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sched: Deliver sched_switch events to the current task

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Otherwise they can't be filtered for a defined task:

  perf record -e sched:sched_switch ./foo

This command doesn't report any events without this patch.

I think it isn't a security concern if someone knows who will
be executed next - this can already be observed by polling /proc
state. By default perf is disabled for non-root users in any case.

I need these events for profiling sleep times.  sched_switch is used for
getting callchains and sched_stat_* is used for getting time periods.
These events are combined in user space, then it can be analyzed by
perf tools.

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arun Sharma <asharma@fb.com>
Link: http://lkml.kernel.org/r/1342088069-1005148-1-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andrew Vagin
2012-07-12 14:14:29 +04:00
committed by Ingo Molnar
parent 045e7e6047
commit 895dd92c03
1 changed files with 1 additions and 1 deletions
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2
kernel/sched/core.c
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@@ -1910,12 +1910,12 @@ static inline void
prepare_task_switch(struct rq *rq, struct task_struct *prev, prepare_task_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next) struct task_struct *next)
{ {
trace_sched_switch(prev, next);
sched_info_switch(prev, next); sched_info_switch(prev, next);
perf_event_task_sched_out(prev, next); perf_event_task_sched_out(prev, next);
fire_sched_out_preempt_notifiers(prev, next); fire_sched_out_preempt_notifiers(prev, next);
prepare_lock_switch(rq, next); prepare_lock_switch(rq, next);
prepare_arch_switch(next); prepare_arch_switch(next);
trace_sched_switch(prev, next);
} }
/** /**