From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752159AbaJ0IFb (ORCPT ); Mon, 27 Oct 2014 04:05:31 -0400 Received: from e23smtp01.au.ibm.com ([202.81.31.143]:34105 "EHLO e23smtp01.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751024AbaJ0IF3 (ORCPT ); Mon, 27 Oct 2014 04:05:29 -0400 Date: Mon, 27 Oct 2014 13:34:22 +0530 From: Srikar Dronamraju To: Yao Dongdong Cc: Ingo Molnar , Peter Zijlstra , LKML Subject: Re: [PATCH] sched:skip loop non-idle cpus after find an idle cpu while find_idlest_cpu Message-ID: <20141027080422.GB10867@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <544DB84D.1030504@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <544DB84D.1030504@huawei.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14102708-1618-0000-0000-00000124EF8D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Yao Dongdong [2014-10-27 11:13:17]: > Idle cpu is idler than non-idle cpu, so we needn't loop non-idle cpus after find an idle cpu. > While this check looks good, I dont see how we are avoiding a loop? Are you suggesting that we break of the for loop once we set shallowest_idle_cpu? -- Thanks and Regards Srikar > Signed-off-by:yaodongdong@huawei.com > > --- > kernel/sched/fair.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 0b069bf..2445a23 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4446,7 +4446,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) > latest_idle_timestamp = rq->idle_stamp; > shallowest_idle_cpu = i; > } > - } else { > + } else if (shallowest_idle_cpu == -1) { > load = weighted_cpuload(i); > if (load < min_load || (load == min_load && i == this_cpu)) { > min_load = load; > -- > 1.8.0.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Thanks and Regards Srikar Dronamraju