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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-11-20 22:19:50 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-11-21 14:11:38 +0100 |
| commit | 02ffdbc866c8b1c8644601e9aa6155700eed4c91 (patch) | |
| tree | fd5c0cfbbadc22e123aa25c17c74ac69f8b14887 /kernel/perf_event.c | |
| parent | abf4868b8548cae18d4fe8bbfb4e207443be01be (diff) | |
| download | lwn-02ffdbc866c8b1c8644601e9aa6155700eed4c91.tar.gz lwn-02ffdbc866c8b1c8644601e9aa6155700eed4c91.zip | |
perf: Optimize perf_event_task_sched_out
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>
Diffstat (limited to 'kernel/perf_event.c')
| -rw-r--r-- | kernel/perf_event.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 9a18ff28ea5b..65f4dab0ce60 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -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; |