Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752674AbaAPNwV (ORCPT ); Thu, 16 Jan 2014 08:52:21 -0500 Received: from mout.gmx.net ([212.227.17.20]:58480 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752513AbaAPNwU (ORCPT ); Thu, 16 Jan 2014 08:52:20 -0500 Message-ID: <1389880335.5418.46.camel@marge.simpson.net> Subject: Re: [RFC PATCH] sched: select_idle_sibling macro optimize From: Mike Galbraith To: Alex Shi Cc: mingo@redhat.com, peterz@infradead.org, morten.rasmussen@arm.com, vincent.guittot@linaro.org, daniel.lezcano@linaro.org, wangyun@linux.vnet.ibm.com, linux-kernel@vger.kernel.org Date: Thu, 16 Jan 2014 14:52:15 +0100 In-Reply-To: <52D7DAF5.4020506@linaro.org> References: <1389795808-32013-1-git-send-email-alex.shi@linaro.org> <52D7DAF5.4020506@linaro.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Provags-ID: V03:K0:ZdaO/pMVrSukLMwLbp+pA15I9OONjKUuKXMlwMYEgEfKGWoJxSH 4msAQHLL/IUS/8+oypv1rL+YzkZgcp0Se3f42hb2GLlDqt6zKePqkgUaatMCjrXDhZBl9fK z4jKt0Z2MCEnBoLoEDPgTBBp4dPK3ArR0ap7sobFZQ2P1V0/nvbK+ZYqNBDRuNjYvEdnEBx WttlspDHWTUg5FAZxNZGg== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-01-16 at 21:13 +0800, Alex Shi wrote: > Add Mike Galbraith. > > Any one like to give some comments? > > On 01/15/2014 10:23 PM, Alex Shi wrote: > > If the sd domain just has one group, then we must be caught the > > i == target later, and then goes to deeper level domain. > > So just skip this domain checking to save some instructions. > > > > Signed-off-by: Alex Shi > > --- > > kernel/sched/fair.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index c7395d9..3265fbc 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -4196,6 +4196,11 @@ static int select_idle_sibling(struct task_struct *p, int target) > > sd = rcu_dereference(per_cpu(sd_llc, target)); > > for_each_lower_domain(sd) { > > sg = sd->groups; > > + > > + /* skip single group domain */ > > + if (sg == sg->next) > > + continue; When is that gonna happen? -Mike -- 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/