical_start) {
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_puts(m, "# => started at: ");
seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
trace_print_seq(m, &iter->seq);
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_puts(m, "\n# => ended at: ");
seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
trace_print_seq(m, &iter->seq);
seq_puts(m, "\n#\n");
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
ftrace: tracing header should put '#' at the beginning of a line In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-08 05:12:43 +01:00
seq_puts(m, "#\n");
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static void test_cpu_buff_start(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct trace_array *tr = iter->tr;
if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
return;
if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
return;
if (iter->started && cpumask_test_cpu(iter->cpu, iter->started))
return;
if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
return;
if (iter->started)
cpumask_set_cpu(iter->cpu, iter->started);
tracing/ftrace: alloc the started cpumask for the trace file Impact: fix a crash while cat trace file Currently we are using a cpumask to remind each cpu where a trace occured. It lets us notice the user that a cpu just had its first trace. But on latest -tip we have the following crash once we cat the trace file: IP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 *pde = 00000000 Oops: 0000 [#1] PREEMPT SMP last sysfs file: /sys/class/net/eth0/carrier Pid: 3897, comm: cat Not tainted (2.6.29-tip-02825-g0f22972-dirty #81) EIP: 0060:[<c0270c4a>] EFLAGS: 00010297 CPU: 0 EIP is at print_trace_fmt+0x45/0xe7 EAX: 00000000 EBX: 00000000 ECX: c12d9e98 EDX: ccdb7010 ESI: d31f4000 EDI: 00322401 EBP: d31f3f10 ESP: d31f3efc DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Process cat (pid: 3897, ti=d31f2000 task=d3b3cf20 task.ti=d31f2000) Stack: d31f4080 ccdb7010 d31f4000 d691fe70 ccdb7010 d31f3f24 c0270e5c d31f4000 d691fe70 d31f4000 d31f3f34 c02718e8 c12d9e98 d691fe70 d31f3f70 c02bfc33 00001000 09130000 d3b46e00 d691fe98 00000000 00000079 00000001 00000000 Call Trace: [<c0270e5c>] ? print_trace_line+0x170/0x17c [<c02718e8>] ? s_show+0xa7/0xbd [<c02bfc33>] ? seq_read+0x24a/0x327 [<c02bf9e9>] ? seq_read+0x0/0x327 [<c02ab18b>] ? vfs_read+0x86/0xe1 [<c02ab289>] ? sys_read+0x40/0x65 [<c0202d8f>] ? sysenter_do_call+0x12/0x3c Code: 00 00 00 89 45 ec f7 c7 00 20 00 00 89 55 f0 74 4e f6 86 98 10 00 00 02 74 45 8b 86 8c 10 00 00 8b 9e a8 10 00 00 e8 52 f3 ff ff <0f> a3 03 19 c0 85 c0 75 2b 8b 86 8c 10 00 00 8b 9e a8 10 00 00 EIP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 SS:ESP 0068:d31f3efc CR2: 0000000000000000 ---[ end trace aa9cf38e5ebed9dd ]--- This is because we alloc the iter->started cpumask on tracing_pipe_open but not on tracing_open. It hadn't been noticed until now because we need to have ring buffer overruns to activate the starting of cpu buffer detection. Also, we need a check to not print the messagge for the first trace on the file. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1238619188-6109-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-01 22:53:08 +02:00
/* Don't print started cpu buffer for the first entry of the trace */
if (iter->idx > 1)
trace_seq_printf(s, "##### CPU %u buffer started ####\n",
iter->cpu);
}
static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct trace_array *tr = iter->tr;
struct trace_seq *s = &iter->seq;
unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
struct trace_entry *entry;
struct trace_event *event;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
entry = iter->ent;
test_cpu_buff_start(iter);
trace: better manage the context info for events Impact: make trace_event more convenient for tracers All tracers (for the moment) that use the struct trace_event want to have the context info printed before their own output: the pid/cmdline, cpu, and timestamp. But some other tracers that want to implement their trace_event callbacks will not necessary need these information or they may want to format them as they want. This patch adds a new default-enabled trace option: TRACE_ITER_CONTEXT_INFO When disabled through: echo nocontext-info > /debugfs/tracing/trace_options The pid, cpu and timestamps headers will not be printed. IE with the sched_switch tracer with context-info (default): bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle> <idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0 <idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0 events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle> Without context-info: 2935:120:S ==> [001] 0:140:R <idle> 0:140:R + [000] 11:115:S events/0 0:140:R ==> [000] 11:115:R events/0 11:115:S ==> [000] 0:140:R <idle> A tracer can disable it at runtime by clearing the bit TRACE_ITER_CONTEXT_INFO in trace_flags. The print routines were renamed to trace_print_context and trace_print_lat_context, so that they can be used by tracers if they want to use them for one of the trace_event callbacks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-02 23:29:21 +01:00
event = ftrace_find_event(entry->type);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
if (iter->iter_flags & TRACE_FILE_LAT_FMT)
trace_print_lat_context(iter);
else
trace_print_context(iter);
trace: better manage the context info for events Impact: make trace_event more convenient for tracers All tracers (for the moment) that use the struct trace_event want to have the context info printed before their own output: the pid/cmdline, cpu, and timestamp. But some other tracers that want to implement their trace_event callbacks will not necessary need these information or they may want to format them as they want. This patch adds a new default-enabled trace option: TRACE_ITER_CONTEXT_INFO When disabled through: echo nocontext-info > /debugfs/tracing/trace_options The pid, cpu and timestamps headers will not be printed. IE with the sched_switch tracer with context-info (default): bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle> <idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0 <idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0 events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle> Without context-info: 2935:120:S ==> [001] 0:140:R <idle> 0:140:R + [000] 11:115:S events/0 0:140:R ==> [000] 11:115:R events/0 11:115:S ==> [000] 0:140:R <idle> A tracer can disable it at runtime by clearing the bit TRACE_ITER_CONTEXT_INFO in trace_flags. The print routines were renamed to trace_print_context and trace_print_lat_context, so that they can be used by tracers if they want to use them for one of the trace_event callbacks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-02 23:29:21 +01:00
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (trace_seq_has_overflowed(s))
return TRACE_TYPE_PARTIAL_LINE;
if (event)
return event->funcs->trace(iter, sym_flags, event);
trace_seq_printf(s, "Unknown type %d\n", entry->type);
return trace_handle_return(s);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
{
struct trace_array *tr = iter->tr;
struct trace_seq *s = &iter->seq;
struct trace_entry *entry;
struct trace_event *event;
entry = iter->ent;
if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
trace_seq_printf(s, "%d %d %llu ",
entry->pid, iter->cpu, iter->ts);
if (trace_seq_has_overflowed(s))
return TRACE_TYPE_PARTIAL_LINE;
event = ftrace_find_event(entry->type);
if (event)
return event->funcs->raw(iter, 0, event);
trace_seq_printf(s, "%d ?\n", entry->type);
return trace_handle_return(s);
}
static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
{
struct trace_array *tr = iter->tr;
struct trace_seq *s = &iter->seq;
unsigned char newline = '\n';
struct trace_entry *entry;
struct trace_event *event;
entry = iter->ent;
if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
SEQ_PUT_HEX_FIELD(s, entry->pid);
SEQ_PUT_HEX_FIELD(s, iter->cpu);
SEQ_PUT_HEX_FIELD(s, iter->ts);
if (trace_seq_has_overflowed(s))
return TRACE_TYPE_PARTIAL_LINE;
trace: better manage the context info for events Impact: make trace_event more convenient for tracers All tracers (for the moment) that use the struct trace_event want to have the context info printed before their own output: the pid/cmdline, cpu, and timestamp. But some other tracers that want to implement their trace_event callbacks will not necessary need these information or they may want to format them as they want. This patch adds a new default-enabled trace option: TRACE_ITER_CONTEXT_INFO When disabled through: echo nocontext-info > /debugfs/tracing/trace_options The pid, cpu and timestamps headers will not be printed. IE with the sched_switch tracer with context-info (default): bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle> <idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0 <idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0 events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle> Without context-info: 2935:120:S ==> [001] 0:140:R <idle> 0:140:R + [000] 11:115:S events/0 0:140:R ==> [000] 11:115:R events/0 11:115:S ==> [000] 0:140:R <idle> A tracer can disable it at runtime by clearing the bit TRACE_ITER_CONTEXT_INFO in trace_flags. The print routines were renamed to trace_print_context and trace_print_lat_context, so that they can be used by tracers if they want to use them for one of the trace_event callbacks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-02 23:29:21 +01:00
}
event = ftrace_find_event(entry->type);
if (event) {
enum print_line_t ret = event->funcs->hex(iter, 0, event);
if (ret != TRACE_TYPE_HANDLED)
return ret;
}
SEQ_PUT_FIELD(s, newline);
return trace_handle_return(s);
}
static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
{
struct trace_array *tr = iter->tr;
struct trace_seq *s = &iter->seq;
struct trace_entry *entry;
struct trace_event *event;
entry = iter->ent;
if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
SEQ_PUT_FIELD(s, entry->pid);
SEQ_PUT_FIELD(s, iter->cpu);
SEQ_PUT_FIELD(s, iter->ts);
if (trace_seq_has_overflowed(s))
return TRACE_TYPE_PARTIAL_LINE;
trace: better manage the context info for events Impact: make trace_event more convenient for tracers All tracers (for the moment) that use the struct trace_event want to have the context info printed before their own output: the pid/cmdline, cpu, and timestamp. But some other tracers that want to implement their trace_event callbacks will not necessary need these information or they may want to format them as they want. This patch adds a new default-enabled trace option: TRACE_ITER_CONTEXT_INFO When disabled through: echo nocontext-info > /debugfs/tracing/trace_options The pid, cpu and timestamps headers will not be printed. IE with the sched_switch tracer with context-info (default): bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle> <idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0 <idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0 events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle> Without context-info: 2935:120:S ==> [001] 0:140:R <idle> 0:140:R + [000] 11:115:S events/0 0:140:R ==> [000] 11:115:R events/0 11:115:S ==> [000] 0:140:R <idle> A tracer can disable it at runtime by clearing the bit TRACE_ITER_CONTEXT_INFO in trace_flags. The print routines were renamed to trace_print_context and trace_print_lat_context, so that they can be used by tracers if they want to use them for one of the trace_event callbacks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-02 23:29:21 +01:00
}
event = ftrace_find_event(entry->type);
return event ? event->funcs->binary(iter, 0, event) :
TRACE_TYPE_HANDLED;
}
int trace_empty(struct trace_iterator *iter)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct ring_buffer_iter *buf_iter;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int cpu;
/* If we are looking at one CPU buffer, only check that one */
if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
cpu = iter->cpu_file;
buf_iter = trace_buffer_iter(iter, cpu);
if (buf_iter) {
if (!ring_buffer_iter_empty(buf_iter))
return 0;
} else {
if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
return 0;
}
return 1;
}
for_each_tracing_cpu(cpu) {
buf_iter = trace_buffer_iter(iter, cpu);
if (buf_iter) {
if (!ring_buffer_iter_empty(buf_iter))
return 0;
} else {
if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
return 0;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
return 1;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
/* Called with trace_event_read_lock() held. */
enum print_line_t print_trace_line(struct trace_iterator *iter)
{
struct trace_array *tr = iter->tr;
unsigned long trace_flags = tr->trace_flags;
enum print_line_t ret;
if (iter->lost_events) {
trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
iter->cpu, iter->lost_events);
if (trace_seq_has_overflowed(&iter->seq))
return TRACE_TYPE_PARTIAL_LINE;
}
if (iter->trace && iter->trace->print_line) {
ret = iter->trace->print_line(iter);
if (ret != TRACE_TYPE_UNHANDLED)
return ret;
}
if (iter->ent->type == TRACE_BPUTS &&
trace_flags & TRACE_ITER_PRINTK &&
trace_flags & TRACE_ITER_PRINTK_MSGONLY)
return trace_print_bputs_msg_only(iter);
if (iter->ent->type == TRACE_BPRINT &&
trace_flags & TRACE_ITER_PRINTK &&
trace_flags & TRACE_ITER_PRINTK_MSGONLY)
return trace_print_bprintk_msg_only(iter);
if (iter->ent->type == TRACE_PRINT &&
trace_flags & TRACE_ITER_PRINTK &&
trace_flags & TRACE_ITER_PRINTK_MSGONLY)
return trace_print_printk_msg_only(iter);
if (trace_flags & TRACE_ITER_BIN)
return print_bin_fmt(iter);
if (trace_flags & TRACE_ITER_HEX)
return print_hex_fmt(iter);
if (trace_flags & TRACE_ITER_RAW)
return print_raw_fmt(iter);
return print_trace_fmt(iter);
}
tracing/latency: Fix header output for latency tracers In case the the graph tracer (CONFIG_FUNCTION_GRAPH_TRACER) or even the function tracer (CONFIG_FUNCTION_TRACER) are not set, the latency tracers do not display proper latency header. The involved/fixed latency tracers are: wakeup_rt wakeup preemptirqsoff preemptoff irqsoff The patch adds proper handling of tracer configuration options for latency tracers, and displaying correct header info accordingly. * The current output (for wakeup tracer) with both graph and function tracers disabled is: # tracer: wakeup # <idle>-0 0d.h5 1us+: 0:120:R + [000] 7: 0:R watchdog/0 <idle>-0 0d.h5 3us+: ttwu_do_activate.clone.1 <-try_to_wake_up ... * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 55 us, #4/4, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: migration/0-6 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / cat-1129 0d..4 1us : 1129:120:R + [000] 6: 0:R migration/0 cat-1129 0d..4 2us+: ttwu_do_activate.clone.1 <-try_to_wake_up * The current output (for wakeup tracer) with only function tracer enabled is: # tracer: wakeup # cat-1140 0d..4 1us+: 1140:120:R + [000] 6: 0:R migration/0 cat-1140 0d..4 2us : ttwu_do_activate.clone.1 <-try_to_wake_up * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 207 us, #109/109, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: watchdog/1-12 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / <idle>-0 1d.h5 1us+: 0:120:R + [001] 12: 0:R watchdog/1 <idle>-0 1d.h5 3us : ttwu_do_activate.clone.1 <-try_to_wake_up Link: http://lkml.kernel.org/r/20111107150849.GE1807@m.brq.redhat.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 16:08:49 +01:00
void trace_latency_header(struct seq_file *m)
{
struct trace_iterator *iter = m->private;
struct trace_array *tr = iter->tr;
tracing/latency: Fix header output for latency tracers In case the the graph tracer (CONFIG_FUNCTION_GRAPH_TRACER) or even the function tracer (CONFIG_FUNCTION_TRACER) are not set, the latency tracers do not display proper latency header. The involved/fixed latency tracers are: wakeup_rt wakeup preemptirqsoff preemptoff irqsoff The patch adds proper handling of tracer configuration options for latency tracers, and displaying correct header info accordingly. * The current output (for wakeup tracer) with both graph and function tracers disabled is: # tracer: wakeup # <idle>-0 0d.h5 1us+: 0:120:R + [000] 7: 0:R watchdog/0 <idle>-0 0d.h5 3us+: ttwu_do_activate.clone.1 <-try_to_wake_up ... * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 55 us, #4/4, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: migration/0-6 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / cat-1129 0d..4 1us : 1129:120:R + [000] 6: 0:R migration/0 cat-1129 0d..4 2us+: ttwu_do_activate.clone.1 <-try_to_wake_up * The current output (for wakeup tracer) with only function tracer enabled is: # tracer: wakeup # cat-1140 0d..4 1us+: 1140:120:R + [000] 6: 0:R migration/0 cat-1140 0d..4 2us : ttwu_do_activate.clone.1 <-try_to_wake_up * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 207 us, #109/109, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: watchdog/1-12 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / <idle>-0 1d.h5 1us+: 0:120:R + [001] 12: 0:R watchdog/1 <idle>-0 1d.h5 3us : ttwu_do_activate.clone.1 <-try_to_wake_up Link: http://lkml.kernel.org/r/20111107150849.GE1807@m.brq.redhat.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 16:08:49 +01:00
/* print nothing if the buffers are empty */
if (trace_empty(iter))
return;
if (iter->iter_flags & TRACE_FILE_LAT_FMT)
print_trace_header(m, iter);
if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
tracing/latency: Fix header output for latency tracers In case the the graph tracer (CONFIG_FUNCTION_GRAPH_TRACER) or even the function tracer (CONFIG_FUNCTION_TRACER) are not set, the latency tracers do not display proper latency header. The involved/fixed latency tracers are: wakeup_rt wakeup preemptirqsoff preemptoff irqsoff The patch adds proper handling of tracer configuration options for latency tracers, and displaying correct header info accordingly. * The current output (for wakeup tracer) with both graph and function tracers disabled is: # tracer: wakeup # <idle>-0 0d.h5 1us+: 0:120:R + [000] 7: 0:R watchdog/0 <idle>-0 0d.h5 3us+: ttwu_do_activate.clone.1 <-try_to_wake_up ... * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 55 us, #4/4, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: migration/0-6 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / cat-1129 0d..4 1us : 1129:120:R + [000] 6: 0:R migration/0 cat-1129 0d..4 2us+: ttwu_do_activate.clone.1 <-try_to_wake_up * The current output (for wakeup tracer) with only function tracer enabled is: # tracer: wakeup # cat-1140 0d..4 1us+: 1140:120:R + [000] 6: 0:R migration/0 cat-1140 0d..4 2us : ttwu_do_activate.clone.1 <-try_to_wake_up * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 207 us, #109/109, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: watchdog/1-12 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / <idle>-0 1d.h5 1us+: 0:120:R + [001] 12: 0:R watchdog/1 <idle>-0 1d.h5 3us : ttwu_do_activate.clone.1 <-try_to_wake_up Link: http://lkml.kernel.org/r/20111107150849.GE1807@m.brq.redhat.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-07 16:08:49 +01:00
print_lat_help_header(m);
}
void trace_default_header(struct seq_file *m)
{
struct trace_iterator *iter = m->private;
struct trace_array *tr = iter->tr;
unsigned long trace_flags = tr->trace_flags;
if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
return;
if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
/* print nothing if the buffers are empty */
if (trace_empty(iter))
return;
print_trace_header(m, iter);
if (!(trace_flags & TRACE_ITER_VERBOSE))
print_lat_help_header(m);
} else {
tracing: Add irq, preempt-count and need resched info to default trace output People keep asking how to get the preempt count, irq, and need resched info and we keep telling them to enable the latency format. Some developers think that traces without this info is completely useless, and for a lot of tasks it is useless. The first option was to enable the latency trace as the default format, but the header for the latency format is pretty useless for most tracers and it also does the timestamp in straight microseconds from the time the trace started. This is sometimes more difficult to read as the default trace is seconds from the start of boot up. Latency format: # tracer: nop # # nop latency trace v1.1.5 on 3.2.0-rc1-test+ # -------------------------------------------------------------------- # latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / migratio-6 0...2 41778231us+: rcu_note_context_switch <-__schedule migratio-6 0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch migratio-6 0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch migratio-6 0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule default format: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | migration/0-6 [000] 50.025810: rcu_note_context_switch <-__schedule migration/0-6 [000] 50.025812: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025813: rcu_sched_qs <-rcu_note_context_switch migration/0-6 [000] 50.025815: rcu_preempt_qs <-rcu_note_context_switch migration/0-6 [000] 50.025817: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025818: debug_lockdep_rcu_enabled <-__schedule migration/0-6 [000] 50.025820: debug_lockdep_rcu_enabled <-__schedule The latency format header has latency information that is pretty meaningless for most tracers. Although some of the header is useful, and we can add that later to the default format as well. What is really useful with the latency format is the irqs-off, need-resched hard/softirq context and the preempt count. This commit adds the option irq-info which is on by default that adds this information: # tracer: nop # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] d..2 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] d..2 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] d..2 49.309309: need_resched <-mwait_idle <idle>-0 [000] d..2 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] d..2 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] d..2 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] d..2 49.309315: need_resched <-mwait_idle If a user wants the old format, they can disable the 'irq-info' option: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <idle>-0 [000] 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] 49.309309: need_resched <-mwait_idle <idle>-0 [000] 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] 49.309315: need_resched <-mwait_idle Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-17 15:34:33 +01:00
if (!(trace_flags & TRACE_ITER_VERBOSE)) {
if (trace_flags & TRACE_ITER_IRQ_INFO)
print_func_help_header_irq(iter->trace_buffer, m);
tracing: Add irq, preempt-count and need resched info to default trace output People keep asking how to get the preempt count, irq, and need resched info and we keep telling them to enable the latency format. Some developers think that traces without this info is completely useless, and for a lot of tasks it is useless. The first option was to enable the latency trace as the default format, but the header for the latency format is pretty useless for most tracers and it also does the timestamp in straight microseconds from the time the trace started. This is sometimes more difficult to read as the default trace is seconds from the start of boot up. Latency format: # tracer: nop # # nop latency trace v1.1.5 on 3.2.0-rc1-test+ # -------------------------------------------------------------------- # latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / migratio-6 0...2 41778231us+: rcu_note_context_switch <-__schedule migratio-6 0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch migratio-6 0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch migratio-6 0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule default format: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | migration/0-6 [000] 50.025810: rcu_note_context_switch <-__schedule migration/0-6 [000] 50.025812: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025813: rcu_sched_qs <-rcu_note_context_switch migration/0-6 [000] 50.025815: rcu_preempt_qs <-rcu_note_context_switch migration/0-6 [000] 50.025817: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025818: debug_lockdep_rcu_enabled <-__schedule migration/0-6 [000] 50.025820: debug_lockdep_rcu_enabled <-__schedule The latency format header has latency information that is pretty meaningless for most tracers. Although some of the header is useful, and we can add that later to the default format as well. What is really useful with the latency format is the irqs-off, need-resched hard/softirq context and the preempt count. This commit adds the option irq-info which is on by default that adds this information: # tracer: nop # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] d..2 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] d..2 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] d..2 49.309309: need_resched <-mwait_idle <idle>-0 [000] d..2 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] d..2 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] d..2 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] d..2 49.309315: need_resched <-mwait_idle If a user wants the old format, they can disable the 'irq-info' option: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <idle>-0 [000] 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] 49.309309: need_resched <-mwait_idle <idle>-0 [000] 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] 49.309315: need_resched <-mwait_idle Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-17 15:34:33 +01:00
else
print_func_help_header(iter->trace_buffer, m);
tracing: Add irq, preempt-count and need resched info to default trace output People keep asking how to get the preempt count, irq, and need resched info and we keep telling them to enable the latency format. Some developers think that traces without this info is completely useless, and for a lot of tasks it is useless. The first option was to enable the latency trace as the default format, but the header for the latency format is pretty useless for most tracers and it also does the timestamp in straight microseconds from the time the trace started. This is sometimes more difficult to read as the default trace is seconds from the start of boot up. Latency format: # tracer: nop # # nop latency trace v1.1.5 on 3.2.0-rc1-test+ # -------------------------------------------------------------------- # latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / migratio-6 0...2 41778231us+: rcu_note_context_switch <-__schedule migratio-6 0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch migratio-6 0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch migratio-6 0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule default format: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | migration/0-6 [000] 50.025810: rcu_note_context_switch <-__schedule migration/0-6 [000] 50.025812: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025813: rcu_sched_qs <-rcu_note_context_switch migration/0-6 [000] 50.025815: rcu_preempt_qs <-rcu_note_context_switch migration/0-6 [000] 50.025817: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025818: debug_lockdep_rcu_enabled <-__schedule migration/0-6 [000] 50.025820: debug_lockdep_rcu_enabled <-__schedule The latency format header has latency information that is pretty meaningless for most tracers. Although some of the header is useful, and we can add that later to the default format as well. What is really useful with the latency format is the irqs-off, need-resched hard/softirq context and the preempt count. This commit adds the option irq-info which is on by default that adds this information: # tracer: nop # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] d..2 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] d..2 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] d..2 49.309309: need_resched <-mwait_idle <idle>-0 [000] d..2 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] d..2 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] d..2 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] d..2 49.309315: need_resched <-mwait_idle If a user wants the old format, they can disable the 'irq-info' option: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <idle>-0 [000] 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] 49.309309: need_resched <-mwait_idle <idle>-0 [000] 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] 49.309315: need_resched <-mwait_idle Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-17 15:34:33 +01:00
}
}
}
static void test_ftrace_alive(struct seq_file *m)
{
if (!ftrace_is_dead())
return;
seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
"# MAY BE MISSING FUNCTION EVENTS\n");
}
#ifdef CONFIG_TRACER_MAX_TRACE
static void show_snapshot_main_help(struct seq_file *m)
{
seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
"# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
"# Takes a snapshot of the main buffer.\n"
"# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
"# (Doesn't have to be '2' works with any number that\n"
"# is not a '0' or '1')\n");
}
static void show_snapshot_percpu_help(struct seq_file *m)
{
seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
"# Takes a snapshot of the main buffer for this cpu.\n");
#else
seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
"# Must use main snapshot file to allocate.\n");
#endif
seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
"# (Doesn't have to be '2' works with any number that\n"
"# is not a '0' or '1')\n");
}
static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
{
if (iter->tr->allocated_snapshot)
seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
else
seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
seq_puts(m, "# Snapshot commands:\n");
if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
show_snapshot_main_help(m);
else
show_snapshot_percpu_help(m);
}
#else
/* Should never be called */
static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
#endif
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static int s_show(struct seq_file *m, void *v)
{
struct trace_iterator *iter = v;
tracing: Buffer the output of seq_file in case of filled buffer If the seq_read fills the buffer it will call s_start again on the next itertation with the same position. This causes a problem with the function_graph tracer because it consumes the iteration in order to determine leaf functions. What happens is that the iterator stores the entry, and the function graph plugin will look at the next entry. If that next entry is a return of the same function and task, then the function is a leaf and the function_graph plugin calls ring_buffer_read which moves the ring buffer iterator forward (the trace iterator still points to the function start entry). The copying of the trace_seq to the seq_file buffer will fail if the seq_file buffer is full. The seq_read will not show this entry. The next read by userspace will cause seq_read to again call s_start which will reuse the trace iterator entry (the function start entry). But the function return entry was already consumed. The function graph plugin will think that this entry is a nested function and not a leaf. To solve this, the trace code now checks the return status of the seq_printf (trace_print_seq). If the writing to the seq_file buffer fails, we set a flag in the iterator (leftover) and we do not reset the trace_seq buffer. On the next call to s_start, we check the leftover flag, and if it is set, we just reuse the trace_seq buffer and do not call into the plugin print functions. Before this patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) | __fsnotify_parent() { 2) 0.540 us | inotify_dentry_parent_queue_event(); After the patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) 0.548 us | __fsnotify_parent(); 2) 0.540 us | inotify_dentry_parent_queue_event(); [ Updated the patch to fix a missing return 0 from the trace_print_seq() stub when CONFIG_TRACING is disabled. Reported-by: Ingo Molnar <mingo@elte.hu> ] Reported-by: Jiri Olsa <jolsa@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-12-07 15:11:39 +01:00
int ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (iter->ent == NULL) {
if (iter->tr) {
seq_printf(m, "# tracer: %s\n", iter->trace->name);
seq_puts(m, "#\n");
test_ftrace_alive(m);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
if (iter->snapshot && trace_empty(iter))
print_snapshot_help(m, iter);
else if (iter->trace && iter->trace->print_header)
iter->trace->print_header(m);
else
trace_default_header(m);
tracing: Buffer the output of seq_file in case of filled buffer If the seq_read fills the buffer it will call s_start again on the next itertation with the same position. This causes a problem with the function_graph tracer because it consumes the iteration in order to determine leaf functions. What happens is that the iterator stores the entry, and the function graph plugin will look at the next entry. If that next entry is a return of the same function and task, then the function is a leaf and the function_graph plugin calls ring_buffer_read which moves the ring buffer iterator forward (the trace iterator still points to the function start entry). The copying of the trace_seq to the seq_file buffer will fail if the seq_file buffer is full. The seq_read will not show this entry. The next read by userspace will cause seq_read to again call s_start which will reuse the trace iterator entry (the function start entry). But the function return entry was already consumed. The function graph plugin will think that this entry is a nested function and not a leaf. To solve this, the trace code now checks the return status of the seq_printf (trace_print_seq). If the writing to the seq_file buffer fails, we set a flag in the iterator (leftover) and we do not reset the trace_seq buffer. On the next call to s_start, we check the leftover flag, and if it is set, we just reuse the trace_seq buffer and do not call into the plugin print functions. Before this patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) | __fsnotify_parent() { 2) 0.540 us | inotify_dentry_parent_queue_event(); After the patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) 0.548 us | __fsnotify_parent(); 2) 0.540 us | inotify_dentry_parent_queue_event(); [ Updated the patch to fix a missing return 0 from the trace_print_seq() stub when CONFIG_TRACING is disabled. Reported-by: Ingo Molnar <mingo@elte.hu> ] Reported-by: Jiri Olsa <jolsa@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-12-07 15:11:39 +01:00
} else if (iter->leftover) {
/*
* If we filled the seq_file buffer earlier, we
* want to just show it now.
