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perf: Optimize perf_event_task_sched_out

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Remove an update_context_time() call from the
perf_event_task_sched_out() path and into the branch its needed.

The call was both superfluous, because __perf_event_sched_out()
already does it, and wrong, because it was done without holding
ctx->lock.

Place it in perf_event_sync_stat(), which is the only place it
is needed and which does already hold ctx->lock.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.779516394@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-11-20 22:19:50 +01:00 committed by Ingo Molnar
parent abf4868b85
commit 02ffdbc866
1 changed files with 2 additions and 2 deletions
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4
kernel/perf_event.c
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@ -1120,6 +1120,8 @@ static void perf_event_sync_stat(struct perf_event_context *ctx,
if (!ctx->nr_stat)
return;
update_context_time(ctx);
event = list_first_entry(&ctx->event_list,
struct perf_event, event_entry);
@ -1163,8 +1165,6 @@ void perf_event_task_sched_out(struct task_struct *task,
if (likely(!ctx || !cpuctx->task_ctx))
return;
update_context_time(ctx);
rcu_read_lock();
parent = rcu_dereference(ctx->parent_ctx);
next_ctx = next->perf_event_ctxp;