From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755261AbZKUNnY (ORCPT ); Sat, 21 Nov 2009 08:43:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754740AbZKUNnX (ORCPT ); Sat, 21 Nov 2009 08:43:23 -0500 Received: from hera.kernel.org ([140.211.167.34]:60934 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754690AbZKUNnS (ORCPT ); Sat, 21 Nov 2009 08:43:18 -0500 Date: Sat, 21 Nov 2009 13:42:37 GMT From: tip-bot for Peter Zijlstra Cc: linux-kernel@vger.kernel.org, paulus@samba.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20091120212508.779516394@chello.nl> References: <20091120212508.779516394@chello.nl> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf: Optimize perf_event_task_sched_out Message-ID: Git-Commit-ID: 02ffdbc866c8b1c8644601e9aa6155700eed4c91 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 02ffdbc866c8b1c8644601e9aa6155700eed4c91 Gitweb: http://git.kernel.org/tip/02ffdbc866c8b1c8644601e9aa6155700eed4c91 Author: Peter Zijlstra AuthorDate: Fri, 20 Nov 2009 22:19:50 +0100 Committer: Ingo Molnar CommitDate: Sat, 21 Nov 2009 14:11:38 +0100 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 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 9a18ff2..65f4dab 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;