*/
ret = trace_print_seq(m, &iter->seq);
/* ret should this time be zero, but you never know */
iter->leftover = ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
} else {
print_trace_line(iter);
tracing: Buffer the output of seq_file in case of filled buffer If the seq_read fills the buffer it will call s_start again on the next itertation with the same position. This causes a problem with the function_graph tracer because it consumes the iteration in order to determine leaf functions. What happens is that the iterator stores the entry, and the function graph plugin will look at the next entry. If that next entry is a return of the same function and task, then the function is a leaf and the function_graph plugin calls ring_buffer_read which moves the ring buffer iterator forward (the trace iterator still points to the function start entry). The copying of the trace_seq to the seq_file buffer will fail if the seq_file buffer is full. The seq_read will not show this entry. The next read by userspace will cause seq_read to again call s_start which will reuse the trace iterator entry (the function start entry). But the function return entry was already consumed. The function graph plugin will think that this entry is a nested function and not a leaf. To solve this, the trace code now checks the return status of the seq_printf (trace_print_seq). If the writing to the seq_file buffer fails, we set a flag in the iterator (leftover) and we do not reset the trace_seq buffer. On the next call to s_start, we check the leftover flag, and if it is set, we just reuse the trace_seq buffer and do not call into the plugin print functions. Before this patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) | __fsnotify_parent() { 2) 0.540 us | inotify_dentry_parent_queue_event(); After the patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) 0.548 us | __fsnotify_parent(); 2) 0.540 us | inotify_dentry_parent_queue_event(); [ Updated the patch to fix a missing return 0 from the trace_print_seq() stub when CONFIG_TRACING is disabled. Reported-by: Ingo Molnar <mingo@elte.hu> ] Reported-by: Jiri Olsa <jolsa@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-12-07 15:11:39 +01:00
ret = trace_print_seq(m, &iter->seq);
/*
* If we overflow the seq_file buffer, then it will
* ask us for this data again at start up.
* Use that instead.
* ret is 0 if seq_file write succeeded.
* -1 otherwise.
*/
iter->leftover = ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
return 0;
}
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
/*
* Should be used after trace_array_get(), trace_types_lock
* ensures that i_cdev was already initialized.
*/
static inline int tracing_get_cpu(struct inode *inode)
{
if (inode->i_cdev) /* See trace_create_cpu_file() */
return (long)inode->i_cdev - 1;
return RING_BUFFER_ALL_CPUS;
}
static const struct seq_operations tracer_seq_ops = {
.start = s_start,
.next = s_next,
.stop = s_stop,
.show = s_show,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
static struct trace_iterator *
__tracing_open(struct inode *inode, struct file *file, bool snapshot)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct trace_array *tr = inode->i_private;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
struct trace_iterator *iter;
int cpu;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (tracing_disabled)
return ERR_PTR(-ENODEV);
iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
if (!iter)
return ERR_PTR(-ENOMEM);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
2015-06-09 09:32:35 +02:00
iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
GFP_KERNEL);
if (!iter->buffer_iter)
goto release;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
/*
* We make a copy of the current tracer to avoid concurrent
* changes on it while we are reading.
*/
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_lock(&trace_types_lock);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
if (!iter->trace)
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
goto fail;
*iter->trace = *tr->current_trace;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
tracing/ftrace: alloc the started cpumask for the trace file Impact: fix a crash while cat trace file Currently we are using a cpumask to remind each cpu where a trace occured. It lets us notice the user that a cpu just had its first trace. But on latest -tip we have the following crash once we cat the trace file: IP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 *pde = 00000000 Oops: 0000 [#1] PREEMPT SMP last sysfs file: /sys/class/net/eth0/carrier Pid: 3897, comm: cat Not tainted (2.6.29-tip-02825-g0f22972-dirty #81) EIP: 0060:[<c0270c4a>] EFLAGS: 00010297 CPU: 0 EIP is at print_trace_fmt+0x45/0xe7 EAX: 00000000 EBX: 00000000 ECX: c12d9e98 EDX: ccdb7010 ESI: d31f4000 EDI: 00322401 EBP: d31f3f10 ESP: d31f3efc DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Process cat (pid: 3897, ti=d31f2000 task=d3b3cf20 task.ti=d31f2000) Stack: d31f4080 ccdb7010 d31f4000 d691fe70 ccdb7010 d31f3f24 c0270e5c d31f4000 d691fe70 d31f4000 d31f3f34 c02718e8 c12d9e98 d691fe70 d31f3f70 c02bfc33 00001000 09130000 d3b46e00 d691fe98 00000000 00000079 00000001 00000000 Call Trace: [<c0270e5c>] ? print_trace_line+0x170/0x17c [<c02718e8>] ? s_show+0xa7/0xbd [<c02bfc33>] ? seq_read+0x24a/0x327 [<c02bf9e9>] ? seq_read+0x0/0x327 [<c02ab18b>] ? vfs_read+0x86/0xe1 [<c02ab289>] ? sys_read+0x40/0x65 [<c0202d8f>] ? sysenter_do_call+0x12/0x3c Code: 00 00 00 89 45 ec f7 c7 00 20 00 00 89 55 f0 74 4e f6 86 98 10 00 00 02 74 45 8b 86 8c 10 00 00 8b 9e a8 10 00 00 e8 52 f3 ff ff <0f> a3 03 19 c0 85 c0 75 2b 8b 86 8c 10 00 00 8b 9e a8 10 00 00 EIP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 SS:ESP 0068:d31f3efc CR2: 0000000000000000 ---[ end trace aa9cf38e5ebed9dd ]--- This is because we alloc the iter->started cpumask on tracing_pipe_open but not on tracing_open. It hadn't been noticed until now because we need to have ring buffer overruns to activate the starting of cpu buffer detection. Also, we need a check to not print the messagge for the first trace on the file. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1238619188-6109-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-01 22:53:08 +02:00
goto fail;
iter->tr = tr;
#ifdef CONFIG_TRACER_MAX_TRACE
/* Currently only the top directory has a snapshot */
if (tr->current_trace->print_max || snapshot)
iter->trace_buffer = &tr->max_buffer;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
else
#endif
iter->trace_buffer = &tr->trace_buffer;
iter->snapshot = snapshot;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
iter->pos = -1;
iter->cpu_file = tracing_get_cpu(inode);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_init(&iter->mutex);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/* Notify the tracer early; before we stop tracing. */
if (iter->trace && iter->trace->open)
iter->trace->open(iter);
/* Annotate start of buffers if we had overruns */
if (ring_buffer_overruns(iter->trace_buffer->buffer))
iter->iter_flags |= TRACE_FILE_ANNOTATE;
tracing: Format non-nanosec times from tsc clock without a decimal point. With the addition of the "tsc" clock, formatting timestamps to look like fractional seconds is misleading. Mark clocks as either in nanoseconds or not, and format non-nanosecond timestamps as decimal integers. Tested: $ cd /sys/kernel/debug/tracing/ $ cat trace_clock [local] global tsc $ echo sched_switch > set_event $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ cat trace <idle>-0 [000] 6330.555552: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 [000] 6330.555628: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo 1 > options/latency-format $ cat trace <idle>-0 0 4104553247us+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 0 4104553322us+: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo tsc > trace_clock $ cat trace $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ echo 0 > options/latency-format $ cat trace <idle>-0 [000] 16490053398357: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 [000] 16490053588518: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... echo 1 > options/latency-format $ cat trace <idle>-0 0 91557653238+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 0 91557843399+: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... v2: Move arch-specific bits out of generic code. v4: Fix x86_32 build due to 64-bit division. Google-Bug-Id: 6980623 Link: http://lkml.kernel.org/r/1352837903-32191-2-git-send-email-dhsharp@google.com Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: David Sharp <dhsharp@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-13 21:18:22 +01:00
/* Output in nanoseconds only if we are using a clock in nanoseconds. */
if (trace_clocks[tr->clock_id].in_ns)
tracing: Format non-nanosec times from tsc clock without a decimal point. With the addition of the "tsc" clock, formatting timestamps to look like fractional seconds is misleading. Mark clocks as either in nanoseconds or not, and format non-nanosecond timestamps as decimal integers. Tested: $ cd /sys/kernel/debug/tracing/ $ cat trace_clock [local] global tsc $ echo sched_switch > set_event $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ cat trace <idle>-0 [000] 6330.555552: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 [000] 6330.555628: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo 1 > options/latency-format $ cat trace <idle>-0 0 4104553247us+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 0 4104553322us+: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo tsc > trace_clock $ cat trace $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ echo 0 > options/latency-format $ cat trace <idle>-0 [000] 16490053398357: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 [000] 16490053588518: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... echo 1 > options/latency-format $ cat trace <idle>-0 0 91557653238+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 0 91557843399+: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... v2: Move arch-specific bits out of generic code. v4: Fix x86_32 build due to 64-bit division. Google-Bug-Id: 6980623 Link: http://lkml.kernel.org/r/1352837903-32191-2-git-send-email-dhsharp@google.com Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: David Sharp <dhsharp@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-13 21:18:22 +01:00
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
/* stop the trace while dumping if we are not opening "snapshot" */
if (!iter->snapshot)
tracing_stop_tr(tr);
if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
for_each_tracing_cpu(cpu) {
iter->buffer_iter[cpu] =
ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
ring-buffer: Make non-consuming read less expensive with lots of cpus. When performing a non-consuming read, a synchronize_sched() is performed once for every cpu which is actively tracing. This is very expensive, and can make it take several seconds to open up the 'trace' file with lots of cpus. Only one synchronize_sched() call is actually necessary. What is desired is for all cpus to see the disabling state change. So we transform the existing sequence: for_each_cpu() { ring_buffer_read_start(); } where each ring_buffer_start() call performs a synchronize_sched(), into the following: for_each_cpu() { ring_buffer_read_prepare(); } ring_buffer_read_prepare_sync(); for_each_cpu() { ring_buffer_read_start(); } wherein only the single ring_buffer_read_prepare_sync() call needs to do the synchronize_sched(). The first phase, via ring_buffer_read_prepare(), allocates the 'iter' memory and increments ->record_disabled. In the second phase, ring_buffer_read_prepare_sync() makes sure this ->record_disabled state is visible fully to all cpus. And in the final third phase, the ring_buffer_read_start() calls reset the 'iter' objects allocated in the first phase since we now know that none of the cpus are adding trace entries any more. This makes openning the 'trace' file nearly instantaneous on a sparc64 Niagara2 box with 128 cpus tracing. Signed-off-by: David S. Miller <davem@davemloft.net> LKML-Reference: <20100420.154711.11246950.davem@davemloft.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-04-21 00:47:11 +02:00
}
ring_buffer_read_prepare_sync();
for_each_tracing_cpu(cpu) {
ring_buffer_read_start(iter->buffer_iter[cpu]);
tracing_iter_reset(iter, cpu);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
}
} else {
cpu = iter->cpu_file;
iter->buffer_iter[cpu] =
ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
ring-buffer: Make non-consuming read less expensive with lots of cpus. When performing a non-consuming read, a synchronize_sched() is performed once for every cpu which is actively tracing. This is very expensive, and can make it take several seconds to open up the 'trace' file with lots of cpus. Only one synchronize_sched() call is actually necessary. What is desired is for all cpus to see the disabling state change. So we transform the existing sequence: for_each_cpu() { ring_buffer_read_start(); } where each ring_buffer_start() call performs a synchronize_sched(), into the following: for_each_cpu() { ring_buffer_read_prepare(); } ring_buffer_read_prepare_sync(); for_each_cpu() { ring_buffer_read_start(); } wherein only the single ring_buffer_read_prepare_sync() call needs to do the synchronize_sched(). The first phase, via ring_buffer_read_prepare(), allocates the 'iter' memory and increments ->record_disabled. In the second phase, ring_buffer_read_prepare_sync() makes sure this ->record_disabled state is visible fully to all cpus. And in the final third phase, the ring_buffer_read_start() calls reset the 'iter' objects allocated in the first phase since we now know that none of the cpus are adding trace entries any more. This makes openning the 'trace' file nearly instantaneous on a sparc64 Niagara2 box with 128 cpus tracing. Signed-off-by: David S. Miller <davem@davemloft.net> LKML-Reference: <20100420.154711.11246950.davem@davemloft.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-04-21 00:47:11 +02:00
ring_buffer_read_prepare_sync();
ring_buffer_read_start(iter->buffer_iter[cpu]);
tracing_iter_reset(iter, cpu);
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_unlock(&trace_types_lock);
return iter;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
fail:
mutex_unlock(&trace_types_lock);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
kfree(iter->trace);
kfree(iter->buffer_iter);
release:
seq_release_private(inode, file);
return ERR_PTR(-ENOMEM);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
int tracing_open_generic(struct inode *inode, struct file *filp)
{
if (tracing_disabled)
return -ENODEV;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
filp->private_data = inode->i_private;
return 0;
}
bool tracing_is_disabled(void)
{
return (tracing_disabled) ? true: false;
}
/*
* Open and update trace_array ref count.
* Must have the current trace_array passed to it.
*/
static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
{
struct trace_array *tr = inode->i_private;
if (tracing_disabled)
return -ENODEV;
if (trace_array_get(tr) < 0)
return -ENODEV;
filp->private_data = inode->i_private;
return 0;
}
static int tracing_release(struct inode *inode, struct file *file)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct trace_array *tr = inode->i_private;
struct seq_file *m = file->private_data;
struct trace_iterator *iter;
int cpu;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (!(file->f_mode & FMODE_READ)) {
trace_array_put(tr);
return 0;
}
/* Writes do not use seq_file */
iter = m->private;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_lock(&trace_types_lock);
for_each_tracing_cpu(cpu) {
if (iter->buffer_iter[cpu])
ring_buffer_read_finish(iter->buffer_iter[cpu]);
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (iter->trace && iter->trace->close)
iter->trace->close(iter);
if (!iter->snapshot)
/* reenable tracing if it was previously enabled */
tracing_start_tr(tr);
__trace_array_put(tr);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_unlock(&trace_types_lock);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_destroy(&iter->mutex);
tracing/ftrace: alloc the started cpumask for the trace file Impact: fix a crash while cat trace file Currently we are using a cpumask to remind each cpu where a trace occured. It lets us notice the user that a cpu just had its first trace. But on latest -tip we have the following crash once we cat the trace file: IP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 *pde = 00000000 Oops: 0000 [#1] PREEMPT SMP last sysfs file: /sys/class/net/eth0/carrier Pid: 3897, comm: cat Not tainted (2.6.29-tip-02825-g0f22972-dirty #81) EIP: 0060:[<c0270c4a>] EFLAGS: 00010297 CPU: 0 EIP is at print_trace_fmt+0x45/0xe7 EAX: 00000000 EBX: 00000000 ECX: c12d9e98 EDX: ccdb7010 ESI: d31f4000 EDI: 00322401 EBP: d31f3f10 ESP: d31f3efc DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Process cat (pid: 3897, ti=d31f2000 task=d3b3cf20 task.ti=d31f2000) Stack: d31f4080 ccdb7010 d31f4000 d691fe70 ccdb7010 d31f3f24 c0270e5c d31f4000 d691fe70 d31f4000 d31f3f34 c02718e8 c12d9e98 d691fe70 d31f3f70 c02bfc33 00001000 09130000 d3b46e00 d691fe98 00000000 00000079 00000001 00000000 Call Trace: [<c0270e5c>] ? print_trace_line+0x170/0x17c [<c02718e8>] ? s_show+0xa7/0xbd [<c02bfc33>] ? seq_read+0x24a/0x327 [<c02bf9e9>] ? seq_read+0x0/0x327 [<c02ab18b>] ? vfs_read+0x86/0xe1 [<c02ab289>] ? sys_read+0x40/0x65 [<c0202d8f>] ? sysenter_do_call+0x12/0x3c Code: 00 00 00 89 45 ec f7 c7 00 20 00 00 89 55 f0 74 4e f6 86 98 10 00 00 02 74 45 8b 86 8c 10 00 00 8b 9e a8 10 00 00 e8 52 f3 ff ff <0f> a3 03 19 c0 85 c0 75 2b 8b 86 8c 10 00 00 8b 9e a8 10 00 00 EIP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 SS:ESP 0068:d31f3efc CR2: 0000000000000000 ---[ end trace aa9cf38e5ebed9dd ]--- This is because we alloc the iter->started cpumask on tracing_pipe_open but not on tracing_open. It hadn't been noticed until now because we need to have ring buffer overruns to activate the starting of cpu buffer detection. Also, we need a check to not print the messagge for the first trace on the file. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1238619188-6109-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-01 22:53:08 +02:00
free_cpumask_var(iter->started);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
kfree(iter->trace);
kfree(iter->buffer_iter);
seq_release_private(inode, file);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return 0;
}
static int tracing_release_generic_tr(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
trace_array_put(tr);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return 0;
}
static int tracing_single_release_tr(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
trace_array_put(tr);
return single_release(inode, file);
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static int tracing_open(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
int ret = 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (trace_array_get(tr) < 0)
return -ENODEV;
/* If this file was open for write, then erase contents */
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
int cpu = tracing_get_cpu(inode);
if (cpu == RING_BUFFER_ALL_CPUS)
tracing_reset_online_cpus(&tr->trace_buffer);
else
tracing_reset(&tr->trace_buffer, cpu);
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (file->f_mode & FMODE_READ) {
iter = __tracing_open(inode, file, false);
if (IS_ERR(iter))
ret = PTR_ERR(iter);
else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
iter->iter_flags |= TRACE_FILE_LAT_FMT;
}
if (ret < 0)
trace_array_put(tr);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return ret;
}
/*
* Some tracers are not suitable for instance buffers.
