Commit Graph

30 Commits

Author SHA1 Message Date
Arnaldo Carvalho de Melo 51a763dd84 tracing: Introduce trace_buffer_{lock_reserve,unlock_commit}
Impact: new API

These new functions do what previously was being open coded, reducing
the number of details ftrace plugin writers have to worry about.

It also standardizes the handling of stacktrace, userstacktrace and
other trace options we may introduce in the future.

With this patch, for instance, the blk tracer (and some others already
in the tree) can use the "userstacktrace" /d/tracing/trace_options
facility.

$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
  trace_vprintk              |   -5
  trace_graph_return         |  -22
  trace_graph_entry          |  -26
  trace_function             |  -45
  __ftrace_trace_stack       |  -27
  ftrace_trace_userstack     |  -29
  tracing_sched_switch_trace |  -66
  tracing_stop               |   +1
  trace_seq_to_user          |   -1
  ftrace_trace_special       |  -63
  ftrace_special             |   +1
  tracing_sched_wakeup_trace |  -70
  tracing_reset_online_cpus  |   -1
 13 functions changed, 2 bytes added, 355 bytes removed, diff: -353

linux-2.6-tip/block/blktrace.c:
  __blk_add_trace |  -58
 1 function changed, 58 bytes removed, diff: -58

linux-2.6-tip/kernel/trace/trace.c:
  trace_buffer_lock_reserve  |  +88
  trace_buffer_unlock_commit |  +86
 2 functions changed, 174 bytes added, diff: +174

/tmp/vmlinux.after:
 16 functions changed, 176 bytes added, 413 bytes removed, diff: -237

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:41 +01:00
Arnaldo Carvalho de Melo 0a9877514c ring_buffer: remove unused flags parameter
Impact: API change, cleanup

>From ring_buffer_{lock_reserve,unlock_commit}.

$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
  trace_vprintk              |  -14
  trace_graph_return         |  -14
  trace_graph_entry          |  -10
  trace_function             |   -8
  __ftrace_trace_stack       |   -8
  ftrace_trace_userstack     |   -8
  tracing_sched_switch_trace |   -8
  ftrace_trace_special       |  -12
  tracing_sched_wakeup_trace |   -8
 9 functions changed, 90 bytes removed, diff: -90

linux-2.6-tip/block/blktrace.c:
  __blk_add_trace |   -1
 1 function changed, 1 bytes removed, diff: -1

/tmp/vmlinux.after:
 10 functions changed, 91 bytes removed, diff: -91

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:40 +01:00
Steven Rostedt 5e4abc9839 trace: clean up format errors in calls to trace_seq_printf
After adding the printf format checking for trace_seq_printf, several
warnings now show up. This patch cleans them up.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-16 12:17:38 +01:00
Pekka Paalanen 173ed24ee2 mmiotrace: count events lost due to not recording
Impact: enhances lost events counting in mmiotrace

The tracing framework, or the ring buffer facility it uses, has a switch
to stop recording data. When recording is off, the trace events will be
lost. The framework does not count these, so mmiotrace has to count them
itself.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-11 04:01:30 +01:00
Steven Rostedt f0868d1e23 ftrace: set up trace event hash infrastructure
Impact: simplify/generalize/refactor trace.c

The trace.c file is becoming more difficult to maintain due to the
growing number of events. There is several formats that an event may
be printed. This patch sets up the infrastructure of an event hash to
allow for events to register how they should be printed.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-29 12:46:11 +01:00
Steven Rostedt c47956d9ae ftrace: remove obsolete print continue functionality
Impact: cleanup, remove obsolete code

Now that the ring buffer used by ftrace allows for variable length
entries, we do not need the 'cont' feature of the buffer.  This code
makes other parts of ftrace more complex and by removing this it
simplifies the ftrace code.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-29 12:46:10 +01:00
Pekka J Enberg 213cc06079 ftrace: introduce tracing_reset_online_cpus() helper
Impact: cleanup

This patch factors out common code from multiple tracers into a
tracing_reset_online_cpus() function and converts the tracers to use it.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-19 16:29:34 +01:00
Frederic Weisbecker 1fd8f2a3f9 tracing/function-graph-tracer: handle ftrace_printk entries
Handle the TRACE_PRINT entries from the function grapg tracer
and output them as a C comment just below the function that called
it, as if it was a comment inside this function.

