From 02ffdbc866c8b1c8644601e9aa6155700eed4c91 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 20 Nov 2009 22:19:50 +0100 Subject: [PATCH] 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 Cc: Paul Mackerras LKML-Reference: <20091120212508.779516394@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 4 ++-- 1 file 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; -- 2.20.1