* A tracer is always available for the global array (toplevel)
* or if it explicitly states that it is.
*/
static bool
trace_ok_for_array(struct tracer *t, struct trace_array *tr)
{
return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
}
/* Find the next tracer that this trace array may use */
static struct tracer *
get_tracer_for_array(struct trace_array *tr, struct tracer *t)
{
while (t && !trace_ok_for_array(t, tr))
t = t->next;
return t;
}
static void *
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct trace_array *tr = m->private;
struct tracer *t = v;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
(*pos)++;
if (t)
t = get_tracer_for_array(tr, t->next);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return t;
}
static void *t_start(struct seq_file *m, loff_t *pos)
{
struct trace_array *tr = m->private;
struct tracer *t;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
loff_t l = 0;
mutex_lock(&trace_types_lock);
t = get_tracer_for_array(tr, trace_types);
for (; t && l < *pos; t = t_next(m, t, &l))
;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return t;
}
static void t_stop(struct seq_file *m, void *p)
{
mutex_unlock(&trace_types_lock);
}
static int t_show(struct seq_file *m, void *v)
{
struct tracer *t = v;
if (!t)
return 0;
seq_puts(m, t->name);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (t->next)
seq_putc(m, ' ');
else
seq_putc(m, '\n');
return 0;
}
static const struct seq_operations show_traces_seq_ops = {
.start = t_start,
.next = t_next,
.stop = t_stop,
.show = t_show,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
static int show_traces_open(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
struct seq_file *m;
int ret;
if (tracing_disabled)
return -ENODEV;
ret = seq_open(file, &show_traces_seq_ops);
if (ret)
return ret;
m = file->private_data;
m->private = tr;
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static ssize_t
tracing_write_stub(struct file *filp, const char __user *ubuf,
size_t count, loff_t *ppos)
{
return count;
}
loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
{
int ret;
if (file->f_mode & FMODE_READ)
ret = seq_lseek(file, offset, whence);
else
file->f_pos = ret = 0;
return ret;
}
static const struct file_operations tracing_fops = {
.open = tracing_open,
.read = seq_read,
.write = tracing_write_stub,
.llseek = tracing_lseek,
.release = tracing_release,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
static const struct file_operations show_traces_fops = {
.open = show_traces_open,
.read = seq_read,
.release = seq_release,
.llseek = seq_lseek,
};
/*
* The tracer itself will not take this lock, but still we want
* to provide a consistent cpumask to user-space:
*/
static DEFINE_MUTEX(tracing_cpumask_update_lock);
/*
* Temporary storage for the character representation of the
* CPU bitmask (and one more byte for the newline):
*/
static char mask_str[NR_CPUS + 1];
static ssize_t
tracing_cpumask_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct trace_array *tr = file_inode(filp)->i_private;
int len;
mutex_lock(&tracing_cpumask_update_lock);
len = snprintf(mask_str, count, "%*pb\n",
cpumask_pr_args(tr->tracing_cpumask));
if (len >= count) {
count = -EINVAL;
goto out_err;
}
count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
out_err:
mutex_unlock(&tracing_cpumask_update_lock);
return count;
}
static ssize_t
tracing_cpumask_write(struct file *filp, const char __user *ubuf,
size_t count, loff_t *ppos)
{
struct trace_array *tr = file_inode(filp)->i_private;
cpumask_var_t tracing_cpumask_new;
int err, cpu;
if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
return -ENOMEM;
err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
if (err)
goto err_unlock;
mutex_lock(&tracing_cpumask_update_lock);
local_irq_disable();
arch_spin_lock(&tr->max_lock);
for_each_tracing_cpu(cpu) {
/*
* Increase/decrease the disabled counter if we are
* about to flip a bit in the cpumask:
*/
if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
}
if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
cpumask_test_cpu(cpu, tracing_cpumask_new)) {
atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
}
}
arch_spin_unlock(&tr->max_lock);
local_irq_enable();
cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
mutex_unlock(&tracing_cpumask_update_lock);
free_cpumask_var(tracing_cpumask_new);
return count;
err_unlock:
free_cpumask_var(tracing_cpumask_new);
return err;
}
static const struct file_operations tracing_cpumask_fops = {
.open = tracing_open_generic_tr,
.read = tracing_cpumask_read,
.write = tracing_cpumask_write,
.release = tracing_release_generic_tr,
.llseek = generic_file_llseek,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
static int tracing_trace_options_show(struct seq_file *m, void *v)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct tracer_opt *trace_opts;
struct trace_array *tr = m->private;
u32 tracer_flags;
int i;
mutex_lock(&trace_types_lock);
tracer_flags = tr->current_trace->flags->val;
trace_opts = tr->current_trace->flags->opts;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
for (i = 0; trace_options[i]; i++) {
if (tr->trace_flags & (1 << i))
seq_printf(m, "%s\n", trace_options[i]);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
else
seq_printf(m, "no%s\n", trace_options[i]);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
for (i = 0; trace_opts[i].name; i++) {
if (tracer_flags & trace_opts[i].bit)
seq_printf(m, "%s\n", trace_opts[i].name);
else
seq_printf(m, "no%s\n", trace_opts[i].name);
}
mutex_unlock(&trace_types_lock);
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static int __set_tracer_option(struct trace_array *tr,
struct tracer_flags *tracer_flags,
struct tracer_opt *opts, int neg)
{
tracing: Make tracer_flags use the right set_flag callback When I was updating the ftrace_stress test of ltp. I encountered a strange phenomemon, excute following steps: echo nop > /sys/kernel/debug/tracing/current_tracer echo 0 > /sys/kernel/debug/tracing/options/funcgraph-cpu bash: echo: write error: Invalid argument check dmesg: [ 1024.903855] nop_test_refuse flag set to 0: we refuse.Now cat trace_options to see the result The reason is that the trace option test will randomly setup trace option under tracing/options no matter what the current_tracer is. but the set_tracer_option is always using the set_flag callback from the current_tracer. This patch adds a pointer to tracer_flags and make it point to the tracer it belongs to. When the option is setup, the set_flag of the right tracer will be used no matter what the the current_tracer is. And the old dummy_tracer_flags is used for all the tracers which doesn't have a tracer_flags, having issue to use it to save the pointer of a tracer. So remove it and use dynamic dummy tracer_flags for tracers needing a dummy tracer_flags, as a result, there are no tracers sharing tracer_flags, so remove the check code. And save the current tracer to trace_option_dentry seems not good as it may waste mem space when mount the debug/trace fs more than one time. Link: http://lkml.kernel.org/r/1457444222-8654-1-git-send-email-chuhu@redhat.com Signed-off-by: Chunyu Hu <chuhu@redhat.com> [ Fixed up function tracer options to work with the change ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-08 14:37:01 +01:00
struct tracer *trace = tracer_flags->trace;
int ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
if (ret)
return ret;
if (neg)
tracer_flags->val &= ~opts->bit;
else
tracer_flags->val |= opts->bit;
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
/* Try to assign a tracer specific option */
static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
{
struct tracer *trace = tr->current_trace;
struct tracer_flags *tracer_flags = trace->flags;
struct tracer_opt *opts = NULL;
int i;
for (i = 0; tracer_flags->opts[i].name; i++) {
opts = &tracer_flags->opts[i];
if (strcmp(cmp, opts->name) == 0)
return __set_tracer_option(tr, trace->flags, opts, neg);
}
return -EINVAL;
}
/* Some tracers require overwrite to stay enabled */
int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
{
if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
return -1;
return 0;
}
int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
{
/* do nothing if flag is already set */
if (!!(tr->trace_flags & mask) == !!enabled)
return 0;
/* Give the tracer a chance to approve the change */
if (tr->current_trace->flag_changed)
if (tr->current_trace->flag_changed(tr, mask, !!enabled))
return -EINVAL;
if (enabled)
tr->trace_flags |= mask;
else
tr->trace_flags &= ~mask;
if (mask == TRACE_ITER_RECORD_CMD)
trace_event_enable_cmd_record(enabled);
if (mask == TRACE_ITER_EVENT_FORK)
trace_event_follow_fork(tr, enabled);
if (mask == TRACE_ITER_OVERWRITE) {
ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
#ifdef CONFIG_TRACER_MAX_TRACE
ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
#endif
}
if (mask == TRACE_ITER_PRINTK) {
trace_printk_start_stop_comm(enabled);
trace_printk_control(enabled);
}
return 0;
}
static int trace_set_options(struct trace_array *tr, char *option)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
char *cmp;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int neg = 0;
int ret = -ENODEV;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int i;
size_t orig_len = strlen(option);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
cmp = strstrip(option);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (strncmp(cmp, "no", 2) == 0) {
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
neg = 1;
cmp += 2;
}
mutex_lock(&trace_types_lock);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
for (i = 0; trace_options[i]; i++) {
if (strcmp(cmp, trace_options[i]) == 0) {
ret = set_tracer_flag(tr, 1 << i, !neg);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
break;
}
}
/* If no option could be set, test the specific tracer options */
if (!trace_options[i])
ret = set_tracer_option(tr, cmp, neg);
mutex_unlock(&trace_types_lock);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
/*
* If the first trailing whitespace is replaced with '\0' by strstrip,
* turn it back into a space.
*/
if (orig_len > strlen(option))
option[strlen(option)] = ' ';
return ret;
}
static void __init apply_trace_boot_options(void)
{
char *buf = trace_boot_options_buf;
char *option;
while (true) {
option = strsep(&buf, ",");
if (!option)
break;
if (*option)
trace_set_options(&global_trace, option);
/* Put back the comma to allow this to be called again */
if (buf)
*(buf - 1) = ',';
}
}
static ssize_t
tracing_trace_options_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct seq_file *m = filp->private_data;
struct trace_array *tr = m->private;
char buf[64];
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = trace_set_options(tr, buf);
if (ret < 0)
return ret;
*ppos += cnt;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return cnt;
}
static int tracing_trace_options_open(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
int ret;
if (tracing_disabled)
return -ENODEV;
if (trace_array_get(tr) < 0)
return -ENODEV;
ret = single_open(file, tracing_trace_options_show, inode->i_private);
if (ret < 0)
trace_array_put(tr);
return ret;
}
static const struct file_operations tracing_iter_fops = {
.open = tracing_trace_options_open,
.read = seq_read,
.llseek = seq_lseek,
.release = tracing_single_release_tr,
.write = tracing_trace_options_write,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
static const char readme_msg[] =
"tracing mini-HOWTO:\n\n"
"# echo 0 > tracing_on : quick way to disable tracing\n"
"# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
" Important files:\n"
" trace\t\t\t- The static contents of the buffer\n"
"\t\t\t To clear the buffer write into this file: echo > trace\n"
" trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
" current_tracer\t- function and latency tracers\n"
" available_tracers\t- list of configured tracers for current_tracer\n"
" buffer_size_kb\t- view and modify size of per cpu buffer\n"
" buffer_total_size_kb - view total size of all cpu buffers\n\n"
" trace_clock\t\t-change the clock used to order events\n"
" local: Per cpu clock but may not be synced across CPUs\n"
" global: Synced across CPUs but slows tracing down.\n"
" counter: Not a clock, but just an increment\n"
" uptime: Jiffy counter from time of boot\n"
" perf: Same clock that perf events use\n"
#ifdef CONFIG_X86_64
" x86-tsc: TSC cycle counter\n"
#endif
"\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
" tracing_cpumask\t- Limit which CPUs to trace\n"
" instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
"\t\t\t Remove sub-buffer with rmdir\n"
" trace_options\t\t- Set format or modify how tracing happens\n"
"\t\t\t Disable an option by adding a suffix 'no' to the\n"
"\t\t\t option name\n"
" saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
#ifdef CONFIG_DYNAMIC_FTRACE
"\n available_filter_functions - list of functions that can be filtered on\n"
" set_ftrace_filter\t- echo function name in here to only trace these\n"
"\t\t\t functions\n"
"\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
"\t modules: Can select a group via module\n"
"\t Format: :mod:<module-name>\n"
"\t example: echo :mod:ext3 > set_ftrace_filter\n"
"\t triggers: a command to perform when function is hit\n"
"\t Format: <function>:<trigger>[:count]\n"
"\t trigger: traceon, traceoff\n"
"\t\t enable_event:<system>:<event>\n"
"\t\t disable_event:<system>:<event>\n"
#ifdef CONFIG_STACKTRACE
"\t\t stacktrace\n"
#endif
#ifdef CONFIG_TRACER_SNAPSHOT
"\t\t snapshot\n"
#endif
"\t\t dump\n"
"\t\t cpudump\n"
"\t example: echo do_fault:traceoff > set_ftrace_filter\n"
"\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
"\t The first one will disable tracing every time do_fault is hit\n"
"\t The second will disable tracing at most 3 times when do_trap is hit\n"
"\t The first time do trap is hit and it disables tracing, the\n"
"\t counter will decrement to 2. If tracing is already disabled,\n"
"\t the counter will not decrement. It only decrements when the\n"
"\t trigger did work\n"
"\t To remove trigger without count:\n"
"\t echo '!<function>:<trigger> > set_ftrace_filter\n"
"\t To remove trigger with a count:\n"
"\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
" set_ftrace_notrace\t- echo function name in here to never trace.\n"
"\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
"\t modules: Can select a group via module command :mod:\n"
"\t Does not accept triggers\n"
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_TRACER
" set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
"\t\t (function)\n"
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
" set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
" set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
" max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
#endif
#ifdef CONFIG_TRACER_SNAPSHOT
"\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
"\t\t\t snapshot buffer. Read the contents for more\n"
"\t\t\t information\n"
#endif
#ifdef CONFIG_STACK_TRACER
" stack_trace\t\t- Shows the max stack trace when active\n"
" stack_max_size\t- Shows current max stack size that was traced\n"
"\t\t\t Write into this file to reset the max size (trigger a\n"
"\t\t\t new trace)\n"
#ifdef CONFIG_DYNAMIC_FTRACE
" stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
"\t\t\t traces\n"
#endif
#endif /* CONFIG_STACK_TRACER */
#ifdef CONFIG_KPROBE_EVENT
" kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
"\t\t\t Write into this file to define/undefine new trace events.\n"
#endif
#ifdef CONFIG_UPROBE_EVENT
" uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
"\t\t\t Write into this file to define/undefine new trace events.\n"
#endif
#if defined(CONFIG_KPROBE_EVENT) || defined(CONFIG_UPROBE_EVENT)
"\t accepts: event-definitions (one definition per line)\n"
"\t Format: p|r[:[<group>/]<event>] <place> [<args>]\n"
"\t -:[<group>/]<event>\n"
#ifdef CONFIG_KPROBE_EVENT
"\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
#endif
#ifdef CONFIG_UPROBE_EVENT
"\t place: <path>:<offset>\n"
#endif
"\t args: <name>=fetcharg[:type]\n"
"\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
"\t $stack<index>, $stack, $retval, $comm\n"
"\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string,\n"
"\t b<bit-width>@<bit-offset>/<container-size>\n"
#endif
" events/\t\t- Directory containing all trace event subsystems:\n"
" enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
" events/<system>/\t- Directory containing all trace events for <system>:\n"
" enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
"\t\t\t events\n"
" filter\t\t- If set, only events passing filter are traced\n"
" events/<system>/<event>/\t- Directory containing control files for\n"
"\t\t\t <event>:\n"
" enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
" filter\t\t- If set, only events passing filter are traced\n"
" trigger\t\t- If set, a command to perform when event is hit\n"
"\t Format: <trigger>[:count][if <filter>]\n"
"\t trigger: traceon, traceoff\n"
"\t enable_event:<system>:<event>\n"
"\t disable_event:<system>:<event>\n"
#ifdef CONFIG_HIST_TRIGGERS
"\t enable_hist:<system>:<event>\n"
"\t disable_hist:<system>:<event>\n"
#endif
#ifdef CONFIG_STACKTRACE
"\t\t stacktrace\n"
#endif
#ifdef CONFIG_TRACER_SNAPSHOT
"\t\t snapshot\n"
tracing: Add 'hist' event trigger command 'hist' triggers allow users to continually aggregate trace events, which can then be viewed afterwards by simply reading a 'hist' file containing the aggregation in a human-readable format. The basic idea is very simple and boils down to a mechanism whereby trace events, rather than being exhaustively dumped in raw form and viewed directly, are automatically 'compressed' into meaningful tables completely defined by the user. This is done strictly via single-line command-line commands and without the aid of any kind of programming language or interpreter. A surprising number of typical use cases can be accomplished by users via this simple mechanism. In fact, a large number of the tasks that users typically do using the more complicated script-based tracing tools, at least during the initial stages of an investigation, can be accomplished by simply specifying a set of keys and values to be used in the creation of a hash table. The Linux kernel trace event subsystem happens to provide an extensive list of keys and values ready-made for such a purpose in the form of the event format files associated with each trace event. By simply consulting the format file for field names of interest and by plugging them into the hist trigger command, users can create an endless number of useful aggregations to help with investigating various properties of the system. See Documentation/trace/events.txt for examples. hist triggers are implemented on top of the existing event trigger infrastructure, and as such are consistent with the existing triggers from a user's perspective as well. The basic syntax follows the existing trigger syntax. Users start an aggregation by writing a 'hist' trigger to the event of interest's trigger file: # echo hist:keys=xxx [ if filter] > event/trigger Once a hist trigger has been set up, by default it continually aggregates every matching event into a hash table using the event key and a value field named 'hitcount'. To view the aggregation at any point in time, simply read the 'hist' file in the same directory as the 'trigger' file: # cat event/hist The detailed syntax provides additional options for user control, and is described exhaustively in Documentation/trace/events.txt and in the virtual tracing/README file in the tracing subsystem. Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-03 19:54:42 +01:00
#endif
#ifdef CONFIG_HIST_TRIGGERS
"\t\t hist (see below)\n"
#endif
"\t example: echo traceoff > events/block/block_unplug/trigger\n"
"\t echo traceoff:3 > events/block/block_unplug/trigger\n"
"\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
"\t events/block/block_unplug/trigger\n"
"\t The first disables tracing every time block_unplug is hit.\n"
"\t The second disables tracing the first 3 times block_unplug is hit.\n"
"\t The third enables the kmalloc event the first 3 times block_unplug\n"
"\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
"\t Like function triggers, the counter is only decremented if it\n"
"\t enabled or disabled tracing.\n"
"\t To remove a trigger without a count:\n"
"\t echo '!<trigger> > <system>/<event>/trigger\n"
"\t To remove a trigger with a count:\n"
"\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
"\t Filters can be ignored when removing a trigger.\n"
tracing: Add 'hist' event trigger command 'hist' triggers allow users to continually aggregate trace events, which can then be viewed afterwards by simply reading a 'hist' file containing the aggregation in a human-readable format. The basic idea is very simple and boils down to a mechanism whereby trace events, rather than being exhaustively dumped in raw form and viewed directly, are automatically 'compressed' into meaningful tables completely defined by the user. This is done strictly via single-line command-line commands and without the aid of any kind of programming language or interpreter. A surprising number of typical use cases can be accomplished by users via this simple mechanism. In fact, a large number of the tasks that users typically do using the more complicated script-based tracing tools, at least during the initial stages of an investigation, can be accomplished by simply specifying a set of keys and values to be used in the creation of a hash table. The Linux kernel trace event subsystem happens to provide an extensive list of keys and values ready-made for such a purpose in the form of the event format files associated with each trace event. By simply consulting the format file for field names of interest and by plugging them into the hist trigger command, users can create an endless number of useful aggregations to help with investigating various properties of the system. See Documentation/trace/events.txt for examples. hist triggers are implemented on top of the existing event trigger infrastructure, and as such are consistent with the existing triggers from a user's perspective as well. The basic syntax follows the existing trigger syntax. Users start an aggregation by writing a 'hist' trigger to the event of interest's trigger file: # echo hist:keys=xxx [ if filter] > event/trigger Once a hist trigger has been set up, by default it continually aggregates every matching event into a hash table using the event key and a value field named 'hitcount'. To view the aggregation at any point in time, simply read the 'hist' file in the same directory as the 'trigger' file: # cat event/hist The detailed syntax provides additional options for user control, and is described exhaustively in Documentation/trace/events.txt and in the virtual tracing/README file in the tracing subsystem. Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-03 19:54:42 +01:00
#ifdef CONFIG_HIST_TRIGGERS
" hist trigger\t- If set, event hits are aggregated into a hash table\n"
"\t Format: hist:keys=<field1[,field2,...]>\n"
"\t [:values=<field1[,field2,...]>]\n"
"\t [:sort=<field1[,field2,...]>]\n"
tracing: Add 'hist' event trigger command 'hist' triggers allow users to continually aggregate trace events, which can then be viewed afterwards by simply reading a 'hist' file containing the aggregation in a human-readable format. The basic idea is very simple and boils down to a mechanism whereby trace events, rather than being exhaustively dumped in raw form and viewed directly, are automatically 'compressed' into meaningful tables completely defined by the user. This is done strictly via single-line command-line commands and without the aid of any kind of programming language or interpreter. A surprising number of typical use cases can be accomplished by users via this simple mechanism. In fact, a large number of the tasks that users typically do using the more complicated script-based tracing tools, at least during the initial stages of an investigation, can be accomplished by simply specifying a set of keys and values to be used in the creation of a hash table. The Linux kernel trace event subsystem happens to provide an extensive list of keys and values ready-made for such a purpose in the form of the event format files associated with each trace event. By simply consulting the format file for field names of interest and by plugging them into the hist trigger command, users can create an endless number of useful aggregations to help with investigating various properties of the system. See Documentation/trace/events.txt for examples. hist triggers are implemented on top of the existing event trigger infrastructure, and as such are consistent with the existing triggers from a user's perspective as well. The basic syntax follows the existing trigger syntax. Users start an aggregation by writing a 'hist' trigger to the event of interest's trigger file: # echo hist:keys=xxx [ if filter] > event/trigger Once a hist trigger has been set up, by default it continually aggregates every matching event into a hash table using the event key and a value field named 'hitcount'. To view the aggregation at any point in time, simply read the 'hist' file in the same directory as the 'trigger' file: # cat event/hist The detailed syntax provides additional options for user control, and is described exhaustively in Documentation/trace/events.txt and in the virtual tracing/README file in the tracing subsystem. Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-03 19:54:42 +01:00