Example with an ftrace_printk inside might_sleep() function:

void __might_sleep(char *file, int line)
{
	static unsigned long prev_jiffy;	/* ratelimiting */

	ftrace_printk("Hi I'm a comment in might_sleep() :-)");

A chunk of a resulting trace:

 0)               |        _reiserfs_free_block() {
 0)               |          reiserfs_read_bitmap_block() {
 0)               |            __bread() {
 0)               |              __getblk() {
 0)               |                __find_get_block() {
 0)   0.698 us    |                  mark_page_accessed();
 0)   2.267 us    |                }
 0)               |                __might_sleep() {
 0)               |                  /* Hi I'm a comment in might_sleep() :-) */
 0)   1.321 us    |                }
 0)   5.872 us    |              }
 0)   7.313 us    |            }
 0)   8.718 us    |          }

And this patch brings two minor fixes:

- The newline after a switch-out task has disappeared
- The "|" sign just before the cpu number on task-switch has been deleted.

 0)   0.616 us    |                pick_next_task_rt();
 0)   1.457 us    |                _spin_trylock();
 0)   0.653 us    |                _spin_unlock();
 0)   0.728 us    |                _spin_trylock();
 0)   0.631 us    |                _spin_unlock();
 0)   0.729 us    |                native_load_sp0();
 0)   0.593 us    |                native_load_tls();
 ------------------------------------------
 0)    cat-2834    =>   migrati-3
 ------------------------------------------

 0)               |    finish_task_switch() {
 0)   0.841 us    |      _spin_unlock_irq();
 0)   0.616 us    |      post_schedule_rt();
 0)   3.882 us    |    }

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04 10:18:39 +01:00
Ingo Molnar 6f893fb2e8 Merge branches 'tracing/branch-tracer', 'tracing/fastboot', 'tracing/ftrace', 'tracing/function-return-tracer', 'tracing/power-tracer', 'tracing/powerpc', 'tracing/ring-buffer', 'tracing/stack-tracer' and 'tracing/urgent' into tracing/core 2008-11-24 17:46:24 +01:00
Pekka Paalanen 7ee1768ddb x86, mmiotrace: fix buffer overrun detection
Impact: fix mmiotrace overrun tracing

When ftrace framework moved to use the ring buffer facility, the buffer
overrun detection was broken after 2.6.27 by commit

| commit 3928a8a2d9
| Author: Steven Rostedt <rostedt@goodmis.org>
| Date:   Mon Sep 29 23:02:41 2008 -0400
|
|     ftrace: make work with new ring buffer
|
|     This patch ports ftrace over to the new ring buffer.

The detection is now fixed by using the ring buffer API.

When mmiotrace detects a buffer overrun, it will report the number of
lost events. People reading an mmiotrace log must know if something was
missed, otherwise the data may not make sense.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 20:33:23 +01:00
Frederic Weisbecker 1c80025a49 tracing/ftrace: change the type of the init() callback
Impact: extend the ->init() method with the ability to fail

This bring a way to know if the initialization of a tracer successed.
A tracer must return 0 on success and a traditional error (ie:
-ENOMEM) if it fails.

If a tracer fails to init, it is free to print a detailed warn. The
tracing api will not and switch to a new tracer will just return the
error from the init callback.

Note: this will be used for the return tracer.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:55:23 +01:00
Steven Rostedt c76f06945b ftrace: remove trace array ctrl
Impact: remove obsolete variable in trace_array structure

With the new start / stop method of ftrace, the ctrl variable
in the trace_array structure is now obsolete. Remove it.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-08 09:51:39 +01:00
Steven Rostedt bbf5b1a0ce ftrace: remove ctrl_update method
Impact: Remove the ctrl_update tracer method

With the new quick start/stop method of tracing, the ctrl_update
method is out of date.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-08 09:51:34 +01:00
Steven Rostedt 38697053fa ftrace: preempt disable over interrupt disable
With the new ring buffer infrastructure in ftrace, I'm trying to make
ftrace a little more light weight.

