linux/include/trace/events/irq.h

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#undef TRACE_SYSTEM
#define TRACE_SYSTEM irq
#if !defined(_TRACE_IRQ_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_IRQ_H
#include <linux/tracepoint.h>
struct irqaction;
struct softirq_action;
#define softirq_name(sirq) { sirq##_SOFTIRQ, #sirq }
#define show_softirq_name(val) \
__print_symbolic(val, \
softirq_name(HI), \
softirq_name(TIMER), \
softirq_name(NET_TX), \
softirq_name(NET_RX), \
softirq_name(BLOCK), \
softirq_name(BLOCK_IOPOLL), \
softirq_name(TASKLET), \
softirq_name(SCHED), \
rcu: Use softirq to address performance regression Commit a26ac2455ffcf3(rcu: move TREE_RCU from softirq to kthread) introduced performance regression. In an AIM7 test, this commit degraded performance by about 40%. The commit runs rcu callbacks in a kthread instead of softirq. We observed high rate of context switch which is caused by this. Out test system has 64 CPUs and HZ is 1000, so we saw more than 64k context switch per second which is caused by RCU's per-CPU kthread. A trace showed that most of the time the RCU per-CPU kthread doesn't actually handle any callbacks, but instead just does a very small amount of work handling grace periods. This means that RCU's per-CPU kthreads are making the scheduler do quite a bit of work in order to allow a very small amount of RCU-related processing to be done. Alex Shi's analysis determined that this slowdown is due to lock contention within the scheduler. Unfortunately, as Peter Zijlstra points out, the scheduler's real-time semantics require global action, which means that this contention is inherent in real-time scheduling. (Yes, perhaps someone will come up with a workaround -- otherwise, -rt is not going to do well on large SMP systems -- but this patch will work around this issue in the meantime. And "the meantime" might well be forever.) This patch therefore re-introduces softirq processing to RCU, but only for core RCU work. RCU callbacks are still executed in kthread context, so that only a small amount of RCU work runs in softirq context in the common case. This should minimize ksoftirqd execution, allowing us to skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Tested-by: "Alex,Shi" <alex.shi@intel.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-06-14 07:26:25 +02:00
softirq_name(HRTIMER), \
softirq_name(RCU))
/**
* irq_handler_entry - called immediately before the irq action handler
* @irq: irq number
* @action: pointer to struct irqaction
*
* The struct irqaction pointed to by @action contains various
* information about the handler, including the device name,
* @action->name, and the device id, @action->dev_id. When used in
* conjunction with the irq_handler_exit tracepoint, we can figure
* out irq handler latencies.
*/
TRACE_EVENT(irq_handler_entry,
TP_PROTO(int irq, struct irqaction *action),
TP_ARGS(irq, action),
TP_STRUCT__entry(
__field( int, irq )
__string( name, action->name )
),
TP_fast_assign(
__entry->irq = irq;
__assign_str(name, action->name);
),
events: Harmonize event field names and print output names Now that we can filter based on fields via perf record, people will start using filter expressions and will expect them to be obvious. The primary way to see which fields are available is by looking at the trace output, such as: gcc-18676 [000] 343.011728: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.012727: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.032692: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.033690: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.034687: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.035686: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.036684: irq_handler_entry: irq=0 handler=timer While 'irq==0' filters work, the 'handler==<x>' filter expression does not work: $ perf record -R -f -a -e irq:irq_handler_entry --filter handler=timer sleep 1 Error: failed to set filter with 22 (Invalid argument) The problem is that while an 'irq' field exists and is recognized as a filter field - 'handler' does not exist - its name is 'name' in the output. To solve this, we need to synchronize the printout and the field names, wherever possible. In cases where the printout prints a non-field, we enclose that information in square brackets, such as: perf-1380 [013] 724.903505: softirq_exit: vec=9 [action=RCU] perf-1380 [013] 724.904482: softirq_exit: vec=1 [action=TIMER] This way users can use filter expressions more intuitively: all fields that show up as 'primary' (non-bracketed) information is filterable. This patch harmonizes the field names for all irq, bkl, power, sched and timer events. We might in fact think about dropping the print format bit of generic tracepoints altogether, and just print the fields that are being recorded. Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-15 11:50:39 +02:00
TP_printk("irq=%d name=%s", __entry->irq, __get_str(name))
);
/**
* irq_handler_exit - called immediately after the irq action handler returns
* @irq: irq number
* @action: pointer to struct irqaction
* @ret: return value
*
* If the @ret value is set to IRQ_HANDLED, then we know that the corresponding
* @action->handler scuccessully handled this irq. Otherwise, the irq might be
* a shared irq line, or the irq was not handled successfully. Can be used in
* conjunction with the irq_handler_entry to understand irq handler latencies.