"\t [:size=#entries]\n"
"\t [:pause][:continue][:clear]\n"
"\t [:name=histname1]\n"
tracing: Add 'hist' event trigger command 'hist' triggers allow users to continually aggregate trace events, which can then be viewed afterwards by simply reading a 'hist' file containing the aggregation in a human-readable format. The basic idea is very simple and boils down to a mechanism whereby trace events, rather than being exhaustively dumped in raw form and viewed directly, are automatically 'compressed' into meaningful tables completely defined by the user. This is done strictly via single-line command-line commands and without the aid of any kind of programming language or interpreter. A surprising number of typical use cases can be accomplished by users via this simple mechanism. In fact, a large number of the tasks that users typically do using the more complicated script-based tracing tools, at least during the initial stages of an investigation, can be accomplished by simply specifying a set of keys and values to be used in the creation of a hash table. The Linux kernel trace event subsystem happens to provide an extensive list of keys and values ready-made for such a purpose in the form of the event format files associated with each trace event. By simply consulting the format file for field names of interest and by plugging them into the hist trigger command, users can create an endless number of useful aggregations to help with investigating various properties of the system. See Documentation/trace/events.txt for examples. hist triggers are implemented on top of the existing event trigger infrastructure, and as such are consistent with the existing triggers from a user's perspective as well. The basic syntax follows the existing trigger syntax. Users start an aggregation by writing a 'hist' trigger to the event of interest's trigger file: # echo hist:keys=xxx [ if filter] > event/trigger Once a hist trigger has been set up, by default it continually aggregates every matching event into a hash table using the event key and a value field named 'hitcount'. To view the aggregation at any point in time, simply read the 'hist' file in the same directory as the 'trigger' file: # cat event/hist The detailed syntax provides additional options for user control, and is described exhaustively in Documentation/trace/events.txt and in the virtual tracing/README file in the tracing subsystem. Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-03 19:54:42 +01:00
"\t [if <filter>]\n\n"
"\t When a matching event is hit, an entry is added to a hash\n"
"\t table using the key(s) and value(s) named, and the value of a\n"
"\t sum called 'hitcount' is incremented. Keys and values\n"
"\t correspond to fields in the event's format description. Keys\n"
"\t can be any field, or the special string 'stacktrace'.\n"
"\t Compound keys consisting of up to two fields can be specified\n"
"\t by the 'keys' keyword. Values must correspond to numeric\n"
"\t fields. Sort keys consisting of up to two fields can be\n"
"\t specified using the 'sort' keyword. The sort direction can\n"
"\t be modified by appending '.descending' or '.ascending' to a\n"
"\t sort field. The 'size' parameter can be used to specify more\n"
"\t or fewer than the default 2048 entries for the hashtable size.\n"
"\t If a hist trigger is given a name using the 'name' parameter,\n"
"\t its histogram data will be shared with other triggers of the\n"
"\t same name, and trigger hits will update this common data.\n\n"
tracing: Add 'hist' event trigger command 'hist' triggers allow users to continually aggregate trace events, which can then be viewed afterwards by simply reading a 'hist' file containing the aggregation in a human-readable format. The basic idea is very simple and boils down to a mechanism whereby trace events, rather than being exhaustively dumped in raw form and viewed directly, are automatically 'compressed' into meaningful tables completely defined by the user. This is done strictly via single-line command-line commands and without the aid of any kind of programming language or interpreter. A surprising number of typical use cases can be accomplished by users via this simple mechanism. In fact, a large number of the tasks that users typically do using the more complicated script-based tracing tools, at least during the initial stages of an investigation, can be accomplished by simply specifying a set of keys and values to be used in the creation of a hash table. The Linux kernel trace event subsystem happens to provide an extensive list of keys and values ready-made for such a purpose in the form of the event format files associated with each trace event. By simply consulting the format file for field names of interest and by plugging them into the hist trigger command, users can create an endless number of useful aggregations to help with investigating various properties of the system. See Documentation/trace/events.txt for examples. hist triggers are implemented on top of the existing event trigger infrastructure, and as such are consistent with the existing triggers from a user's perspective as well. The basic syntax follows the existing trigger syntax. Users start an aggregation by writing a 'hist' trigger to the event of interest's trigger file: # echo hist:keys=xxx [ if filter] > event/trigger Once a hist trigger has been set up, by default it continually aggregates every matching event into a hash table using the event key and a value field named 'hitcount'. To view the aggregation at any point in time, simply read the 'hist' file in the same directory as the 'trigger' file: # cat event/hist The detailed syntax provides additional options for user control, and is described exhaustively in Documentation/trace/events.txt and in the virtual tracing/README file in the tracing subsystem. Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-03 19:54:42 +01:00
"\t Reading the 'hist' file for the event will dump the hash\n"
"\t table in its entirety to stdout. If there are multiple hist\n"
"\t triggers attached to an event, there will be a table for each\n"
"\t trigger in the output. The table displayed for a named\n"
"\t trigger will be the same as any other instance having the\n"
"\t same name. The default format used to display a given field\n"
"\t can be modified by appending any of the following modifiers\n"
"\t to the field name, as applicable:\n\n"
"\t .hex display a number as a hex value\n"
"\t .sym display an address as a symbol\n"
"\t .sym-offset display an address as a symbol and offset\n"
"\t .execname display a common_pid as a program name\n"
"\t .syscall display a syscall id as a syscall name\n\n"
tracing: Add hist trigger 'log2' modifier Allow users to have numeric fields displayed as log2 values in case value range is very wide by appending '.log2' to field names. For example, # echo 'hist:key=bytes_req' > kmalloc/trigger # cat kmalloc/hist { bytes_req: 504 } hitcount: 1 { bytes_req: 11 } hitcount: 1 { bytes_req: 104 } hitcount: 1 { bytes_req: 48 } hitcount: 1 { bytes_req: 2048 } hitcount: 1 { bytes_req: 4096 } hitcount: 1 { bytes_req: 240 } hitcount: 1 { bytes_req: 392 } hitcount: 1 { bytes_req: 13 } hitcount: 1 { bytes_req: 28 } hitcount: 1 { bytes_req: 12 } hitcount: 1 { bytes_req: 64 } hitcount: 2 { bytes_req: 128 } hitcount: 2 { bytes_req: 32 } hitcount: 2 { bytes_req: 8 } hitcount: 11 { bytes_req: 10 } hitcount: 13 { bytes_req: 24 } hitcount: 25 { bytes_req: 160 } hitcount: 29 { bytes_req: 16 } hitcount: 33 { bytes_req: 80 } hitcount: 36 When using '.log2' modifier, the output looks like: # echo 'hist:key=bytes_req.log2' > kmalloc/trigger # cat kmalloc/hist { bytes_req: ~ 2^12 } hitcount: 1 { bytes_req: ~ 2^11 } hitcount: 1 { bytes_req: ~ 2^9 } hitcount: 2 { bytes_req: ~ 2^6 } hitcount: 3 { bytes_req: ~ 2^3 } hitcount: 13 { bytes_req: ~ 2^5 } hitcount: 19 { bytes_req: ~ 2^8 } hitcount: 49 { bytes_req: ~ 2^7 } hitcount: 57 { bytes_req: ~ 2^4 } hitcount: 74 Link: http://lkml.kernel.org/r/7ff396b246c6a881f46b979735fddf05a0d6c71a.1457029949.git.tom.zanussi@linux.intel.com Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-03 19:55:02 +01:00
"\t .log2 display log2 value rather than raw number\n\n"
"\t The 'pause' parameter can be used to pause an existing hist\n"
"\t trigger or to start a hist trigger but not log any events\n"
"\t until told to do so. 'continue' can be used to start or\n"
"\t restart a paused hist trigger.\n\n"
"\t The 'clear' parameter will clear the contents of a running\n"
"\t hist trigger and leave its current paused/active state\n"
"\t unchanged.\n\n"
"\t The enable_hist and disable_hist triggers can be used to\n"
"\t have one event conditionally start and stop another event's\n"
"\t already-attached hist trigger. The syntax is analagous to\n"
"\t the enable_event and disable_event triggers.\n"
tracing: Add 'hist' event trigger command 'hist' triggers allow users to continually aggregate trace events, which can then be viewed afterwards by simply reading a 'hist' file containing the aggregation in a human-readable format. The basic idea is very simple and boils down to a mechanism whereby trace events, rather than being exhaustively dumped in raw form and viewed directly, are automatically 'compressed' into meaningful tables completely defined by the user. This is done strictly via single-line command-line commands and without the aid of any kind of programming language or interpreter. A surprising number of typical use cases can be accomplished by users via this simple mechanism. In fact, a large number of the tasks that users typically do using the more complicated script-based tracing tools, at least during the initial stages of an investigation, can be accomplished by simply specifying a set of keys and values to be used in the creation of a hash table. The Linux kernel trace event subsystem happens to provide an extensive list of keys and values ready-made for such a purpose in the form of the event format files associated with each trace event. By simply consulting the format file for field names of interest and by plugging them into the hist trigger command, users can create an endless number of useful aggregations to help with investigating various properties of the system. See Documentation/trace/events.txt for examples. hist triggers are implemented on top of the existing event trigger infrastructure, and as such are consistent with the existing triggers from a user's perspective as well. The basic syntax follows the existing trigger syntax. Users start an aggregation by writing a 'hist' trigger to the event of interest's trigger file: # echo hist:keys=xxx [ if filter] > event/trigger Once a hist trigger has been set up, by default it continually aggregates every matching event into a hash table using the event key and a value field named 'hitcount'. To view the aggregation at any point in time, simply read the 'hist' file in the same directory as the 'trigger' file: # cat event/hist The detailed syntax provides additional options for user control, and is described exhaustively in Documentation/trace/events.txt and in the virtual tracing/README file in the tracing subsystem. Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-03 19:54:42 +01:00
#endif
;
static ssize_t
tracing_readme_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return simple_read_from_buffer(ubuf, cnt, ppos,
readme_msg, strlen(readme_msg));
}
static const struct file_operations tracing_readme_fops = {
.open = tracing_open_generic,
.read = tracing_readme_read,
.llseek = generic_file_llseek,
};
static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
{
unsigned int *ptr = v;
if (*pos || m->count)
ptr++;
(*pos)++;
for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
ptr++) {
if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
continue;
return ptr;
}
return NULL;
}
static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
{
void *v;
loff_t l = 0;
preempt_disable();
arch_spin_lock(&trace_cmdline_lock);
v = &savedcmd->map_cmdline_to_pid[0];
while (l <= *pos) {
v = saved_cmdlines_next(m, v, &l);
if (!v)
return NULL;
}
return v;
}
static void saved_cmdlines_stop(struct seq_file *m, void *v)
{
arch_spin_unlock(&trace_cmdline_lock);
preempt_enable();
}
static int saved_cmdlines_show(struct seq_file *m, void *v)
{
char buf[TASK_COMM_LEN];
unsigned int *pid = v;
__trace_find_cmdline(*pid, buf);
seq_printf(m, "%d %s\n", *pid, buf);
return 0;
}
static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
.start = saved_cmdlines_start,
.next = saved_cmdlines_next,
.stop = saved_cmdlines_stop,
.show = saved_cmdlines_show,
};
static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
{
if (tracing_disabled)
return -ENODEV;
return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
}
static const struct file_operations tracing_saved_cmdlines_fops = {
.open = tracing_saved_cmdlines_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static ssize_t
tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64];
int r;
arch_spin_lock(&trace_cmdline_lock);
r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
arch_spin_unlock(&trace_cmdline_lock);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
{
kfree(s->saved_cmdlines);
kfree(s->map_cmdline_to_pid);
kfree(s);
}
static int tracing_resize_saved_cmdlines(unsigned int val)
{
struct saved_cmdlines_buffer *s, *savedcmd_temp;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
if (allocate_cmdlines_buffer(val, s) < 0) {
kfree(s);
return -ENOMEM;
}
arch_spin_lock(&trace_cmdline_lock);
savedcmd_temp = savedcmd;
savedcmd = s;
arch_spin_unlock(&trace_cmdline_lock);
free_saved_cmdlines_buffer(savedcmd_temp);
return 0;
}
static ssize_t
tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
unsigned long val;
int ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
/* must have at least 1 entry or less than PID_MAX_DEFAULT */
if (!val || val > PID_MAX_DEFAULT)
return -EINVAL;
ret = tracing_resize_saved_cmdlines((unsigned int)val);
if (ret < 0)
return ret;
*ppos += cnt;
return cnt;
}
static const struct file_operations tracing_saved_cmdlines_size_fops = {
.open = tracing_open_generic,
.read = tracing_saved_cmdlines_size_read,
.write = tracing_saved_cmdlines_size_write,
};
#ifdef CONFIG_TRACE_ENUM_MAP_FILE
static union trace_enum_map_item *
update_enum_map(union trace_enum_map_item *ptr)
{
if (!ptr->map.enum_string) {
if (ptr->tail.next) {
ptr = ptr->tail.next;
/* Set ptr to the next real item (skip head) */
ptr++;
} else
return NULL;
}
return ptr;
}
static void *enum_map_next(struct seq_file *m, void *v, loff_t *pos)
{
union trace_enum_map_item *ptr = v;
/*
* Paranoid! If ptr points to end, we don't want to increment past it.
* This really should never happen.
*/
ptr = update_enum_map(ptr);
if (WARN_ON_ONCE(!ptr))
return NULL;
ptr++;
(*pos)++;
ptr = update_enum_map(ptr);
return ptr;
}
static void *enum_map_start(struct seq_file *m, loff_t *pos)
{
union trace_enum_map_item *v;
loff_t l = 0;
mutex_lock(&trace_enum_mutex);
v = trace_enum_maps;
if (v)
v++;
while (v && l < *pos) {
v = enum_map_next(m, v, &l);
}
return v;
}
static void enum_map_stop(struct seq_file *m, void *v)
{
mutex_unlock(&trace_enum_mutex);
}
static int enum_map_show(struct seq_file *m, void *v)
{
union trace_enum_map_item *ptr = v;
seq_printf(m, "%s %ld (%s)\n",
ptr->map.enum_string, ptr->map.enum_value,
ptr->map.system);
return 0;
}
static const struct seq_operations tracing_enum_map_seq_ops = {
.start = enum_map_start,
.next = enum_map_next,
.stop = enum_map_stop,
.show = enum_map_show,
};
static int tracing_enum_map_open(struct inode *inode, struct file *filp)
{
if (tracing_disabled)
return -ENODEV;
return seq_open(filp, &tracing_enum_map_seq_ops);
}
static const struct file_operations tracing_enum_map_fops = {
.open = tracing_enum_map_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static inline union trace_enum_map_item *
trace_enum_jmp_to_tail(union trace_enum_map_item *ptr)
{
/* Return tail of array given the head */
return ptr + ptr->head.length + 1;
}
static void
trace_insert_enum_map_file(struct module *mod, struct trace_enum_map **start,
int len)
{
struct trace_enum_map **stop;
struct trace_enum_map **map;
union trace_enum_map_item *map_array;
union trace_enum_map_item *ptr;
stop = start + len;
/*
* The trace_enum_maps contains the map plus a head and tail item,
* where the head holds the module and length of array, and the
* tail holds a pointer to the next list.
*/
map_array = kmalloc(sizeof(*map_array) * (len + 2), GFP_KERNEL);
if (!map_array) {
pr_warn("Unable to allocate trace enum mapping\n");
return;
}
mutex_lock(&trace_enum_mutex);
if (!trace_enum_maps)
trace_enum_maps = map_array;
else {
ptr = trace_enum_maps;
for (;;) {
ptr = trace_enum_jmp_to_tail(ptr);
if (!ptr->tail.next)
break;
ptr = ptr->tail.next;
}
ptr->tail.next = map_array;
}
map_array->head.mod = mod;
map_array->head.length = len;
map_array++;
for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
map_array->map = **map;
map_array++;
}
memset(map_array, 0, sizeof(*map_array));
mutex_unlock(&trace_enum_mutex);
}
static void trace_create_enum_file(struct dentry *d_tracer)
{
trace_create_file("enum_map", 0444, d_tracer,
NULL, &tracing_enum_map_fops);
}
#else /* CONFIG_TRACE_ENUM_MAP_FILE */
static inline void trace_create_enum_file(struct dentry *d_tracer) { }
static inline void trace_insert_enum_map_file(struct module *mod,
struct trace_enum_map **start, int len) { }
#endif /* !CONFIG_TRACE_ENUM_MAP_FILE */
static void trace_insert_enum_map(struct module *mod,
struct trace_enum_map **start, int len)
tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values Several tracepoints use the helper functions __print_symbolic() or __print_flags() and pass in enums that do the mapping between the binary data stored and the value to print. This works well for reading the ASCII trace files, but when the data is read via userspace tools such as perf and trace-cmd, the conversion of the binary value to a human string format is lost if an enum is used, as userspace does not have access to what the ENUM is. For example, the tracepoint trace_tlb_flush() has: __print_symbolic(REC->reason, { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }) Which maps the enum values to the strings they represent. But perf and trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would not be able to map it. With TRACE_DEFINE_ENUM(), developers can place these in the event header files and ftrace will convert the enums to their values: By adding: TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH); TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN); $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format [...] __print_symbolic(REC->reason, { 0, "flush on task switch" }, { 1, "remote shootdown" }, { 2, "local shootdown" }, { 3, "local mm shootdown" }) The above is what userspace expects to see, and tools do not need to be modified to parse them. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Cc: Guilherme Cox <cox@computer.org> Cc: Tony Luck <tony.luck@gmail.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-03-24 22:58:09 +01:00
{
struct trace_enum_map **map;
if (len <= 0)
return;
map = start;
trace_event_enum_update(map, len);
trace_insert_enum_map_file(mod, start, len);
tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values Several tracepoints use the helper functions __print_symbolic() or __print_flags() and pass in enums that do the mapping between the binary data stored and the value to print. This works well for reading the ASCII trace files, but when the data is read via userspace tools such as perf and trace-cmd, the conversion of the binary value to a human string format is lost if an enum is used, as userspace does not have access to what the ENUM is. For example, the tracepoint trace_tlb_flush() has: __print_symbolic(REC->reason, { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }) Which maps the enum values to the strings they represent. But perf and trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would not be able to map it. With TRACE_DEFINE_ENUM(), developers can place these in the event header files and ftrace will convert the enums to their values: By adding: TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH); TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN); $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format [...] __print_symbolic(REC->reason, { 0, "flush on task switch" }, { 1, "remote shootdown" }, { 2, "local shootdown" }, { 3, "local mm shootdown" }) The above is what userspace expects to see, and tools do not need to be modified to parse them. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Cc: Guilherme Cox <cox@computer.org> Cc: Tony Luck <tony.luck@gmail.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-03-24 22:58:09 +01:00
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static ssize_t
tracing_set_trace_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_array *tr = filp->private_data;
char buf[MAX_TRACER_SIZE+2];
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int r;
mutex_lock(&trace_types_lock);
r = sprintf(buf, "%s\n", tr->current_trace->name);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_unlock(&trace_types_lock);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
int tracer_init(struct tracer *t, struct trace_array *tr)
{
tracing_reset_online_cpus(&tr->trace_buffer);
return t->init(tr);
}
static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
{
int cpu;
for_each_tracing_cpu(cpu)
per_cpu_ptr(buf->data, cpu)->entries = val;
}
#ifdef CONFIG_TRACER_MAX_TRACE
/* resize @tr's buffer to the size of @size_tr's entries */
static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
struct trace_buffer *size_buf, int cpu_id)
{
int cpu, ret = 0;
if (cpu_id == RING_BUFFER_ALL_CPUS) {
for_each_tracing_cpu(cpu) {
ret = ring_buffer_resize(trace_buf->buffer,
per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
if (ret < 0)
break;
per_cpu_ptr(trace_buf->data, cpu)->entries =
per_cpu_ptr(size_buf->data, cpu)->entries;
}
} else {
ret = ring_buffer_resize(trace_buf->buffer,
per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
if (ret == 0)
per_cpu_ptr(trace_buf->data, cpu_id)->entries =
per_cpu_ptr(size_buf->data, cpu_id)->entries;
}
return ret;
}
#endif /* CONFIG_TRACER_MAX_TRACE */
static int __tracing_resize_ring_buffer(struct trace_array *tr,
unsigned long size, int cpu)
{
int ret;
/*
* If kernel or user changes the size of the ring buffer
* we use the size that was given, and we can forget about
* expanding it later.
*/
ring_buffer_expanded = true;
/* May be called before buffers are initialized */
if (!tr->trace_buffer.buffer)
return 0;
ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
if (ret < 0)
return ret;
#ifdef CONFIG_TRACER_MAX_TRACE
if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
!tr->current_trace->use_max_tr)
tracing: Shrink max latency ringbuffer if unnecessary Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-01 07:34:35 +02:00
goto out;
ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
if (ret < 0) {
int r = resize_buffer_duplicate_size(&tr->trace_buffer,
&tr->trace_buffer, cpu);
if (r < 0) {
/*
* AARGH! We are left with different
* size max buffer!!!!
* The max buffer is our "snapshot" buffer.
* When a tracer needs a snapshot (one of the
* latency tracers), it swaps the max buffer
* with the saved snap shot. We succeeded to
* update the size of the main buffer, but failed to
* update the size of the max buffer. But when we tried
* to reset the main buffer to the original size, we
* failed there too. This is very unlikely to
* happen, but if it does, warn and kill all
* tracing.