This patch converts a lot of the local_irq_save/restore into
preempt_disable/enable.  The original preempt count in a lot of cases
has to be sent in as a parameter so that it can be recorded correctly.
Some places were recording it incorrectly before anyway.

This is also laying the ground work to make ftrace a little bit
more reentrant, and remove all locking. The function tracers must
still protect from reentrancy.

Note: All the function tracers must be careful when using preempt_disable.
  It must do the following:

  resched = need_resched();
  preempt_disable_notrace();
  [...]
  if (resched)
	preempt_enable_no_resched_notrace();
  else
	preempt_enable_notrace();

The reason is that if this function traces schedule() itself, the
preempt_enable_notrace() will cause a schedule, which will lead
us into a recursive failure.

If we needed to reschedule before calling preempt_disable, we
should have already scheduled. Since we did not, this is most
likely that we should not and are probably inside a schedule
function.

If resched was not set, we still need to catch the need resched
flag being set when preemption was off and the if case at the
end will catch that for us.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:09 +02:00
Steven Rostedt 7104f300c5 ftrace: type cast filter+verifier
The mmiotrace map had a bug that would typecast the entry from
the trace to the wrong type. That is a known danger of C typecasts,
there's absolutely zero checking done on them.

Help that problem a bit by using a GCC extension to implement a
type filter that restricts the types that a trace record can be
cast into, and by adding a dynamic check (in debug mode) to verify
the type of the entry.

This patch adds a macro to assign all entries of ftrace using the type
of the variable and checking the entry id. The typecasts are now done
in the macro for only those types that it knows about, which should
be all the types that are allowed to be read from the tracer.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:07 +02:00
Frederic Weisbecker 07f4e4f790 tracing/ftrace: adapt mmiotrace to the new type of print_line
Adapt mmiotrace to the new print_line type.
By default, it ignores (and consumes) types it doesn't support.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:02 +02:00
Steven Rostedt 777e208d40 ftrace: take advantage of variable length entries
Now that the underlining ring buffer for ftrace now hold variable length
entries, we can take advantage of this by only storing the size of the
actual event into the buffer. This happens to increase the number of
entries in the buffer dramatically.

We can also get rid of the "trace_cont" operation, but I'm keeping that
until we have no more users. Some of the ftrace tracers can now change
their code to adapt to this new feature.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:59 +02:00
Steven Rostedt 3928a8a2d9 ftrace: make work with new ring buffer
This patch ports ftrace over to the new ring buffer.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:57 +02:00
Pekka Paalanen fc5e27ae4b mmiotrace: handle TRACE_PRINT entries
Also make trace_seq_print_cont() non-static, and add a newline if the
seq buffer can't hold all data.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:14 +02:00
Pekka Paalanen 9e57fb35d7 x86 mmiotrace: implement mmiotrace_printk()
Offer mmiotrace users a function to inject markers from inside the kernel.
This depends on the trace_vprintk() patch.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:11 +02:00
Pekka Paalanen 45dcd8b8a8 ftrace: move mmiotrace functions out of trace.c
Moves the mmiotrace specific functions from trace.c to
trace_mmiotrace.c. Functions trace_wake_up(), tracing_get_trace_entry(),
and tracing_generic_entry_update() are therefore made available outside
trace.c.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:04 +02:00
Steven Rostedt 2e2ca155cd ftrace: new continue entry - separate out from trace_entry
Some tracers will need to work with more than one entry. In order to do this
the trace_entry structure was split into two fields. One for the start of
all entries, and one to continue an existing entry.

The trace_entry structure now has a "field" entry that consists of the previous
content of the trace_entry, and a "cont" entry that is just a string buffer
the size of the "field" entry.

