Otherwise they can't be filtered for a defined task.
perf record -e sched:sched_switch ./foo
This command doesn't report any event without this patch.
I think it isn't a big problem for security, if someone will know
who will be executed next. By default perf is disabled for non-root
users.
I need this events for profiling sleep times. sched_switch is used for
getting callchains and sched_stat_* is used for getting time periods.
This events are combined in user space, then it can be analized by
perf tools.
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Arun Sharma <asha...@fb.com>
Signed-off-by: Andrew Vagin <ava...@openvz.org>
---
kernel/sched/core.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d5594a4..c5d6a0f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1910,12 +1910,12 @@ static inline void
prepare_task_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
+ trace_sched_switch(prev, next);
sched_info_switch(prev, next);
perf_event_task_sched_out(prev, next);
fire_sched_out_preempt_notifiers(prev, next);
prepare_lock_switch(rq, next);
prepare_arch_switch(next);
- trace_sched_switch(prev, next);
}
/**
--
1.7.1
--
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