*/
WARN_ON(1);
tracing_disabled = 1;
}
return ret;
}
if (cpu == RING_BUFFER_ALL_CPUS)
set_buffer_entries(&tr->max_buffer, size);
else
per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
tracing: Shrink max latency ringbuffer if unnecessary Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-01 07:34:35 +02:00
out:
#endif /* CONFIG_TRACER_MAX_TRACE */
if (cpu == RING_BUFFER_ALL_CPUS)
set_buffer_entries(&tr->trace_buffer, size);
else
per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
return ret;
}
static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
unsigned long size, int cpu_id)
{
int ret = size;
mutex_lock(&trace_types_lock);
if (cpu_id != RING_BUFFER_ALL_CPUS) {
/* make sure, this cpu is enabled in the mask */
if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
ret = -EINVAL;
goto out;
}
}
ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
if (ret < 0)
ret = -ENOMEM;
out:
mutex_unlock(&trace_types_lock);
return ret;
}
tracing: Shrink max latency ringbuffer if unnecessary Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-01 07:34:35 +02:00
/**
* tracing_update_buffers - used by tracing facility to expand ring buffers
*
* To save on memory when the tracing is never used on a system with it
* configured in. The ring buffers are set to a minimum size. But once
* a user starts to use the tracing facility, then they need to grow
* to their default size.
*
* This function is to be called when a tracer is about to be used.
*/
int tracing_update_buffers(void)
{
int ret = 0;
mutex_lock(&trace_types_lock);
if (!ring_buffer_expanded)
ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
RING_BUFFER_ALL_CPUS);
mutex_unlock(&trace_types_lock);
return ret;
}
struct trace_option_dentry;
static void
create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
/*
* Used to clear out the tracer before deletion of an instance.
* Must have trace_types_lock held.
*/
static void tracing_set_nop(struct trace_array *tr)
{
if (tr->current_trace == &nop_trace)
return;
tr->current_trace->enabled--;
if (tr->current_trace->reset)
tr->current_trace->reset(tr);
tr->current_trace = &nop_trace;
}
static void add_tracer_options(struct trace_array *tr, struct tracer *t)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
/* Only enable if the directory has been created already. */
if (!tr->dir)
return;
create_trace_option_files(tr, t);
}
static int tracing_set_tracer(struct trace_array *tr, const char *buf)
{
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
struct tracer *t;
#ifdef CONFIG_TRACER_MAX_TRACE
bool had_max_tr;
#endif
int ret = 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
mutex_lock(&trace_types_lock);
if (!ring_buffer_expanded) {
ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
RING_BUFFER_ALL_CPUS);
if (ret < 0)
goto out;
ret = 0;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
for (t = trace_types; t; t = t->next) {
if (strcmp(t->name, buf) == 0)
break;
}
if (!t) {
ret = -EINVAL;
goto out;
}
if (t == tr->current_trace)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
goto out;
/* Some tracers are only allowed for the top level buffer */
if (!trace_ok_for_array(t, tr)) {
ret = -EINVAL;
goto out;
}
/* If trace pipe files are being read, we can't change the tracer */
if (tr->current_trace->ref) {
ret = -EBUSY;
goto out;
}
trace_branch_disable();
tr->current_trace->enabled--;
if (tr->current_trace->reset)
tr->current_trace->reset(tr);
/* Current trace needs to be nop_trace before synchronize_sched */
tr->current_trace = &nop_trace;
#ifdef CONFIG_TRACER_MAX_TRACE
had_max_tr = tr->allocated_snapshot;
if (had_max_tr && !t->use_max_tr) {
/*
* We need to make sure that the update_max_tr sees that
* current_trace changed to nop_trace to keep it from
* swapping the buffers after we resize it.
* The update_max_tr is called from interrupts disabled
* so a synchronized_sched() is sufficient.
*/
synchronize_sched();
free_snapshot(tr);
tracing: Shrink max latency ringbuffer if unnecessary Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-01 07:34:35 +02:00
}
#endif
#ifdef CONFIG_TRACER_MAX_TRACE
if (t->use_max_tr && !had_max_tr) {
ret = alloc_snapshot(tr);
if (ret < 0)
goto out;
tracing: Shrink max latency ringbuffer if unnecessary Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-07-01 07:34:35 +02:00
}
#endif
if (t->init) {
ret = tracer_init(t, tr);
if (ret)
goto out;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
tr->current_trace = t;
tr->current_trace->enabled++;
trace_branch_enable(tr);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
out:
mutex_unlock(&trace_types_lock);
return ret;
}
static ssize_t
tracing_set_trace_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_array *tr = filp->private_data;
char buf[MAX_TRACER_SIZE+1];
int i;
size_t ret;
int err;
ret = cnt;
if (cnt > MAX_TRACER_SIZE)
cnt = MAX_TRACER_SIZE;
if (copy_from_user(buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
/* strip ending whitespace. */
for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
buf[i] = 0;
err = tracing_set_tracer(tr, buf);
if (err)
return err;
*ppos += ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
return ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static ssize_t
tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
size_t cnt, loff_t *ppos)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
char buf[64];
int r;
r = snprintf(buf, sizeof(buf), "%ld\n",
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
*ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
if (r > sizeof(buf))
r = sizeof(buf);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static ssize_t
tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
size_t cnt, loff_t *ppos)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
unsigned long val;
int ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
*ptr = val * 1000;
return cnt;
}
static ssize_t
tracing_thresh_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
}
static ssize_t
tracing_thresh_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_array *tr = filp->private_data;
int ret;
mutex_lock(&trace_types_lock);
ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
if (ret < 0)
goto out;
if (tr->current_trace->update_thresh) {
ret = tr->current_trace->update_thresh(tr);
if (ret < 0)
goto out;
}
ret = cnt;
out:
mutex_unlock(&trace_types_lock);
return ret;
}
#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
static ssize_t
tracing_max_lat_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
}
static ssize_t
tracing_max_lat_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
}
#endif
static int tracing_open_pipe(struct inode *inode, struct file *filp)
{
struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
int ret = 0;
if (tracing_disabled)
return -ENODEV;
if (trace_array_get(tr) < 0)
return -ENODEV;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
mutex_lock(&trace_types_lock);
/* create a buffer to store the information to pass to userspace */
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
if (!iter) {
ret = -ENOMEM;
__trace_array_put(tr);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
goto out;
}
trace_seq_init(&iter->seq);
iter->trace = tr->current_trace;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
ret = -ENOMEM;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
goto fail;
}
/* trace pipe does not show start of buffer */
cpumask_setall(iter->started);
if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
iter->iter_flags |= TRACE_FILE_LAT_FMT;
tracing: Format non-nanosec times from tsc clock without a decimal point. With the addition of the "tsc" clock, formatting timestamps to look like fractional seconds is misleading. Mark clocks as either in nanoseconds or not, and format non-nanosecond timestamps as decimal integers. Tested: $ cd /sys/kernel/debug/tracing/ $ cat trace_clock [local] global tsc $ echo sched_switch > set_event $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ cat trace <idle>-0 [000] 6330.555552: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 [000] 6330.555628: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo 1 > options/latency-format $ cat trace <idle>-0 0 4104553247us+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 0 4104553322us+: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo tsc > trace_clock $ cat trace $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ echo 0 > options/latency-format $ cat trace <idle>-0 [000] 16490053398357: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 [000] 16490053588518: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... echo 1 > options/latency-format $ cat trace <idle>-0 0 91557653238+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 0 91557843399+: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... v2: Move arch-specific bits out of generic code. v4: Fix x86_32 build due to 64-bit division. Google-Bug-Id: 6980623 Link: http://lkml.kernel.org/r/1352837903-32191-2-git-send-email-dhsharp@google.com Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: David Sharp <dhsharp@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-13 21:18:22 +01:00
/* Output in nanoseconds only if we are using a clock in nanoseconds. */
if (trace_clocks[tr->clock_id].in_ns)
tracing: Format non-nanosec times from tsc clock without a decimal point. With the addition of the "tsc" clock, formatting timestamps to look like fractional seconds is misleading. Mark clocks as either in nanoseconds or not, and format non-nanosecond timestamps as decimal integers. Tested: $ cd /sys/kernel/debug/tracing/ $ cat trace_clock [local] global tsc $ echo sched_switch > set_event $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ cat trace <idle>-0 [000] 6330.555552: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 [000] 6330.555628: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo 1 > options/latency-format $ cat trace <idle>-0 0 4104553247us+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120 sleep-29964 0 4104553322us+: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... $ echo tsc > trace_clock $ cat trace $ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on $ echo 0 > options/latency-format $ cat trace <idle>-0 [000] 16490053398357: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 [000] 16490053588518: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... echo 1 > options/latency-format $ cat trace <idle>-0 0 91557653238+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120 sleep-31128 0 91557843399+: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120 ... v2: Move arch-specific bits out of generic code. v4: Fix x86_32 build due to 64-bit division. Google-Bug-Id: 6980623 Link: http://lkml.kernel.org/r/1352837903-32191-2-git-send-email-dhsharp@google.com Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: David Sharp <dhsharp@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-13 21:18:22 +01:00
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
iter->tr = tr;
iter->trace_buffer = &tr->trace_buffer;
iter->cpu_file = tracing_get_cpu(inode);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_init(&iter->mutex);
filp->private_data = iter;
if (iter->trace->pipe_open)
iter->trace->pipe_open(iter);
nonseekable_open(inode, filp);
tr->current_trace->ref++;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
out:
mutex_unlock(&trace_types_lock);
return ret;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
fail:
kfree(iter->trace);
kfree(iter);
__trace_array_put(tr);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_unlock(&trace_types_lock);
return ret;
}
static int tracing_release_pipe(struct inode *inode, struct file *file)
{
struct trace_iterator *iter = file->private_data;
struct trace_array *tr = inode->i_private;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
mutex_lock(&trace_types_lock);
tr->current_trace->ref--;
if (iter->trace->pipe_close)
iter->trace->pipe_close(iter);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
mutex_unlock(&trace_types_lock);
free_cpumask_var(iter->started);
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_destroy(&iter->mutex);
kfree(iter);
trace_array_put(tr);
return 0;
}
static unsigned int
trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
{
struct trace_array *tr = iter->tr;
/* Iterators are static, they should be filled or empty */
if (trace_buffer_iter(iter, iter->cpu_file))
return POLLIN | POLLRDNORM;
if (tr->trace_flags & TRACE_ITER_BLOCK)
/*
* Always select as readable when in blocking mode
*/
return POLLIN | POLLRDNORM;
else
return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
filp, poll_table);
}
static unsigned int
tracing_poll_pipe(struct file *filp, poll_table *poll_table)
{
struct trace_iterator *iter = filp->private_data;
return trace_poll(iter, filp, poll_table);
}
/* Must be called with iter->mutex held. */
static int tracing_wait_pipe(struct file *filp)
{
struct trace_iterator *iter = filp->private_data;
int ret;
while (trace_empty(iter)) {
if ((filp->f_flags & O_NONBLOCK)) {
return -EAGAIN;
}
/*
* We block until we read something and tracing is disabled.
* We still block if tracing is disabled, but we have never
* read anything. This allows a user to cat this file, and
* then enable tracing. But after we have read something,
* we give an EOF when tracing is again disabled.
*
* iter->pos will be 0 if we haven't read anything.
*/
if (!tracing_is_on() && iter->pos)
break;
mutex_unlock(&iter->mutex);
tracing: Do not busy wait in buffer splice On a !PREEMPT kernel, attempting to use trace-cmd results in a soft lockup: # trace-cmd record -e raw_syscalls:* -F false NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [trace-cmd:61] ... Call Trace: [<ffffffff8105b580>] ? __wake_up_common+0x90/0x90 [<ffffffff81092e25>] wait_on_pipe+0x35/0x40 [<ffffffff810936e3>] tracing_buffers_splice_read+0x2e3/0x3c0 [<ffffffff81093300>] ? tracing_stats_read+0x2a0/0x2a0 [<ffffffff812d10ab>] ? _raw_spin_unlock+0x2b/0x40 [<ffffffff810dc87b>] ? do_read_fault+0x21b/0x290 [<ffffffff810de56a>] ? handle_mm_fault+0x2ba/0xbd0 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff810951e2>] ? trace_buffer_lock_reserve+0x22/0x60 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff8112415d>] do_splice_to+0x6d/0x90 [<ffffffff81126971>] SyS_splice+0x7c1/0x800 [<ffffffff812d1edd>] tracesys_phase2+0xd3/0xd8 The problem is this: tracing_buffers_splice_read() calls ring_buffer_wait() to wait for data in the ring buffers. The buffers are not empty so ring_buffer_wait() returns immediately. But tracing_buffers_splice_read() calls ring_buffer_read_page() with full=1, meaning it only wants to read a full page. When the full page is not available, tracing_buffers_splice_read() tries to wait again with ring_buffer_wait(), which again returns immediately, and so on. Fix this by adding a "full" argument to ring_buffer_wait() which will make ring_buffer_wait() wait until the writer has left the reader's page, i.e. until full-page reads will succeed. Link: http://lkml.kernel.org/r/1415645194-25379-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 3.16+ Fixes: b1169cc69ba9 ("tracing: Remove mock up poll wait function") Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-10 19:46:34 +01:00
ret = wait_on_pipe(iter, false);
mutex_lock(&iter->mutex);
if (ret)
return ret;
}
return 1;
}
/*
* Consumer reader.
*/
static ssize_t
tracing_read_pipe(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_iterator *iter = filp->private_data;
ssize_t sret;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
/*
* Avoid more than one consumer on a single file descriptor
* This is just a matter of traces coherency, the ring buffer itself
* is protected.
*/
mutex_lock(&iter->mutex);
/* return any leftover data */
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
if (sret != -EBUSY)
goto out;
trace_seq_init(&iter->seq);
if (iter->trace->read) {
sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
if (sret)
goto out;
}
waitagain:
sret = tracing_wait_pipe(filp);
if (sret <= 0)
goto out;
/* stop when tracing is finished */
if (trace_empty(iter)) {
sret = 0;
goto out;
}
if (cnt >= PAGE_SIZE)
cnt = PAGE_SIZE - 1;
/* reset all but tr, trace, and overruns */
memset(&iter->seq, 0,
sizeof(struct trace_iterator) -
offsetof(struct trace_iterator, seq));
cpumask_clear(iter->started);
iter->pos = -1;
trace_event_read_lock();
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
trace_access_lock(iter->cpu_file);
while (trace_find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
int save_len = iter->seq.seq.len;
ret = print_trace_line(iter);
if (ret == TRACE_TYPE_PARTIAL_LINE) {
/* don't print partial lines */
iter->seq.seq.len = save_len;
break;
}
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(iter);
if (trace_seq_used(&iter->seq) >= cnt)
break;
/*
* Setting the full flag means we reached the trace_seq buffer
* size and we should leave by partial output condition above.
* One of the trace_seq_* functions is not used properly.
*/
WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
iter->ent->type);
}
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
trace_access_unlock(iter->cpu_file);
trace_event_read_unlock();
/* Now copy what we have to the user */
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
trace_seq_init(&iter->seq);
/*
* If there was nothing to send to user, in spite of consuming trace
* entries, go back to wait for more entries.
*/
if (sret == -EBUSY)
goto waitagain;
out:
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_unlock(&iter->mutex);
return sret;
}
static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
unsigned int idx)
{
__free_page(spd->pages[idx]);
}
static const struct pipe_buf_operations tracing_pipe_buf_ops = {
.can_merge = 0,
.confirm = generic_pipe_buf_confirm,
tracing: Fix buggered tee(2) on tracing_pipe In kernel/trace/trace.c we have this: static void tracing_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { __free_page(buf->page); } static const struct pipe_buf_operations tracing_pipe_buf_ops = { .can_merge = 0, .map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, .confirm = generic_pipe_buf_confirm, .release = tracing_pipe_buf_release, .steal = generic_pipe_buf_steal, .get = generic_pipe_buf_get, }; with void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { page_cache_get(buf->page); } and I don't see anything that would've prevented tee(2) called on the pipe that got stuff spliced into it from that sucker. ->ops->get() will be called, then buf gets copied into target pipe's ->bufs[] and eventually readers get to both copies of the buffer. With get_page(page) look at that page __free_page(page) look at that page __free_page(page) which is not a good thing, to put it mildly. AFAICS, that ought to use the normal generic_pipe_buf_release() (aka page_cache_release(buf->page)), shouldn't it? [ SDR - As trace_pipe just allocates the page with alloc_page(GFP_KERNEL), and doesn't do anything special with it (no LRU logic). The __free_page() should be fine, as it wont actually free a page with reference count. Maybe there's a chance to leak memory? Anyway, This change is at a minimum good for being symmetric with generic_pipe_buf_get, it is fine to add. ] Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> [ SDR - Removed no longer used tracing_pipe_buf_release ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-01-17 13:53:39 +01:00
.release = generic_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
static size_t
tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
{
size_t count;
int save_len;
int ret;
/* Seq buffer is page-sized, exactly what we need. */
for (;;) {
save_len = iter->seq.seq.len;
ret = print_trace_line(iter);
if (trace_seq_has_overflowed(&iter->seq)) {
iter->seq.seq.len = save_len;
break;
}
/*
* This should not be hit, because it should only
* be set if the iter->seq overflowed. But check it
* anyway to be safe.
*/
if (ret == TRACE_TYPE_PARTIAL_LINE) {
iter->seq.seq.len = save_len;
break;
}
count = trace_seq_used(&iter->seq) - save_len;
if (rem < count) {
rem = 0;
iter->seq.seq.len = save_len;
break;
}
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(iter);
rem -= count;
if (!trace_find_next_entry_inc(iter)) {
rem = 0;
iter->ent = NULL;
break;
}
}
return rem;
}
static ssize_t tracing_splice_read_pipe(struct file *filp,
loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len,
unsigned int flags)
{
struct page *pages_def[PIPE_DEF_BUFFERS];
struct partial_page partial_def[PIPE_DEF_BUFFERS];
struct trace_iterator *iter = filp->private_data;
struct splice_pipe_desc spd = {
.pages = pages_def,
.partial = partial_def,
.nr_pages = 0, /* This gets updated below. */
.nr_pages_max = PIPE_DEF_BUFFERS,
.flags = flags,
.ops = &tracing_pipe_buf_ops,
.spd_release = tracing_spd_release_pipe,
};
ssize_t ret;
size_t rem;
unsigned int i;
if (splice_grow_spd(pipe, &spd))
return -ENOMEM;
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_lock(&iter->mutex);
if (iter->trace->splice_read) {
ret = iter->trace->splice_read(iter, filp,
ppos, pipe, len, flags);
if (ret)
goto out_err;
}
ret = tracing_wait_pipe(filp);
if (ret <= 0)
goto out_err;
if (!iter->ent && !trace_find_next_entry_inc(iter)) {
ret = -EFAULT;
goto out_err;
}
trace_event_read_lock();
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
trace_access_lock(iter->cpu_file);
/* Fill as many pages as possible. */
for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
spd.pages[i] = alloc_page(GFP_KERNEL);
if (!spd.pages[i])
break;
rem = tracing_fill_pipe_page(rem, iter);
/* Copy the data into the page, so we can start over. */
ret = trace_seq_to_buffer(&iter->seq,
page_address(spd.pages[i]),
trace_seq_used(&iter->seq));
if (ret < 0) {
__free_page(spd.pages[i]);
break;
}
spd.partial[i].offset = 0;
spd.partial[i].len = trace_seq_used(&iter->seq);
trace_seq_init(&iter->seq);
}
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
trace_access_unlock(iter->cpu_file);
trace_event_read_unlock();
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_unlock(&iter->mutex);
spd.nr_pages = i;
if (i)
ret = splice_to_pipe(pipe, &spd);
else
ret = 0;
out:
splice_shrink_spd(&spd);
return ret;
out_err:
tracing/core: make the read callbacks reentrants Now that several per-cpu files can be read or spliced at the same, we want the read/splice callbacks for tracing files to be reentrants. Until now, a single global mutex (trace_types_lock) serialized the access to tracing_read_pipe(), tracing_splice_read_pipe(), and the seq helpers. Ie: it means that if a user tries to read trace_pipe0 and trace_pipe1 at the same time, the access to the function tracing_read_pipe() is contended and one reader must wait for the other to finish its read call. The trace_type_lock mutex is mostly here to serialize the access to the global current tracer (current_trace), which can be changed concurrently. Although the iter struct keeps a private pointer to this tracer, its callbacks can be changed by another function. The method used here is to not keep anymore private reference to the tracer inside the iterator but to make a copy of it inside the iterator. Then it checks on subsequents read calls if the tracer has changed. This is not costly because the current tracer is not expected to be changed often, so we use a branch prediction for that. Moreover, we add a private mutex to the iterator (there is one iterator per file descriptor) to serialize the accesses in case of multiple consumers per file descriptor (which would be a silly idea from the user). Note that this is not to protect the ring buffer, since the ring buffer already serializes the readers accesses. This is to prevent from traces weirdness in case of concurrent consumers. But these mutexes can be dropped anyway, that would not result in any crash. Just tell me what you think about it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 06:13:16 +01:00
mutex_unlock(&iter->mutex);
goto out;
}
static ssize_t
tracing_entries_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct inode *inode = file_inode(filp);
struct trace_array *tr = inode->i_private;
int cpu = tracing_get_cpu(inode);
char buf[64];
int r = 0;
ssize_t ret;
mutex_lock(&trace_types_lock);
if (cpu == RING_BUFFER_ALL_CPUS) {
int cpu, buf_size_same;
unsigned long size;
size = 0;
buf_size_same = 1;
/* check if all cpu sizes are same */
for_each_tracing_cpu(cpu) {
/* fill in the size from first enabled cpu */
if (size == 0)
size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
buf_size_same = 0;
break;
}
}
if (buf_size_same) {
if (!ring_buffer_expanded)
r = sprintf(buf, "%lu (expanded: %lu)\n",
size >> 10,
trace_buf_size >> 10);
else
r = sprintf(buf, "%lu\n", size >> 10);
} else
r = sprintf(buf, "X\n");
} else
r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
mutex_unlock(&trace_types_lock);
ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
return ret;
}
static ssize_t
tracing_entries_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct inode *inode = file_inode(filp);
struct trace_array *tr = inode->i_private;
unsigned long val;
int ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
/* must have at least 1 entry */
if (!val)
return -EINVAL;
/* value is in KB */
val <<= 10;
ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
if (ret < 0)
return ret;
*ppos += cnt;
return cnt;
}
static ssize_t
tracing_total_entries_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_array *tr = filp->private_data;
char buf[64];
int r, cpu;
unsigned long size = 0, expanded_size = 0;
mutex_lock(&trace_types_lock);
for_each_tracing_cpu(cpu) {
size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
if (!ring_buffer_expanded)
expanded_size += trace_buf_size >> 10;
}
if (ring_buffer_expanded)
r = sprintf(buf, "%lu\n", size);
else
r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
mutex_unlock(&trace_types_lock);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
static ssize_t
tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
/*
* There is no need to read what the user has written, this function
* is just to make sure that there is no error when "echo" is used
*/
*ppos += cnt;
return cnt;
}
static int
tracing_free_buffer_release(struct inode *inode, struct file *filp)
{
struct trace_array *tr = inode->i_private;
/* disable tracing ? */
if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
tracer_tracing_off(tr);
/* resize the ring buffer to 0 */
tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
trace_array_put(tr);
return 0;
}
static ssize_t
tracing_mark_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *fpos)
{
unsigned long addr = (unsigned long)ubuf;
struct trace_array *tr = filp->private_data;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct print_entry *entry;
unsigned long irq_flags;
struct page *pages[2];
void *map_page[2];
int nr_pages = 1;
ssize_t written;
int offset;
int size;
int len;
int ret;
int i;
if (tracing_disabled)
return -EINVAL;
if (!(tr->trace_flags & TRACE_ITER_MARKERS))
return -EINVAL;
if (cnt > TRACE_BUF_SIZE)
cnt = TRACE_BUF_SIZE;
/*
* Userspace is injecting traces into the kernel trace buffer.