*/
TRACE_EVENT(irq_handler_exit,
TP_PROTO(int irq, struct irqaction *action, int ret),
TP_ARGS(irq, action, ret),
TP_STRUCT__entry(
__field( int, irq )
__field( int, ret )
),
TP_fast_assign(
__entry->irq = irq;
__entry->ret = ret;
),
events: Harmonize event field names and print output names Now that we can filter based on fields via perf record, people will start using filter expressions and will expect them to be obvious. The primary way to see which fields are available is by looking at the trace output, such as: gcc-18676 [000] 343.011728: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.012727: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.032692: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.033690: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.034687: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.035686: irq_handler_entry: irq=0 handler=timer cc1-18677 [000] 343.036684: irq_handler_entry: irq=0 handler=timer While 'irq==0' filters work, the 'handler==<x>' filter expression does not work: $ perf record -R -f -a -e irq:irq_handler_entry --filter handler=timer sleep 1 Error: failed to set filter with 22 (Invalid argument) The problem is that while an 'irq' field exists and is recognized as a filter field - 'handler' does not exist - its name is 'name' in the output. To solve this, we need to synchronize the printout and the field names, wherever possible. In cases where the printout prints a non-field, we enclose that information in square brackets, such as: perf-1380 [013] 724.903505: softirq_exit: vec=9 [action=RCU] perf-1380 [013] 724.904482: softirq_exit: vec=1 [action=TIMER] This way users can use filter expressions more intuitively: all fields that show up as 'primary' (non-bracketed) information is filterable. This patch harmonizes the field names for all irq, bkl, power, sched and timer events. We might in fact think about dropping the print format bit of generic tracepoints altogether, and just print the fields that are being recorded. Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-15 11:50:39 +02:00
TP_printk("irq=%d ret=%s",
__entry->irq, __entry->ret ? "handled" : "unhandled")
);
DECLARE_EVENT_CLASS(softirq,
TP_PROTO(unsigned int vec_nr),
TP_ARGS(vec_nr),
TP_STRUCT__entry(
__field( unsigned int, vec )
),
TP_fast_assign(
__entry->vec = vec_nr;
),
TP_printk("vec=%u [action=%s]", __entry->vec,
show_softirq_name(__entry->vec))
);
/**
* softirq_entry - called immediately before the softirq handler
* @vec_nr: softirq vector number
*
* When used in combination with the softirq_exit tracepoint
* we can determine the softirq handler runtine.
*/
DEFINE_EVENT(softirq, softirq_entry,
TP_PROTO(unsigned int vec_nr),
TP_ARGS(vec_nr)
);
/**
* softirq_exit - called immediately after the softirq handler returns
* @vec_nr: softirq vector number
*
* When used in combination with the softirq_entry tracepoint
* we can determine the softirq handler runtine.
*/
DEFINE_EVENT(softirq, softirq_exit,
TP_PROTO(unsigned int vec_nr),
TP_ARGS(vec_nr)
);
/**
* softirq_raise - called immediately when a softirq is raised
* @vec_nr: softirq vector number
*
* When used in combination with the softirq_entry tracepoint
* we can determine the softirq raise to run latency.
*/
DEFINE_EVENT(softirq, softirq_raise,
TP_PROTO(unsigned int vec_nr),
TP_ARGS(vec_nr)
);
tracing: create automated trace defines This patch lowers the number of places a developer must modify to add new tracepoints. The current method to add a new tracepoint into an existing system is to write the trace point macro in the trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or DECLARE_TRACE, then they must add the same named item into the C file with the macro DEFINE_TRACE(name) and then add the trace point. This change cuts out the needing to add the DEFINE_TRACE(name). Every file that uses the tracepoint must still include the trace/<type>.h file, but the one C file must also add a define before the including of that file. #define CREATE_TRACE_POINTS #include <trace/mytrace.h> This will cause the trace/mytrace.h file to also produce the C code necessary to implement the trace point. Note, if more than one trace/<type>.h is used to create the C code it is best to list them all together. #define CREATE_TRACE_POINTS #include <trace/foo.h> #include <trace/bar.h> #include <trace/fido.h> Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with the cleaner solution of the define above the includes over my first design to have the C code include a "special" header. This patch converts sched, irq and lockdep and skb to use this new method. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-10 15:36:00 +02:00
#endif /* _TRACE_IRQ_H */
/* This part must be outside protection */
#include <trace/define_trace.h>