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[209.132.180.67]) by mx.google.com with ESMTP id dv5si3838559pbb.283.2014.01.15.06.24.21; Wed, 15 Jan 2014 06:24:21 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752111AbaAOOYP (ORCPT + 26 others); Wed, 15 Jan 2014 09:24:15 -0500 Received: from mail-pd0-f178.google.com ([209.85.192.178]:34625 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751735AbaAOOYN (ORCPT ); Wed, 15 Jan 2014 09:24:13 -0500 Received: by mail-pd0-f178.google.com with SMTP id y13so1177274pdi.9 for ; Wed, 15 Jan 2014 06:24:13 -0800 (PST) X-Received: by 10.66.179.143 with SMTP id dg15mr3191340pac.52.1389795853457; Wed, 15 Jan 2014 06:24:13 -0800 (PST) Received: from alex-shi.Home ([162.243.130.63]) by mx.google.com with ESMTPSA id ki1sm8480409pbd.1.2014.01.15.06.23.55 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 15 Jan 2014 06:24:12 -0800 (PST) From: Alex Shi To: mingo@redhat.com, peterz@infradead.org, morten.rasmussen@arm.com, vincent.guittot@linaro.org, daniel.lezcano@linaro.org Cc: wangyun@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, Alex Shi Subject: [RFC PATCH] sched: select_idle_sibling macro optimize Date: Wed, 15 Jan 2014 22:23:28 +0800 Message-Id: <1389795808-32013-1-git-send-email-alex.shi@linaro.org> X-Mailer: git-send-email 1.8.1.2 Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: alex.shi@linaro.org X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 209.85.128.182 is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , 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; + do { if (!cpumask_intersects(sched_group_cpus(sg), tsk_cpus_allowed(p)))