* We want to be as non intrusive as possible.
* To do so, we do not want to allocate any special buffers
* or take any locks, but instead write the userspace data
* straight into the ring buffer.
*
* First we need to pin the userspace buffer into memory,
* which, most likely it is, because it just referenced it.
* But there's no guarantee that it is. By using get_user_pages_fast()
* and kmap_atomic/kunmap_atomic() we can get access to the
* pages directly. We then write the data directly into the
* ring buffer.
*/
BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
/* check if we cross pages */
if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
nr_pages = 2;
offset = addr & (PAGE_SIZE - 1);
addr &= PAGE_MASK;
ret = get_user_pages_fast(addr, nr_pages, 0, pages);
if (ret < nr_pages) {
while (--ret >= 0)
put_page(pages[ret]);
written = -EFAULT;
goto out;
}
for (i = 0; i < nr_pages; i++)
map_page[i] = kmap_atomic(pages[i]);
local_save_flags(irq_flags);
size = sizeof(*entry) + cnt + 2; /* possible \n added */
buffer = tr->trace_buffer.buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
irq_flags, preempt_count());
if (!event) {
/* Ring buffer disabled, return as if not open for write */
written = -EBADF;
goto out_unlock;
}
entry = ring_buffer_event_data(event);
entry->ip = _THIS_IP_;
if (nr_pages == 2) {
len = PAGE_SIZE - offset;
memcpy(&entry->buf, map_page[0] + offset, len);
memcpy(&entry->buf[len], map_page[1], cnt - len);
} else
memcpy(&entry->buf, map_page[0] + offset, cnt);
if (entry->buf[cnt - 1] != '\n') {
entry->buf[cnt] = '\n';
entry->buf[cnt + 1] = '\0';
} else
entry->buf[cnt] = '\0';
tracing: Cache comms only after an event occurred Whenever an event is registered, the comm of tasks are saved at every task switch instead of saving them at every event. But if an event isn't executed much, the comm cache will be filled up by tasks that did not record the event and you lose out on the comms that did. Here's an example, if you enable the following events: echo 1 > /debug/tracing/events/kvm/kvm_cr/enable echo 1 > /debug/tracing/events/net/net_dev_xmit/enable Note, there's no kvm running on this machine so the first event will never be triggered, but because it is enabled, the storing of comms will continue. If we now disable the network event: echo 0 > /debug/tracing/events/net/net_dev_xmit/enable and look at the trace: cat /debug/tracing/trace sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 We see that process 2672 which triggered the events has the comm "sshd". But if we run hackbench for a bit and look again: cat /debug/tracing/trace <...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0 <...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0 <...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0 <...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0 The stored "sshd" comm has been flushed out and we get a useless "<...>". But by only storing comms after a trace event occurred, we can run hackbench all day and still get the same output. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-10-11 18:14:25 +02:00
__buffer_unlock_commit(buffer, event);
written = cnt;
*fpos += written;
out_unlock:
for (i = nr_pages - 1; i >= 0; i--) {
kunmap_atomic(map_page[i]);
put_page(pages[i]);
}
out:
return written;
}
static int tracing_clock_show(struct seq_file *m, void *v)
{
struct trace_array *tr = m->private;
int i;
for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
seq_printf(m,
"%s%s%s%s", i ? " " : "",
i == tr->clock_id ? "[" : "", trace_clocks[i].name,
i == tr->clock_id ? "]" : "");
seq_putc(m, '\n');
return 0;
}
static int tracing_set_clock(struct trace_array *tr, const char *clockstr)
{
int i;
for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
if (strcmp(trace_clocks[i].name, clockstr) == 0)
break;
}
if (i == ARRAY_SIZE(trace_clocks))
return -EINVAL;
mutex_lock(&trace_types_lock);
tr->clock_id = i;
ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
/*
* New clock may not be consistent with the previous clock.
* Reset the buffer so that it doesn't have incomparable timestamps.
*/
tracing_reset_online_cpus(&tr->trace_buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
tracing_reset_online_cpus(&tr->max_buffer);
#endif
mutex_unlock(&trace_types_lock);
return 0;
}
static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *fpos)
{
struct seq_file *m = filp->private_data;
struct trace_array *tr = m->private;
char buf[64];
const char *clockstr;
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
clockstr = strstrip(buf);
ret = tracing_set_clock(tr, clockstr);
if (ret)
return ret;
*fpos += cnt;
return cnt;
}
static int tracing_clock_open(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
int ret;
if (tracing_disabled)
return -ENODEV;
if (trace_array_get(tr))
return -ENODEV;
ret = single_open(file, tracing_clock_show, inode->i_private);
if (ret < 0)
trace_array_put(tr);
return ret;
}
struct ftrace_buffer_info {
struct trace_iterator iter;
void *spare;
unsigned int read;
};
#ifdef CONFIG_TRACER_SNAPSHOT
static int tracing_snapshot_open(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
struct seq_file *m;
int ret = 0;
if (trace_array_get(tr) < 0)
return -ENODEV;
if (file->f_mode & FMODE_READ) {
iter = __tracing_open(inode, file, true);
if (IS_ERR(iter))
ret = PTR_ERR(iter);
} else {
/* Writes still need the seq_file to hold the private data */
ret = -ENOMEM;
m = kzalloc(sizeof(*m), GFP_KERNEL);
if (!m)
goto out;
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter) {
kfree(m);
goto out;
}
ret = 0;
iter->tr = tr;
iter->trace_buffer = &tr->max_buffer;
iter->cpu_file = tracing_get_cpu(inode);
m->private = iter;
file->private_data = m;
}
out:
if (ret < 0)
trace_array_put(tr);
return ret;
}
static ssize_t
tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct seq_file *m = filp->private_data;
struct trace_iterator *iter = m->private;
struct trace_array *tr = iter->tr;
unsigned long val;
int ret;
ret = tracing_update_buffers();
if (ret < 0)
return ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
mutex_lock(&trace_types_lock);
if (tr->current_trace->use_max_tr) {
ret = -EBUSY;
goto out;
}
switch (val) {
case 0:
if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
ret = -EINVAL;
break;
}
if (tr->allocated_snapshot)
free_snapshot(tr);
break;
case 1:
/* Only allow per-cpu swap if the ring buffer supports it */
#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
ret = -EINVAL;
break;
}
#endif
if (!tr->allocated_snapshot) {
ret = alloc_snapshot(tr);
if (ret < 0)
break;
}
local_irq_disable();
/* Now, we're going to swap */
if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
update_max_tr(tr, current, smp_processor_id());
else
update_max_tr_single(tr, current, iter->cpu_file);
local_irq_enable();
break;
default:
if (tr->allocated_snapshot) {
if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
tracing_reset_online_cpus(&tr->max_buffer);
else
tracing_reset(&tr->max_buffer, iter->cpu_file);
}
break;
}
if (ret >= 0) {
*ppos += cnt;
ret = cnt;
}
out:
mutex_unlock(&trace_types_lock);
return ret;
}
static int tracing_snapshot_release(struct inode *inode, struct file *file)
{
struct seq_file *m = file->private_data;
int ret;
ret = tracing_release(inode, file);
if (file->f_mode & FMODE_READ)
return ret;
/* If write only, the seq_file is just a stub */
if (m)
kfree(m->private);
kfree(m);
return 0;
}
static int tracing_buffers_open(struct inode *inode, struct file *filp);
static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos);
static int tracing_buffers_release(struct inode *inode, struct file *file);
static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
static int snapshot_raw_open(struct inode *inode, struct file *filp)
{
struct ftrace_buffer_info *info;
int ret;
ret = tracing_buffers_open(inode, filp);
if (ret < 0)
return ret;
info = filp->private_data;
if (info->iter.trace->use_max_tr) {
tracing_buffers_release(inode, filp);
return -EBUSY;
}
info->iter.snapshot = true;
info->iter.trace_buffer = &info->iter.tr->max_buffer;
return ret;
}
#endif /* CONFIG_TRACER_SNAPSHOT */
static const struct file_operations tracing_thresh_fops = {
.open = tracing_open_generic,
.read = tracing_thresh_read,
.write = tracing_thresh_write,
.llseek = generic_file_llseek,
};
#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
static const struct file_operations tracing_max_lat_fops = {
.open = tracing_open_generic,
.read = tracing_max_lat_read,
.write = tracing_max_lat_write,
.llseek = generic_file_llseek,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
#endif
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static const struct file_operations set_tracer_fops = {
.open = tracing_open_generic,
.read = tracing_set_trace_read,
.write = tracing_set_trace_write,
.llseek = generic_file_llseek,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
static const struct file_operations tracing_pipe_fops = {
.open = tracing_open_pipe,
.poll = tracing_poll_pipe,
.read = tracing_read_pipe,
.splice_read = tracing_splice_read_pipe,
.release = tracing_release_pipe,
.llseek = no_llseek,
};
static const struct file_operations tracing_entries_fops = {
.open = tracing_open_generic_tr,
.read = tracing_entries_read,
.write = tracing_entries_write,
.llseek = generic_file_llseek,
.release = tracing_release_generic_tr,
};
static const struct file_operations tracing_total_entries_fops = {
.open = tracing_open_generic_tr,
.read = tracing_total_entries_read,
.llseek = generic_file_llseek,
.release = tracing_release_generic_tr,
};
static const struct file_operations tracing_free_buffer_fops = {
.open = tracing_open_generic_tr,
.write = tracing_free_buffer_write,
.release = tracing_free_buffer_release,
};
static const struct file_operations tracing_mark_fops = {
.open = tracing_open_generic_tr,
.write = tracing_mark_write,
.llseek = generic_file_llseek,
.release = tracing_release_generic_tr,
};
static const struct file_operations trace_clock_fops = {
.open = tracing_clock_open,
.read = seq_read,
.llseek = seq_lseek,
.release = tracing_single_release_tr,
.write = tracing_clock_write,
};
#ifdef CONFIG_TRACER_SNAPSHOT
static const struct file_operations snapshot_fops = {
.open = tracing_snapshot_open,
.read = seq_read,
.write = tracing_snapshot_write,
.llseek = tracing_lseek,
.release = tracing_snapshot_release,
};
static const struct file_operations snapshot_raw_fops = {
.open = snapshot_raw_open,
.read = tracing_buffers_read,
.release = tracing_buffers_release,
.splice_read = tracing_buffers_splice_read,
.llseek = no_llseek,
};
#endif /* CONFIG_TRACER_SNAPSHOT */
static int tracing_buffers_open(struct inode *inode, struct file *filp)
{
struct trace_array *tr = inode->i_private;
struct ftrace_buffer_info *info;
int ret;
if (tracing_disabled)
return -ENODEV;
if (trace_array_get(tr) < 0)
return -ENODEV;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
trace_array_put(tr);
return -ENOMEM;
}
mutex_lock(&trace_types_lock);
info->iter.tr = tr;
info->iter.cpu_file = tracing_get_cpu(inode);
info->iter.trace = tr->current_trace;
info->iter.trace_buffer = &tr->trace_buffer;
info->spare = NULL;
/* Force reading ring buffer for first read */
info->read = (unsigned int)-1;
filp->private_data = info;
tr->current_trace->ref++;
mutex_unlock(&trace_types_lock);
ret = nonseekable_open(inode, filp);
if (ret < 0)
trace_array_put(tr);
return ret;
}
static unsigned int
tracing_buffers_poll(struct file *filp, poll_table *poll_table)
{
struct ftrace_buffer_info *info = filp->private_data;
struct trace_iterator *iter = &info->iter;
return trace_poll(iter, filp, poll_table);
}
static ssize_t
tracing_buffers_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct ftrace_buffer_info *info = filp->private_data;
struct trace_iterator *iter = &info->iter;
ssize_t ret;
ssize_t size;
if (!count)
return 0;
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->tr->current_trace->use_max_tr)
return -EBUSY;
#endif
if (!info->spare)
info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
iter->cpu_file);
if (!info->spare)
return -ENOMEM;
/* Do we have previous read data to read? */
if (info->read < PAGE_SIZE)
goto read;
again:
trace_access_lock(iter->cpu_file);
ret = ring_buffer_read_page(iter->trace_buffer->buffer,
&info->spare,
count,
iter->cpu_file, 0);
trace_access_unlock(iter->cpu_file);
if (ret < 0) {
if (trace_empty(iter)) {
if ((filp->f_flags & O_NONBLOCK))
return -EAGAIN;
tracing: Do not busy wait in buffer splice On a !PREEMPT kernel, attempting to use trace-cmd results in a soft lockup: # trace-cmd record -e raw_syscalls:* -F false NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [trace-cmd:61] ... Call Trace: [<ffffffff8105b580>] ? __wake_up_common+0x90/0x90 [<ffffffff81092e25>] wait_on_pipe+0x35/0x40 [<ffffffff810936e3>] tracing_buffers_splice_read+0x2e3/0x3c0 [<ffffffff81093300>] ? tracing_stats_read+0x2a0/0x2a0 [<ffffffff812d10ab>] ? _raw_spin_unlock+0x2b/0x40 [<ffffffff810dc87b>] ? do_read_fault+0x21b/0x290 [<ffffffff810de56a>] ? handle_mm_fault+0x2ba/0xbd0 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff810951e2>] ? trace_buffer_lock_reserve+0x22/0x60 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff8112415d>] do_splice_to+0x6d/0x90 [<ffffffff81126971>] SyS_splice+0x7c1/0x800 [<ffffffff812d1edd>] tracesys_phase2+0xd3/0xd8 The problem is this: tracing_buffers_splice_read() calls ring_buffer_wait() to wait for data in the ring buffers. The buffers are not empty so ring_buffer_wait() returns immediately. But tracing_buffers_splice_read() calls ring_buffer_read_page() with full=1, meaning it only wants to read a full page. When the full page is not available, tracing_buffers_splice_read() tries to wait again with ring_buffer_wait(), which again returns immediately, and so on. Fix this by adding a "full" argument to ring_buffer_wait() which will make ring_buffer_wait() wait until the writer has left the reader's page, i.e. until full-page reads will succeed. Link: http://lkml.kernel.org/r/1415645194-25379-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 3.16+ Fixes: b1169cc69ba9 ("tracing: Remove mock up poll wait function") Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-10 19:46:34 +01:00
ret = wait_on_pipe(iter, false);
if (ret)
return ret;
goto again;
}
return 0;
}
info->read = 0;
read:
size = PAGE_SIZE - info->read;
if (size > count)
size = count;
ret = copy_to_user(ubuf, info->spare + info->read, size);
if (ret == size)
return -EFAULT;
size -= ret;
*ppos += size;
info->read += size;
return size;
}
static int tracing_buffers_release(struct inode *inode, struct file *file)
{
struct ftrace_buffer_info *info = file->private_data;
struct trace_iterator *iter = &info->iter;
mutex_lock(&trace_types_lock);
iter->tr->current_trace->ref--;
__trace_array_put(iter->tr);
if (info->spare)
ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);
kfree(info);
mutex_unlock(&trace_types_lock);
return 0;
}
struct buffer_ref {
struct ring_buffer *buffer;
void *page;
int ref;
};
static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct buffer_ref *ref = (struct buffer_ref *)buf->private;
if (--ref->ref)
return;
ring_buffer_free_read_page(ref->buffer, ref->page);
kfree(ref);
buf->private = 0;
}
static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct buffer_ref *ref = (struct buffer_ref *)buf->private;
ref->ref++;
}
/* Pipe buffer operations for a buffer. */
static const struct pipe_buf_operations buffer_pipe_buf_ops = {
.can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = buffer_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = buffer_pipe_buf_get,
};
/*
* Callback from splice_to_pipe(), if we need to release some pages
* at the end of the spd in case we error'ed out in filling the pipe.
*/
static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
{
struct buffer_ref *ref =
(struct buffer_ref *)spd->partial[i].private;
if (--ref->ref)
return;
ring_buffer_free_read_page(ref->buffer, ref->page);
kfree(ref);
spd->partial[i].private = 0;
}
static ssize_t
tracing_buffers_splice_read(struct file *file, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct ftrace_buffer_info *info = file->private_data;
struct trace_iterator *iter = &info->iter;
struct partial_page partial_def[PIPE_DEF_BUFFERS];
struct page *pages_def[PIPE_DEF_BUFFERS];
struct splice_pipe_desc spd = {
.pages = pages_def,
.partial = partial_def,
.nr_pages_max = PIPE_DEF_BUFFERS,
.flags = flags,
.ops = &buffer_pipe_buf_ops,
.spd_release = buffer_spd_release,
};
struct buffer_ref *ref;
int entries, size, i;
ssize_t ret = 0;
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->tr->current_trace->use_max_tr)
return -EBUSY;
#endif
if (*ppos & (PAGE_SIZE - 1))
return -EINVAL;
if (len & (PAGE_SIZE - 1)) {
if (len < PAGE_SIZE)
return -EINVAL;
len &= PAGE_MASK;
}
if (splice_grow_spd(pipe, &spd))
return -ENOMEM;
again:
trace_access_lock(iter->cpu_file);
entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
struct page *page;
int r;
ref = kzalloc(sizeof(*ref), GFP_KERNEL);
if (!ref) {
ret = -ENOMEM;
break;
}
ref->ref = 1;
ref->buffer = iter->trace_buffer->buffer;
ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
if (!ref->page) {
ret = -ENOMEM;
kfree(ref);
break;
}
r = ring_buffer_read_page(ref->buffer, &ref->page,
len, iter->cpu_file, 1);
if (r < 0) {
tracing: Use NUMA allocation for per-cpu ring buffer pages The tracing ring buffer is a group of per-cpu ring buffers where allocation and logging is done on a per-cpu basis. The events that are generated on a particular CPU are logged in the corresponding buffer. This is to provide wait-free writes between CPUs and good NUMA node locality while accessing the ring buffer. However, the allocation routines consider NUMA locality only for buffer page metadata and not for the actual buffer page. This causes the pages to be allocated on the NUMA node local to the CPU where the allocation routine is running at the time. This patch fixes the problem by using a NUMA node specific allocation routine so that the pages are allocated from a NUMA node local to the logging CPU. I tested with the getuid_microbench from autotest. It is a simple binary that calls getuid() in a loop and measures the average time for the syscall to complete. The following command was used to test: $ getuid_microbench 1000000 Compared the numbers found on kernel with and without this patch and found that logging latency decreases by 30-50 ns/call. tracing with non-NUMA allocation - 569 ns/call tracing with NUMA allocation - 512 ns/call Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Rubin <mrubin@google.com> Cc: David Sharp <dhsharp@google.com> Link: http://lkml.kernel.org/r/1304470602-20366-1-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-05-04 02:56:42 +02:00
ring_buffer_free_read_page(ref->buffer, ref->page);
kfree(ref);
break;
}
/*
* zero out any left over data, this is going to
* user land.
