From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932958Ab0CKOnj (ORCPT ); Thu, 11 Mar 2010 09:43:39 -0500 Received: from hera.kernel.org ([140.211.167.34]:43453 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932608Ab0CKOna (ORCPT ); Thu, 11 Mar 2010 09:43:30 -0500 Date: Thu, 11 Mar 2010 14:42:23 GMT From: "tip-bot for eranian@google.com" Cc: linux-kernel@vger.kernel.org, eranian@google.com, 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, eranian@google.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1268288765-5326-1-git-send-email-eranian@google.com> References: <1268288765-5326-1-git-send-email-eranian@google.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf_events: Improve task_sched_in() Message-ID: Git-Commit-ID: 9b33fa6ba0e2f90fdf407501db801c2511121564 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Thu, 11 Mar 2010 14:42:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 9b33fa6ba0e2f90fdf407501db801c2511121564 Gitweb: http://git.kernel.org/tip/9b33fa6ba0e2f90fdf407501db801c2511121564 Author: eranian@google.com AuthorDate: Wed, 10 Mar 2010 22:26:05 -0800 Committer: Ingo Molnar CommitDate: Thu, 11 Mar 2010 15:23:28 +0100 perf_events: Improve task_sched_in() This patch is an optimization in perf_event_task_sched_in() to avoid scheduling the events twice in a row. Without it, the perf_disable()/perf_enable() pair is invoked twice, thereby pinned events counts while scheduling flexible events and we go throuh hw_perf_enable() twice. By encapsulating, the whole sequence into perf_disable()/perf_enable() we ensure, hw_perf_enable() is going to be invoked only once because of the refcount protection. Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra LKML-Reference: <1268288765-5326-1-git-send-email-eranian@google.com> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 52c69a3..3853d49 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1368,6 +1368,8 @@ void perf_event_task_sched_in(struct task_struct *task) if (cpuctx->task_ctx == ctx) return; + perf_disable(); + /* * We want to keep the following priority order: * cpu pinned (that don't need to move), task pinned, @@ -1380,6 +1382,8 @@ void perf_event_task_sched_in(struct task_struct *task) ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE); cpuctx->task_ctx = ctx; + + perf_enable(); } #define MAX_INTERRUPTS (~0ULL)