Thanks to Andrew Morton for suggesting this idea.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:35:15 +02:00
Pekka Paalanen dee310d0ad x86 mmiotrace: use resource_size_t for phys addresses
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-24 11:27:36 +02:00
Pekka Paalanen e0fd5c2fa1 mmiotrace: do not print bogus pid for maps either
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-24 11:27:15 +02:00
Pekka Paalanen 2039238b79 mmiotrace: print overrun counts
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-24 11:27:08 +02:00
Pekka Paalanen d0a7e8ca5b mmiotrace: print header using the read hook.
Now the header is printed only for `trace_pipe' file.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-24 11:27:03 +02:00
Pekka Paalanen 736ca61fa8 x86 mmiotrace: Do not print bogus pid
Non-zero pid indicates the MMIO access originated in user space.
We do not catch that kind of accesses yet, so always print zero for now.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 11:26:00 +02:00
Pekka Paalanen 138295373c ftrace: mmiotrace update, #2
another weekend, another patch. This should apply on top of my previous patch
from March 23rd.

Summary of changes:
- Print PCI device list in output header
- work around recursive probe hits on SMP
- refactor dis/arm_kmmio_fault_page() and add check for page levels
- remove un/reference_kmmio(), the die notifier hook is registered
permanently into the list
- explicitly check for single stepping in die notifier callback

I have tested this version on my UP Athlon64 desktop with Nouveau, and
SMP Core 2 Duo laptop with the proprietary nvidia driver. Both systems
are 64-bit. One previously unknown bug crept into daylight: the ftrace
framework's output routines print the first entry last after buffer has
wrapped around.

The most important regressions compared to non-ftrace mmiotrace at this
time are:
- failure of trace_pipe file
- illegal lines in output file
- unaware of losing data due to buffer full

Personally I'd like to see these three solved before submitting to
mainline. Other issues may come up once we know when we lose events.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 11:25:16 +02:00
Pekka Paalanen bd8ac686c7 ftrace: mmiotrace, updates
here is a patch that makes mmiotrace work almost well within the tracing
framework. The patch applies on top of my previous patch. I have my own
output formatting in place now.

Summary of changes:
- fix the NULL dereference that was due to not calling tracing_reset()
- add print_line() callback into struct tracer
- implement print_line() for mmiotrace, producing up-to-spec text
- add my output header, but that is not really called in the right place
- rewrote the main structs in mmiotrace
- added two new trace entry types: TRACE_MMIO_RW and TRACE_MMIO_MAP
- made some functions in trace.c non-static
- check current==NULL in tracing_generic_entry_update()
- fix(?) comparison in trace_seq_printf()

Things seem to work fine except a few issues. Markers (text lines injected
into mmiotrace log) are missing, I did not feel hacking them in before we
have variable length entries. My output header is printed only for 'trace'
file, but not 'trace_pipe'. For some reason, despite my quick fix,
iter->trace is NULL in print_trace_line() when called from 'trace_pipe'
file, which means I don't get proper output formatting.

I only tried by loading nouveau.ko, which just detects the card, and that
is traced fine. I didn't try further. Map, two reads and unmap. Works
perfectly.

I am missing the information about overflows, I'd prefer to have a
counter for lost events. I didn't try, but I guess currently there is no
way of knowning when it overflows?

So, not too far from being fully operational, it seems :-)
And looking at the diffstat, there also is some 700-900 lines of user space
code that just became obsolete.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 11:24:53 +02:00
Pekka Paalanen f984b51e07 ftrace: add mmiotrace plugin
On Sat, 22 Mar 2008 13:07:47 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> > > i'd suggest the following: pull x86.git and sched-devel.git into a
> > > single tree [the two will combine without rejects]. Then try to add a
> > > kernel/tracing/trace_mmiotrace.c ftrace plugin. The trace_sysprof.c
> > > plugin might be a good example.
> >
> > I did this and now I have mmiotrace enabled/disabled via the tracing
> > framework (what do we call this, since ftrace is one of the tracers?).
>
> cool! could you send the patches for that? (even if they are not fully
> functional yet)

Patch attached in the end. Nice to see how much code disappeared. I tried
to mark all the features I had to break with XXX-comments.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 11:22:43 +02:00