*/
size = ring_buffer_page_len(ref->page);
if (size < PAGE_SIZE)
memset(ref->page + size, 0, PAGE_SIZE - size);
page = virt_to_page(ref->page);
spd.pages[i] = page;
spd.partial[i].len = PAGE_SIZE;
spd.partial[i].offset = 0;
spd.partial[i].private = (unsigned long)ref;
spd.nr_pages++;
*ppos += PAGE_SIZE;
entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
}
trace_access_unlock(iter->cpu_file);
spd.nr_pages = i;
/* did we read anything? */
if (!spd.nr_pages) {
if (ret)
goto out;
ret = -EAGAIN;
if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
goto out;
tracing: Do not busy wait in buffer splice On a !PREEMPT kernel, attempting to use trace-cmd results in a soft lockup: # trace-cmd record -e raw_syscalls:* -F false NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [trace-cmd:61] ... Call Trace: [<ffffffff8105b580>] ? __wake_up_common+0x90/0x90 [<ffffffff81092e25>] wait_on_pipe+0x35/0x40 [<ffffffff810936e3>] tracing_buffers_splice_read+0x2e3/0x3c0 [<ffffffff81093300>] ? tracing_stats_read+0x2a0/0x2a0 [<ffffffff812d10ab>] ? _raw_spin_unlock+0x2b/0x40 [<ffffffff810dc87b>] ? do_read_fault+0x21b/0x290 [<ffffffff810de56a>] ? handle_mm_fault+0x2ba/0xbd0 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff810951e2>] ? trace_buffer_lock_reserve+0x22/0x60 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff8112415d>] do_splice_to+0x6d/0x90 [<ffffffff81126971>] SyS_splice+0x7c1/0x800 [<ffffffff812d1edd>] tracesys_phase2+0xd3/0xd8 The problem is this: tracing_buffers_splice_read() calls ring_buffer_wait() to wait for data in the ring buffers. The buffers are not empty so ring_buffer_wait() returns immediately. But tracing_buffers_splice_read() calls ring_buffer_read_page() with full=1, meaning it only wants to read a full page. When the full page is not available, tracing_buffers_splice_read() tries to wait again with ring_buffer_wait(), which again returns immediately, and so on. Fix this by adding a "full" argument to ring_buffer_wait() which will make ring_buffer_wait() wait until the writer has left the reader's page, i.e. until full-page reads will succeed. Link: http://lkml.kernel.org/r/1415645194-25379-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 3.16+ Fixes: b1169cc69ba9 ("tracing: Remove mock up poll wait function") Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-10 19:46:34 +01:00
ret = wait_on_pipe(iter, true);
if (ret)
goto out;
tracing: Do not busy wait in buffer splice On a !PREEMPT kernel, attempting to use trace-cmd results in a soft lockup: # trace-cmd record -e raw_syscalls:* -F false NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [trace-cmd:61] ... Call Trace: [<ffffffff8105b580>] ? __wake_up_common+0x90/0x90 [<ffffffff81092e25>] wait_on_pipe+0x35/0x40 [<ffffffff810936e3>] tracing_buffers_splice_read+0x2e3/0x3c0 [<ffffffff81093300>] ? tracing_stats_read+0x2a0/0x2a0 [<ffffffff812d10ab>] ? _raw_spin_unlock+0x2b/0x40 [<ffffffff810dc87b>] ? do_read_fault+0x21b/0x290 [<ffffffff810de56a>] ? handle_mm_fault+0x2ba/0xbd0 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff810951e2>] ? trace_buffer_lock_reserve+0x22/0x60 [<ffffffff81095c80>] ? trace_event_buffer_lock_reserve+0x40/0x80 [<ffffffff8112415d>] do_splice_to+0x6d/0x90 [<ffffffff81126971>] SyS_splice+0x7c1/0x800 [<ffffffff812d1edd>] tracesys_phase2+0xd3/0xd8 The problem is this: tracing_buffers_splice_read() calls ring_buffer_wait() to wait for data in the ring buffers. The buffers are not empty so ring_buffer_wait() returns immediately. But tracing_buffers_splice_read() calls ring_buffer_read_page() with full=1, meaning it only wants to read a full page. When the full page is not available, tracing_buffers_splice_read() tries to wait again with ring_buffer_wait(), which again returns immediately, and so on. Fix this by adding a "full" argument to ring_buffer_wait() which will make ring_buffer_wait() wait until the writer has left the reader's page, i.e. until full-page reads will succeed. Link: http://lkml.kernel.org/r/1415645194-25379-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 3.16+ Fixes: b1169cc69ba9 ("tracing: Remove mock up poll wait function") Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-10 19:46:34 +01:00
goto again;
}
ret = splice_to_pipe(pipe, &spd);
out:
splice_shrink_spd(&spd);
return ret;
}
static const struct file_operations tracing_buffers_fops = {
.open = tracing_buffers_open,
.read = tracing_buffers_read,
.poll = tracing_buffers_poll,
.release = tracing_buffers_release,
.splice_read = tracing_buffers_splice_read,
.llseek = no_llseek,
};
static ssize_t
tracing_stats_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct inode *inode = file_inode(filp);
struct trace_array *tr = inode->i_private;
struct trace_buffer *trace_buf = &tr->trace_buffer;
int cpu = tracing_get_cpu(inode);
struct trace_seq *s;
unsigned long cnt;
unsigned long long t;
unsigned long usec_rem;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "entries: %ld\n", cnt);
cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "overrun: %ld\n", cnt);
cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "commit overrun: %ld\n", cnt);
cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "bytes: %ld\n", cnt);
if (trace_clocks[tr->clock_id].in_ns) {
/* local or global for trace_clock */
t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
usec_rem = do_div(t, USEC_PER_SEC);
trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
t, usec_rem);
t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
usec_rem = do_div(t, USEC_PER_SEC);
trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
} else {
/* counter or tsc mode for trace_clock */
trace_seq_printf(s, "oldest event ts: %llu\n",
ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
trace_seq_printf(s, "now ts: %llu\n",
ring_buffer_time_stamp(trace_buf->buffer, cpu));
}
cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "dropped events: %ld\n", cnt);
cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "read events: %ld\n", cnt);
count = simple_read_from_buffer(ubuf, count, ppos,
s->buffer, trace_seq_used(s));
kfree(s);
return count;
}
static const struct file_operations tracing_stats_fops = {
.open = tracing_open_generic_tr,
.read = tracing_stats_read,
.llseek = generic_file_llseek,
.release = tracing_release_generic_tr,
};
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#ifdef CONFIG_DYNAMIC_FTRACE
int __weak ftrace_arch_read_dyn_info(char *buf, int size)
{
return 0;
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static ssize_t
tracing_read_dyn_info(struct file *filp, char __user *ubuf,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
size_t cnt, loff_t *ppos)
{
static char ftrace_dyn_info_buffer[1024];
static DEFINE_MUTEX(dyn_info_mutex);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
unsigned long *p = filp->private_data;
char *buf = ftrace_dyn_info_buffer;
int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
int r;
mutex_lock(&dyn_info_mutex);
r = sprintf(buf, "%ld ", *p);
r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
buf[r++] = '\n';
r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
mutex_unlock(&dyn_info_mutex);
return r;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static const struct file_operations tracing_dyn_info_fops = {
.open = tracing_open_generic,
.read = tracing_read_dyn_info,
.llseek = generic_file_llseek,
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
};
#endif /* CONFIG_DYNAMIC_FTRACE */
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
static void
ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
{
tracing_snapshot();
}
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static void
ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
unsigned long *count = (long *)data;
if (!*count)
return;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
if (*count != -1)
(*count)--;
tracing_snapshot();
}
static int
ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *data)
{
long count = (long)data;
seq_printf(m, "%ps:", (void *)ip);
seq_puts(m, "snapshot");
if (count == -1)
seq_puts(m, ":unlimited\n");
else
seq_printf(m, ":count=%ld\n", count);
return 0;
}
static struct ftrace_probe_ops snapshot_probe_ops = {
.func = ftrace_snapshot,
.print = ftrace_snapshot_print,
};
static struct ftrace_probe_ops snapshot_count_probe_ops = {
.func = ftrace_count_snapshot,
.print = ftrace_snapshot_print,
};
static int
ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
char *glob, char *cmd, char *param, int enable)
{
struct ftrace_probe_ops *ops;
void *count = (void *)-1;
char *number;
int ret;
/* hash funcs only work with set_ftrace_filter */
if (!enable)
return -EINVAL;
ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
if (glob[0] == '!') {
unregister_ftrace_function_probe_func(glob+1, ops);
return 0;
}
if (!param)
goto out_reg;
number = strsep(&param, ":");
if (!strlen(number))
goto out_reg;
/*
* We use the callback data field (which is a pointer)
* as our counter.
*/
ret = kstrtoul(number, 0, (unsigned long *)&count);
if (ret)
return ret;
out_reg:
ret = register_ftrace_function_probe(glob, ops, count);
if (ret >= 0)
alloc_snapshot(&global_trace);
return ret < 0 ? ret : 0;
}
static struct ftrace_func_command ftrace_snapshot_cmd = {
.name = "snapshot",
.func = ftrace_trace_snapshot_callback,
};
static __init int register_snapshot_cmd(void)
{
return register_ftrace_command(&ftrace_snapshot_cmd);
}
#else
static inline __init int register_snapshot_cmd(void) { return 0; }
#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
static struct dentry *tracing_get_dentry(struct trace_array *tr)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
if (WARN_ON(!tr->dir))
return ERR_PTR(-ENODEV);
/* Top directory uses NULL as the parent */
if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
return NULL;
/* All sub buffers have a descriptor */
return tr->dir;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
{
struct dentry *d_tracer;
if (tr->percpu_dir)
return tr->percpu_dir;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
d_tracer = tracing_get_dentry(tr);
if (IS_ERR(d_tracer))
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
return NULL;
tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
WARN_ONCE(!tr->percpu_dir,
"Could not create tracefs directory 'per_cpu/%d'\n", cpu);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
return tr->percpu_dir;
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
}
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
static struct dentry *
trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
void *data, long cpu, const struct file_operations *fops)
{
struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
if (ret) /* See tracing_get_cpu() */
d_inode(ret)->i_cdev = (void *)(cpu + 1);
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
return ret;
}
static void
tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
{
struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
struct dentry *d_cpu;
char cpu_dir[30]; /* 30 characters should be more than enough */
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
if (!d_percpu)
return;
snprintf(cpu_dir, 30, "cpu%ld", cpu);
d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
if (!d_cpu) {
pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
return;
}
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
/* per cpu trace_pipe */
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
trace_create_cpu_file("trace_pipe", 0444, d_cpu,
tr, cpu, &tracing_pipe_fops);
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
/* per cpu trace */
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
trace_create_cpu_file("trace", 0644, d_cpu,
tr, cpu, &tracing_fops);
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
tr, cpu, &tracing_buffers_fops);
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
trace_create_cpu_file("stats", 0444, d_cpu,
tr, cpu, &tracing_stats_fops);
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
tr, cpu, &tracing_entries_fops);
#ifdef CONFIG_TRACER_SNAPSHOT
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
trace_create_cpu_file("snapshot", 0644, d_cpu,
tr, cpu, &snapshot_fops);
tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-23 17:25:54 +02:00
trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
tr, cpu, &snapshot_raw_fops);
#endif
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
}
#ifdef CONFIG_FTRACE_SELFTEST
/* Let selftest have access to static functions in this file */
#include "trace_selftest.c"
#endif
static ssize_t
trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_option_dentry *topt = filp->private_data;
char *buf;
if (topt->flags->val & topt->opt->bit)
buf = "1\n";
else
buf = "0\n";
return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
}
static ssize_t
trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_option_dentry *topt = filp->private_data;
unsigned long val;
int ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
if (val != 0 && val != 1)
return -EINVAL;
if (!!(topt->flags->val & topt->opt->bit) != val) {
mutex_lock(&trace_types_lock);
ret = __set_tracer_option(topt->tr, topt->flags,
topt->opt, !val);
mutex_unlock(&trace_types_lock);
if (ret)
return ret;
}
*ppos += cnt;
return cnt;
}
static const struct file_operations trace_options_fops = {
.open = tracing_open_generic,
.read = trace_options_read,
.write = trace_options_write,
.llseek = generic_file_llseek,
};
/*
* In order to pass in both the trace_array descriptor as well as the index
* to the flag that the trace option file represents, the trace_array
* has a character array of trace_flags_index[], which holds the index
* of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
* The address of this character array is passed to the flag option file
* read/write callbacks.
*
* In order to extract both the index and the trace_array descriptor,
* get_tr_index() uses the following algorithm.
*
* idx = *ptr;
*
* As the pointer itself contains the address of the index (remember
* index[1] == 1).
*
* Then to get the trace_array descriptor, by subtracting that index
* from the ptr, we get to the start of the index itself.
*
* ptr - idx == &index[0]
*
* Then a simple container_of() from that pointer gets us to the
* trace_array descriptor.
*/
static void get_tr_index(void *data, struct trace_array **ptr,
unsigned int *pindex)
{
*pindex = *(unsigned char *)data;
*ptr = container_of(data - *pindex, struct trace_array,
trace_flags_index);
}
static ssize_t
trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
void *tr_index = filp->private_data;
struct trace_array *tr;
unsigned int index;
char *buf;
get_tr_index(tr_index, &tr, &index);
if (tr->trace_flags & (1 << index))
buf = "1\n";
else
buf = "0\n";
return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
}
static ssize_t
trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
void *tr_index = filp->private_data;
struct trace_array *tr;
unsigned int index;
unsigned long val;
int ret;
get_tr_index(tr_index, &tr, &index);
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
if (val != 0 && val != 1)
return -EINVAL;
mutex_lock(&trace_types_lock);
ret = set_tracer_flag(tr, 1 << index, val);
mutex_unlock(&trace_types_lock);
if (ret < 0)
return ret;
*ppos += cnt;
return cnt;
}
static const struct file_operations trace_options_core_fops = {
.open = tracing_open_generic,
.read = trace_options_core_read,
.write = trace_options_core_write,
.llseek = generic_file_llseek,
};
struct dentry *trace_create_file(const char *name,
umode_t mode,
struct dentry *parent,
void *data,
const struct file_operations *fops)
{
struct dentry *ret;
ret = tracefs_create_file(name, mode, parent, data, fops);
if (!ret)
pr_warn("Could not create tracefs '%s' entry\n", name);
return ret;
}
static struct dentry *trace_options_init_dentry(struct trace_array *tr)
{
struct dentry *d_tracer;
if (tr->options)
return tr->options;
d_tracer = tracing_get_dentry(tr);
if (IS_ERR(d_tracer))
return NULL;
tr->options = tracefs_create_dir("options", d_tracer);
if (!tr->options) {
pr_warn("Could not create tracefs directory 'options'\n");
return NULL;
}
return tr->options;
}
static void
create_trace_option_file(struct trace_array *tr,
struct trace_option_dentry *topt,
struct tracer_flags *flags,
struct tracer_opt *opt)
{
struct dentry *t_options;
t_options = trace_options_init_dentry(tr);
if (!t_options)
return;
topt->flags = flags;
topt->opt = opt;
topt->tr = tr;
topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
&trace_options_fops);
}
static void
create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
{
struct trace_option_dentry *topts;
struct trace_options *tr_topts;
struct tracer_flags *flags;
struct tracer_opt *opts;
int cnt;
int i;
if (!tracer)
return;
flags = tracer->flags;
if (!flags || !flags->opts)
return;
/*
* If this is an instance, only create flags for tracers
* the instance may have.
*/
if (!trace_ok_for_array(tracer, tr))
return;
for (i = 0; i < tr->nr_topts; i++) {
tracing: Make tracer_flags use the right set_flag callback When I was updating the ftrace_stress test of ltp. I encountered a strange phenomemon, excute following steps: echo nop > /sys/kernel/debug/tracing/current_tracer echo 0 > /sys/kernel/debug/tracing/options/funcgraph-cpu bash: echo: write error: Invalid argument check dmesg: [ 1024.903855] nop_test_refuse flag set to 0: we refuse.Now cat trace_options to see the result The reason is that the trace option test will randomly setup trace option under tracing/options no matter what the current_tracer is. but the set_tracer_option is always using the set_flag callback from the current_tracer. This patch adds a pointer to tracer_flags and make it point to the tracer it belongs to. When the option is setup, the set_flag of the right tracer will be used no matter what the the current_tracer is. And the old dummy_tracer_flags is used for all the tracers which doesn't have a tracer_flags, having issue to use it to save the pointer of a tracer. So remove it and use dynamic dummy tracer_flags for tracers needing a dummy tracer_flags, as a result, there are no tracers sharing tracer_flags, so remove the check code. And save the current tracer to trace_option_dentry seems not good as it may waste mem space when mount the debug/trace fs more than one time. Link: http://lkml.kernel.org/r/1457444222-8654-1-git-send-email-chuhu@redhat.com Signed-off-by: Chunyu Hu <chuhu@redhat.com> [ Fixed up function tracer options to work with the change ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-08 14:37:01 +01:00
/* Make sure there's no duplicate flags. */
if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
return;
}
opts = flags->opts;
for (cnt = 0; opts[cnt].name; cnt++)
;
topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
if (!topts)
return;
tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
GFP_KERNEL);
if (!tr_topts) {
kfree(topts);
return;
}
tr->topts = tr_topts;
tr->topts[tr->nr_topts].tracer = tracer;
tr->topts[tr->nr_topts].topts = topts;
tr->nr_topts++;
for (cnt = 0; opts[cnt].name; cnt++) {
create_trace_option_file(tr, &topts[cnt], flags,
&opts[cnt]);
WARN_ONCE(topts[cnt].entry == NULL,
"Failed to create trace option: %s",
opts[cnt].name);
}
}
static struct dentry *
create_trace_option_core_file(struct trace_array *tr,
const char *option, long index)
{
struct dentry *t_options;
t_options = trace_options_init_dentry(tr);
if (!t_options)
return NULL;
return trace_create_file(option, 0644, t_options,
(void *)&tr->trace_flags_index[index],
&trace_options_core_fops);
}
static void create_trace_options_dir(struct trace_array *tr)
{
struct dentry *t_options;
bool top_level = tr == &global_trace;
int i;
t_options = trace_options_init_dentry(tr);
if (!t_options)
return;
for (i = 0; trace_options[i]; i++) {
if (top_level ||
!((1 << i) & TOP_LEVEL_TRACE_FLAGS))
create_trace_option_core_file(tr, trace_options[i], i);
}
}
static ssize_t
rb_simple_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_array *tr = filp->private_data;
char buf[64];
int r;
r = tracer_tracing_is_on(tr);
r = sprintf(buf, "%d\n", r);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
static ssize_t
rb_simple_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_array *tr = filp->private_data;
struct ring_buffer *buffer = tr->trace_buffer.buffer;
unsigned long val;
int ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
if (buffer) {
mutex_lock(&trace_types_lock);
if (val) {
tracer_tracing_on(tr);
if (tr->current_trace->start)
tr->current_trace->start(tr);
} else {
tracer_tracing_off(tr);
if (tr->current_trace->stop)
tr->current_trace->stop(tr);
}
mutex_unlock(&trace_types_lock);
}
(*ppos)++;
return cnt;
}
static const struct file_operations rb_simple_fops = {
.open = tracing_open_generic_tr,
.read = rb_simple_read,
.write = rb_simple_write,
.release = tracing_release_generic_tr,
.llseek = default_llseek,
};
struct dentry *trace_instance_dir;
static void
init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
static int
allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
{
enum ring_buffer_flags rb_flags;
rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
buf->tr = tr;
buf->buffer = ring_buffer_alloc(size, rb_flags);
if (!buf->buffer)
return -ENOMEM;
buf->data = alloc_percpu(struct trace_array_cpu);
if (!buf->data) {
ring_buffer_free(buf->buffer);
return -ENOMEM;
}
/* Allocate the first page for all buffers */
set_buffer_entries(&tr->trace_buffer,
ring_buffer_size(tr->trace_buffer.buffer, 0));
return 0;
}
static int allocate_trace_buffers(struct trace_array *tr, int size)
{
int ret;
ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
if (ret)
return ret;
#ifdef CONFIG_TRACER_MAX_TRACE
ret = allocate_trace_buffer(tr, &tr->max_buffer,
allocate_snapshot ? size : 1);
if (WARN_ON(ret)) {
ring_buffer_free(tr->trace_buffer.buffer);
free_percpu(tr->trace_buffer.data);
return -ENOMEM;
}
tr->allocated_snapshot = allocate_snapshot;
/*
* Only the top level trace array gets its snapshot allocated
* from the kernel command line.
