From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933131Ab1LFJvm (ORCPT ); Tue, 6 Dec 2011 04:51:42 -0500 Received: from terminus.zytor.com ([198.137.202.10]:34914 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933063Ab1LFJvl (ORCPT ); Tue, 6 Dec 2011 04:51:41 -0500 Date: Tue, 6 Dec 2011 01:51:09 -0800 From: tip-bot for Mike Galbraith Message-ID: Cc: linux-kernel@vger.kernel.org, mgalbraith@suse.de, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, mgalbraith@suse.de, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1321971686.6855.18.camel@marge.simson.net> References: <1321971686.6855.18.camel@marge.simson.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched: Set skip_clock_update in yield_task_fair() Git-Commit-ID: 916671c08b7808aebec87cc56c85788e665b3c6b X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Tue, 06 Dec 2011 01:51:15 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 916671c08b7808aebec87cc56c85788e665b3c6b Gitweb: http://git.kernel.org/tip/916671c08b7808aebec87cc56c85788e665b3c6b Author: Mike Galbraith AuthorDate: Tue, 22 Nov 2011 15:21:26 +0100 Committer: Ingo Molnar CommitDate: Tue, 6 Dec 2011 09:06:24 +0100 sched: Set skip_clock_update in yield_task_fair() This is another case where we are on our way to schedule(), so can save a useless clock update and resulting microscopic vruntime update. Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1321971686.6855.18.camel@marge.simson.net Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 7 +++++++ kernel/sched/fair.c | 6 ++++++ 2 files changed, 13 insertions(+), 0 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ca8fd44..db313c3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4547,6 +4547,13 @@ again: */ if (preempt && rq != p_rq) resched_task(p_rq->curr); + } else { + /* + * We might have set it in task_yield_fair(), but are + * not going to schedule(), so don't want to skip + * the next update. + */ + rq->skip_clock_update = 0; } out: diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8e534a0..81ccb81 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3075,6 +3075,12 @@ static void yield_task_fair(struct rq *rq) * Update run-time statistics of the 'current'. */ update_curr(cfs_rq); + /* + * Tell update_rq_clock() that we've just updated, + * so we don't do microscopic update in schedule() + * and double the fastpath cost. + */ + rq->skip_clock_update = 1; } set_skip_buddy(se);