*/
allocate_snapshot = false;
#endif
return 0;
}
static void free_trace_buffer(struct trace_buffer *buf)
{
if (buf->buffer) {
ring_buffer_free(buf->buffer);
buf->buffer = NULL;
free_percpu(buf->data);
buf->data = NULL;
}
}
static void free_trace_buffers(struct trace_array *tr)
{
if (!tr)
return;
free_trace_buffer(&tr->trace_buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
free_trace_buffer(&tr->max_buffer);
#endif
}
static void init_trace_flags_index(struct trace_array *tr)
{
int i;
/* Used by the trace options files */
for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
tr->trace_flags_index[i] = i;
}
static void __update_tracer_options(struct trace_array *tr)
{
struct tracer *t;
for (t = trace_types; t; t = t->next)
add_tracer_options(tr, t);
}
static void update_tracer_options(struct trace_array *tr)
{
mutex_lock(&trace_types_lock);
__update_tracer_options(tr);
mutex_unlock(&trace_types_lock);
}
tracing: Have mkdir and rmdir be part of tracefs The tracing "instances" directory can create sub tracing buffers with mkdir, and remove them with rmdir. As a mkdir will also create all the files and directories that control the sub buffer the inode mutexes need to be released before this is done, to avoid deadlocks. It is better to let the tracing system unlock the inode mutexes before calling the functions that create the files within the new directory (or deletes the files from the one being destroyed). Now that tracing has been converted over to tracefs, the tracefs file system can be modified to accommodate this feature. It still releases the locks, but the filesystem itself can take care of the ugly business and let the user just do what it needs. The tracing system now attaches a descriptor to the directory dentry that can have userspace create or remove sub directories. If this descriptor does not exist for a dentry, then that dentry can not be used to create other directories. This descriptor holds a mkdir and rmdir method that only takes a character string as an argument. The tracefs file system will first make a copy of the dentry name before releasing the locks. Then it will pass the copied name to the methods. It is up to the tracing system that supplied the methods to handle races with duplicate names and such as all the inode mutexes would be released when the functions are called. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-01-21 16:01:39 +01:00
static int instance_mkdir(const char *name)
{
struct trace_array *tr;
int ret;
mutex_lock(&trace_types_lock);
ret = -EEXIST;
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (tr->name && strcmp(tr->name, name) == 0)
goto out_unlock;
}
ret = -ENOMEM;
tr = kzalloc(sizeof(*tr), GFP_KERNEL);
if (!tr)
goto out_unlock;
tr->name = kstrdup(name, GFP_KERNEL);
if (!tr->name)
goto out_free_tr;
if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
goto out_free_tr;
tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
raw_spin_lock_init(&tr->start_lock);
tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
tr->current_trace = &nop_trace;
INIT_LIST_HEAD(&tr->systems);
INIT_LIST_HEAD(&tr->events);
if (allocate_trace_buffers(tr, trace_buf_size) < 0)
goto out_free_tr;
tr->dir = tracefs_create_dir(name, trace_instance_dir);
if (!tr->dir)
goto out_free_tr;
ret = event_trace_add_tracer(tr->dir, tr);
if (ret) {
tracefs_remove_recursive(tr->dir);
goto out_free_tr;
}
init_tracer_tracefs(tr, tr->dir);
init_trace_flags_index(tr);
__update_tracer_options(tr);
list_add(&tr->list, &ftrace_trace_arrays);
mutex_unlock(&trace_types_lock);
return 0;
out_free_tr:
free_trace_buffers(tr);
free_cpumask_var(tr->tracing_cpumask);
kfree(tr->name);
kfree(tr);
out_unlock:
mutex_unlock(&trace_types_lock);
return ret;
}
tracing: Have mkdir and rmdir be part of tracefs The tracing "instances" directory can create sub tracing buffers with mkdir, and remove them with rmdir. As a mkdir will also create all the files and directories that control the sub buffer the inode mutexes need to be released before this is done, to avoid deadlocks. It is better to let the tracing system unlock the inode mutexes before calling the functions that create the files within the new directory (or deletes the files from the one being destroyed). Now that tracing has been converted over to tracefs, the tracefs file system can be modified to accommodate this feature. It still releases the locks, but the filesystem itself can take care of the ugly business and let the user just do what it needs. The tracing system now attaches a descriptor to the directory dentry that can have userspace create or remove sub directories. If this descriptor does not exist for a dentry, then that dentry can not be used to create other directories. This descriptor holds a mkdir and rmdir method that only takes a character string as an argument. The tracefs file system will first make a copy of the dentry name before releasing the locks. Then it will pass the copied name to the methods. It is up to the tracing system that supplied the methods to handle races with duplicate names and such as all the inode mutexes would be released when the functions are called. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-01-21 16:01:39 +01:00
static int instance_rmdir(const char *name)
{
struct trace_array *tr;
int found = 0;
int ret;
int i;
mutex_lock(&trace_types_lock);
ret = -ENODEV;
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (tr->name && strcmp(tr->name, name) == 0) {
found = 1;
break;
}
}
if (!found)
goto out_unlock;
ret = -EBUSY;
if (tr->ref || (tr->current_trace && tr->current_trace->ref))
goto out_unlock;
list_del(&tr->list);
/* Disable all the flags that were enabled coming in */
for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
if ((1 << i) & ZEROED_TRACE_FLAGS)
set_tracer_flag(tr, 1 << i, 0);
}
tracing_set_nop(tr);
event_trace_del_tracer(tr);
ftrace_destroy_function_files(tr);
tracefs_remove_recursive(tr->dir);
free_trace_buffers(tr);
for (i = 0; i < tr->nr_topts; i++) {
kfree(tr->topts[i].topts);
}
kfree(tr->topts);
kfree(tr->name);
kfree(tr);
ret = 0;
out_unlock:
mutex_unlock(&trace_types_lock);
return ret;
}
static __init void create_trace_instances(struct dentry *d_tracer)
{
tracing: Have mkdir and rmdir be part of tracefs The tracing "instances" directory can create sub tracing buffers with mkdir, and remove them with rmdir. As a mkdir will also create all the files and directories that control the sub buffer the inode mutexes need to be released before this is done, to avoid deadlocks. It is better to let the tracing system unlock the inode mutexes before calling the functions that create the files within the new directory (or deletes the files from the one being destroyed). Now that tracing has been converted over to tracefs, the tracefs file system can be modified to accommodate this feature. It still releases the locks, but the filesystem itself can take care of the ugly business and let the user just do what it needs. The tracing system now attaches a descriptor to the directory dentry that can have userspace create or remove sub directories. If this descriptor does not exist for a dentry, then that dentry can not be used to create other directories. This descriptor holds a mkdir and rmdir method that only takes a character string as an argument. The tracefs file system will first make a copy of the dentry name before releasing the locks. Then it will pass the copied name to the methods. It is up to the tracing system that supplied the methods to handle races with duplicate names and such as all the inode mutexes would be released when the functions are called. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-01-21 16:01:39 +01:00
trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
instance_mkdir,
instance_rmdir);
if (WARN_ON(!trace_instance_dir))
return;
}
static void
init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
{
int cpu;
trace_create_file("available_tracers", 0444, d_tracer,
tr, &show_traces_fops);
trace_create_file("current_tracer", 0644, d_tracer,
tr, &set_tracer_fops);
trace_create_file("tracing_cpumask", 0644, d_tracer,
tr, &tracing_cpumask_fops);
trace_create_file("trace_options", 0644, d_tracer,
tr, &tracing_iter_fops);
trace_create_file("trace", 0644, d_tracer,
tr, &tracing_fops);
trace_create_file("trace_pipe", 0444, d_tracer,
tr, &tracing_pipe_fops);
trace_create_file("buffer_size_kb", 0644, d_tracer,
tr, &tracing_entries_fops);
trace_create_file("buffer_total_size_kb", 0444, d_tracer,
tr, &tracing_total_entries_fops);
trace_create_file("free_buffer", 0200, d_tracer,
tr, &tracing_free_buffer_fops);
trace_create_file("trace_marker", 0220, d_tracer,
tr, &tracing_mark_fops);
trace_create_file("trace_clock", 0644, d_tracer, tr,
&trace_clock_fops);
trace_create_file("tracing_on", 0644, d_tracer,
tr, &rb_simple_fops);
create_trace_options_dir(tr);
#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
trace_create_file("tracing_max_latency", 0644, d_tracer,
&tr->max_latency, &tracing_max_lat_fops);
#endif
if (ftrace_create_function_files(tr, d_tracer))
WARN(1, "Could not allocate function filter files");
#ifdef CONFIG_TRACER_SNAPSHOT
trace_create_file("snapshot", 0644, d_tracer,
tr, &snapshot_fops);
#endif
for_each_tracing_cpu(cpu)
tracing_init_tracefs_percpu(tr, cpu);
ftrace_init_tracefs(tr, d_tracer);
}
static struct vfsmount *trace_automount(void *ingore)
{
struct vfsmount *mnt;
struct file_system_type *type;
/*
* To maintain backward compatibility for tools that mount
* debugfs to get to the tracing facility, tracefs is automatically
* mounted to the debugfs/tracing directory.
*/
type = get_fs_type("tracefs");
if (!type)
return NULL;
mnt = vfs_kern_mount(type, 0, "tracefs", NULL);
put_filesystem(type);
if (IS_ERR(mnt))
return NULL;
mntget(mnt);
return mnt;
}
/**
* tracing_init_dentry - initialize top level trace array
*
* This is called when creating files or directories in the tracing
* directory. It is called via fs_initcall() by any of the boot up code
* and expects to return the dentry of the top level tracing directory.
*/
struct dentry *tracing_init_dentry(void)
{
struct trace_array *tr = &global_trace;
/* The top level trace array uses NULL as parent */
if (tr->dir)
return NULL;
if (WARN_ON(!tracefs_initialized()) ||
(IS_ENABLED(CONFIG_DEBUG_FS) &&
WARN_ON(!debugfs_initialized())))
return ERR_PTR(-ENODEV);
/*
* As there may still be users that expect the tracing
* files to exist in debugfs/tracing, we must automount
* the tracefs file system there, so older tools still
* work with the newer kerenl.
*/
tr->dir = debugfs_create_automount("tracing", NULL,
trace_automount, NULL);
if (!tr->dir) {
pr_warn_once("Could not create debugfs directory 'tracing'\n");
return ERR_PTR(-ENOMEM);
}
return NULL;
}
tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values Several tracepoints use the helper functions __print_symbolic() or __print_flags() and pass in enums that do the mapping between the binary data stored and the value to print. This works well for reading the ASCII trace files, but when the data is read via userspace tools such as perf and trace-cmd, the conversion of the binary value to a human string format is lost if an enum is used, as userspace does not have access to what the ENUM is. For example, the tracepoint trace_tlb_flush() has: __print_symbolic(REC->reason, { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }) Which maps the enum values to the strings they represent. But perf and trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would not be able to map it. With TRACE_DEFINE_ENUM(), developers can place these in the event header files and ftrace will convert the enums to their values: By adding: TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH); TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN); $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format [...] __print_symbolic(REC->reason, { 0, "flush on task switch" }, { 1, "remote shootdown" }, { 2, "local shootdown" }, { 3, "local mm shootdown" }) The above is what userspace expects to see, and tools do not need to be modified to parse them. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Cc: Guilherme Cox <cox@computer.org> Cc: Tony Luck <tony.luck@gmail.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-03-24 22:58:09 +01:00
extern struct trace_enum_map *__start_ftrace_enum_maps[];
extern struct trace_enum_map *__stop_ftrace_enum_maps[];
static void __init trace_enum_init(void)
{
int len;
len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
trace_insert_enum_map(NULL, __start_ftrace_enum_maps, len);
}
#ifdef CONFIG_MODULES
static void trace_module_add_enums(struct module *mod)
{
if (!mod->num_trace_enums)
return;
/*
* Modules with bad taint do not have events created, do
* not bother with enums either.
*/
if (trace_module_has_bad_taint(mod))
return;
trace_insert_enum_map(mod, mod->trace_enums, mod->num_trace_enums);
}
#ifdef CONFIG_TRACE_ENUM_MAP_FILE
static void trace_module_remove_enums(struct module *mod)
{
union trace_enum_map_item *map;
union trace_enum_map_item **last = &trace_enum_maps;
if (!mod->num_trace_enums)
return;
mutex_lock(&trace_enum_mutex);
map = trace_enum_maps;
while (map) {
if (map->head.mod == mod)
break;
map = trace_enum_jmp_to_tail(map);
last = &map->tail.next;
map = map->tail.next;
}
if (!map)
goto out;
*last = trace_enum_jmp_to_tail(map)->tail.next;
kfree(map);
out:
mutex_unlock(&trace_enum_mutex);
}
#else
static inline void trace_module_remove_enums(struct module *mod) { }
#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
static int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
switch (val) {
case MODULE_STATE_COMING:
trace_module_add_enums(mod);
break;
case MODULE_STATE_GOING:
trace_module_remove_enums(mod);
break;
}
return 0;
tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values Several tracepoints use the helper functions __print_symbolic() or __print_flags() and pass in enums that do the mapping between the binary data stored and the value to print. This works well for reading the ASCII trace files, but when the data is read via userspace tools such as perf and trace-cmd, the conversion of the binary value to a human string format is lost if an enum is used, as userspace does not have access to what the ENUM is. For example, the tracepoint trace_tlb_flush() has: __print_symbolic(REC->reason, { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }) Which maps the enum values to the strings they represent. But perf and trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would not be able to map it. With TRACE_DEFINE_ENUM(), developers can place these in the event header files and ftrace will convert the enums to their values: By adding: TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH); TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN); $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format [...] __print_symbolic(REC->reason, { 0, "flush on task switch" }, { 1, "remote shootdown" }, { 2, "local shootdown" }, { 3, "local mm shootdown" }) The above is what userspace expects to see, and tools do not need to be modified to parse them. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Cc: Guilherme Cox <cox@computer.org> Cc: Tony Luck <tony.luck@gmail.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-03-24 22:58:09 +01:00
}
static struct notifier_block trace_module_nb = {
.notifier_call = trace_module_notify,
.priority = 0,
};
#endif /* CONFIG_MODULES */
static __init int tracer_init_tracefs(void)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
struct dentry *d_tracer;
tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-01-06 13:08:50 +01:00
trace_access_lock_init();
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
d_tracer = tracing_init_dentry();
if (IS_ERR(d_tracer))
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
init_tracer_tracefs(&global_trace, d_tracer);
ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
trace_create_file("tracing_thresh", 0644, d_tracer,
&global_trace, &tracing_thresh_fops);
trace_create_file("README", 0444, d_tracer,
NULL, &tracing_readme_fops);
trace_create_file("saved_cmdlines", 0444, d_tracer,
NULL, &tracing_saved_cmdlines_fops);
trace_create_file("saved_cmdlines_size", 0644, d_tracer,
NULL, &tracing_saved_cmdlines_size_fops);
tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values Several tracepoints use the helper functions __print_symbolic() or __print_flags() and pass in enums that do the mapping between the binary data stored and the value to print. This works well for reading the ASCII trace files, but when the data is read via userspace tools such as perf and trace-cmd, the conversion of the binary value to a human string format is lost if an enum is used, as userspace does not have access to what the ENUM is. For example, the tracepoint trace_tlb_flush() has: __print_symbolic(REC->reason, { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }) Which maps the enum values to the strings they represent. But perf and trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would not be able to map it. With TRACE_DEFINE_ENUM(), developers can place these in the event header files and ftrace will convert the enums to their values: By adding: TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH); TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN); $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format [...] __print_symbolic(REC->reason, { 0, "flush on task switch" }, { 1, "remote shootdown" }, { 2, "local shootdown" }, { 3, "local mm shootdown" }) The above is what userspace expects to see, and tools do not need to be modified to parse them. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Cc: Guilherme Cox <cox@computer.org> Cc: Tony Luck <tony.luck@gmail.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-03-24 22:58:09 +01:00
trace_enum_init();
trace_create_enum_file(d_tracer);
#ifdef CONFIG_MODULES
register_module_notifier(&trace_module_nb);
#endif
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#ifdef CONFIG_DYNAMIC_FTRACE
trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
#endif
tracing/core: introduce per cpu tracing files Impact: split up tracing output per cpu Currently, on the tracing debugfs directory, three files are available to the user to let him extracting the trace output: - trace is an iterator through the ring-buffer. It's a reader but not a consumer It doesn't block when no more traces are available. - trace pretty similar to the former, except that it adds more informations such as prempt count, irq flag, ... - trace_pipe is a reader and a consumer, it will also block waiting for traces if necessary (heh, yes it's a pipe). The traces coming from different cpus are curretly mixed up inside these files. Sometimes it messes up the informations, sometimes it's useful, depending on what does the tracer capture. The tracing_cpumask file is useful to filter the output and select only the traces captured a custom defined set of cpus. But still it is not enough powerful to extract at the same time one trace buffer per cpu. So this patch creates a new directory: /debug/tracing/per_cpu/. Inside this directory, you will now find one trace_pipe file and one trace file per cpu. Which means if you have two cpus, you will have: trace0 trace1 trace_pipe0 trace_pipe1 And of course, reading these files will have the same effect than with the usual tracing files, except that you will only see the traces from the given cpu. The original all-in-one cpu trace file are still available on their original place. Until now, only one consumer was allowed on trace_pipe to avoid racy consuming on the ring-buffer. Now the approach changed a bit, you can have only one consumer per cpu. Which means you are allowed to read concurrently trace_pipe0 and trace_pipe1 But you can't have two readers on trace_pipe0 or trace_pipe1. Following the same logic, if there is one reader on the common trace_pipe, you can not have at the same time another reader on trace_pipe0 or in trace_pipe1. Because in trace_pipe is already a consumer in all cpu buffers in essence. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 03:22:28 +01:00
create_trace_instances(d_tracer);
update_tracer_options(&global_trace);
return 0;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
static int trace_panic_handler(struct notifier_block *this,
unsigned long event, void *unused)
{
if (ftrace_dump_on_oops)
ftrace_dump(ftrace_dump_on_oops);
return NOTIFY_OK;
}
static struct notifier_block trace_panic_notifier = {
.notifier_call = trace_panic_handler,
.next = NULL,
.priority = 150 /* priority: INT_MAX >= x >= 0 */
};
static int trace_die_handler(struct notifier_block *self,
unsigned long val,
void *data)
{
switch (val) {
case DIE_OOPS:
if (ftrace_dump_on_oops)
ftrace_dump(ftrace_dump_on_oops);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block trace_die_notifier = {
.notifier_call = trace_die_handler,
.priority = 200
};
/*
* printk is set to max of 1024, we really don't need it that big.
* Nothing should be printing 1000 characters anyway.
*/
#define TRACE_MAX_PRINT 1000
/*
* Define here KERN_TRACE so that we have one place to modify
* it if we decide to change what log level the ftrace dump
* should be at.
*/
#define KERN_TRACE KERN_EMERG
void
trace_printk_seq(struct trace_seq *s)
{
/* Probably should print a warning here. */
if (s->seq.len >= TRACE_MAX_PRINT)
s->seq.len = TRACE_MAX_PRINT;
/*
* More paranoid code. Although the buffer size is set to
* PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
* an extra layer of protection.
*/
if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
s->seq.len = s->seq.size - 1;
/* should be zero ended, but we are paranoid. */
s->buffer[s->seq.len] = 0;
printk(KERN_TRACE "%s", s->buffer);
trace_seq_init(s);
}
void trace_init_global_iter(struct trace_iterator *iter)
{
iter->tr = &global_trace;
iter->trace = iter->tr->current_trace;
iter->cpu_file = RING_BUFFER_ALL_CPUS;
iter->trace_buffer = &global_trace.trace_buffer;
if (iter->trace && iter->trace->open)
iter->trace->open(iter);
/* Annotate start of buffers if we had overruns */
if (ring_buffer_overruns(iter->trace_buffer->buffer))
iter->iter_flags |= TRACE_FILE_ANNOTATE;
/* Output in nanoseconds only if we are using a clock in nanoseconds. */
if (trace_clocks[iter->tr->clock_id].in_ns)
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
}
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
{
/* use static because iter can be a bit big for the stack */
static struct trace_iterator iter;
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
static atomic_t dump_running;
struct trace_array *tr = &global_trace;
unsigned int old_userobj;
unsigned long flags;
int cnt = 0, cpu;
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
/* Only allow one dump user at a time. */
if (atomic_inc_return(&dump_running) != 1) {
atomic_dec(&dump_running);
return;
}
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
/*
* Always turn off tracing when we dump.
* We don't need to show trace output of what happens
* between multiple crashes.
*
* If the user does a sysrq-z, then they can re-enable
* tracing with echo 1 > tracing_on.
*/
tracing_off();
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
local_irq_save(flags);
/* Simulate the iterator */
trace_init_global_iter(&iter);
for_each_tracing_cpu(cpu) {
atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
}
old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
/* don't look at user memory in panic mode */
tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
switch (oops_dump_mode) {
case DUMP_ALL:
iter.cpu_file = RING_BUFFER_ALL_CPUS;
break;
case DUMP_ORIG:
iter.cpu_file = raw_smp_processor_id();
break;
case DUMP_NONE:
goto out_enable;
default:
printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
iter.cpu_file = RING_BUFFER_ALL_CPUS;
}
printk(KERN_TRACE "Dumping ftrace buffer:\n");
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
/* Did function tracer already get disabled? */
if (ftrace_is_dead()) {
printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
printk("# MAY BE MISSING FUNCTION EVENTS\n");
}
/*
* We need to stop all tracing on all CPUS to read the
* the next buffer. This is a bit expensive, but is
* not done often. We fill all what we can read,
* and then release the locks again.
*/
while (!trace_empty(&iter)) {
if (!cnt)
printk(KERN_TRACE "---------------------------------\n");
cnt++;
/* reset all but tr, trace, and overruns */
memset(&iter.seq, 0,
sizeof(struct trace_iterator) -
offsetof(struct trace_iterator, seq));
iter.iter_flags |= TRACE_FILE_LAT_FMT;
iter.pos = -1;
if (trace_find_next_entry_inc(&iter) != NULL) {
int ret;
ret = print_trace_line(&iter);
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(&iter);
}
touch_nmi_watchdog();
trace_printk_seq(&iter.seq);
}
if (!cnt)
printk(KERN_TRACE " (ftrace buffer empty)\n");
else
printk(KERN_TRACE "---------------------------------\n");
out_enable:
tr->trace_flags |= old_userobj;
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
for_each_tracing_cpu(cpu) {
atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
}
tracing: Fix ftrace_dump() ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 18:10:35 +01:00
atomic_dec(&dump_running);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(ftrace_dump);
__init static int tracer_alloc_buffers(void)
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
{
int ring_buf_size;
int ret = -ENOMEM;
/*
* Make sure we don't accidently add more trace options
* than we have bits for.
*/
BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
goto out;
if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
goto out_free_buffer_mask;
2011-09-22 20:01:55 +02:00
/* Only allocate trace_printk buffers if a trace_printk exists */
if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
/* Must be called before global_trace.buffer is allocated */
2011-09-22 20:01:55 +02:00
trace_printk_init_buffers();
/* To save memory, keep the ring buffer size to its minimum */
if (ring_buffer_expanded)
ring_buf_size = trace_buf_size;
else
ring_buf_size = 1;
cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
raw_spin_lock_init(&global_trace.start_lock);
/* Used for event triggers */
temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
if (!temp_buffer)
goto out_free_cpumask;
if (trace_create_savedcmd() < 0)
goto out_free_temp_buffer;
/* TODO: make the number of buffers hot pluggable with CPUS */
if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
WARN_ON(1);
goto out_free_savedcmd;
}
if (global_trace.buffer_disabled)
tracing_off();
if (trace_boot_clock) {
ret = tracing_set_clock(&global_trace, trace_boot_clock);
if (ret < 0)
pr_warn("Trace clock %s not defined, going back to default\n",
trace_boot_clock);
}
/*
* register_tracer() might reference current_trace, so it
* needs to be set before we register anything. This is
* just a bootstrap of current_trace anyway.
*/
global_trace.current_trace = &nop_trace;
global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
ftrace_init_global_array_ops(&global_trace);
init_trace_flags_index(&global_trace);
register_tracer(&nop_trace);
/* All seems OK, enable tracing */
tracing_disabled = 0;
atomic_notifier_chain_register(&panic_notifier_list,
&trace_panic_notifier);
register_die_notifier(&trace_die_notifier);
global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
INIT_LIST_HEAD(&global_trace.systems);
INIT_LIST_HEAD(&global_trace.events);
list_add(&global_trace.list, &ftrace_trace_arrays);
apply_trace_boot_options();
register_snapshot_cmd();
return 0;
out_free_savedcmd:
free_saved_cmdlines_buffer(savedcmd);
out_free_temp_buffer:
ring_buffer_free(temp_buffer);
out_free_cpumask:
free_cpumask_var(global_trace.tracing_cpumask);
out_free_buffer_mask:
free_cpumask_var(tracing_buffer_mask);
out:
return ret;
ftrace: latency tracer infrastructure This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:20:42 +02:00
}
void __init trace_init(void)
{
if (tracepoint_printk) {
tracepoint_print_iter =
kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
if (WARN_ON(!tracepoint_print_iter))
tracepoint_printk = 0;
}
tracer_alloc_buffers();
tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values Several tracepoints use the helper functions __print_symbolic() or __print_flags() and pass in enums that do the mapping between the binary data stored and the value to print. This works well for reading the ASCII trace files, but when the data is read via userspace tools such as perf and trace-cmd, the conversion of the binary value to a human string format is lost if an enum is used, as userspace does not have access to what the ENUM is. For example, the tracepoint trace_tlb_flush() has: __print_symbolic(REC->reason, { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }) Which maps the enum values to the strings they represent. But perf and trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would not be able to map it. With TRACE_DEFINE_ENUM(), developers can place these in the event header files and ftrace will convert the enums to their values: By adding: TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH); TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN); $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format [...] __print_symbolic(REC->reason, { 0, "flush on task switch" }, { 1, "remote shootdown" }, { 2, "local shootdown" }, { 3, "local mm shootdown" }) The above is what userspace expects to see, and tools do not need to be modified to parse them. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Cc: Guilherme Cox <cox@computer.org> Cc: Tony Luck <tony.luck@gmail.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-03-24 22:58:09 +01:00
trace_event_init();
}
__init static int clear_boot_tracer(void)
{
/*
* The default tracer at boot buffer is an init section.
* This function is called in lateinit. If we did not
* find the boot tracer, then clear it out, to prevent
* later registration from accessing the buffer that is
* about to be freed.
*/
if (!default_bootup_tracer)
return 0;
printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
default_bootup_tracer);
default_bootup_tracer = NULL;
return 0;
}
fs_initcall(tracer_init_tracefs);
late_initcall(clear_boot_tracer);