From patchwork Thu Jul 3 16:26:08 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Morten Rasmussen X-Patchwork-Id: 4476091 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id ACD8ABEEAA for ; Thu, 3 Jul 2014 16:26:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C5E94201FB for ; Thu, 3 Jul 2014 16:26:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B1DA203E1 for ; Thu, 3 Jul 2014 16:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759369AbaGCQ01 (ORCPT ); Thu, 3 Jul 2014 12:26:27 -0400 Received: from service87.mimecast.com ([91.220.42.44]:45939 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759365AbaGCQ0Z (ORCPT ); Thu, 3 Jul 2014 12:26:25 -0400 Received: from cam-owa2.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Thu, 03 Jul 2014 17:26:23 +0100 Received: from e103034-lin.cambridge.arm.com ([10.1.255.212]) by cam-owa2.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.3959); Thu, 3 Jul 2014 17:26:23 +0100 From: Morten Rasmussen To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, peterz@infradead.org, mingo@kernel.org Cc: rjw@rjwysocki.net, vincent.guittot@linaro.org, daniel.lezcano@linaro.org, preeti@linux.vnet.ibm.com, Dietmar.Eggemann@arm.com, pjt@google.com Subject: [RFCv2 PATCH 21/23] sched: Use energy model in select_idle_sibling Date: Thu, 3 Jul 2014 17:26:08 +0100 Message-Id: <1404404770-323-22-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1404404770-323-1-git-send-email-morten.rasmussen@arm.com> References: <1404404770-323-1-git-send-email-morten.rasmussen@arm.com> X-OriginalArrivalTime: 03 Jul 2014 16:26:23.0850 (UTC) FILETIME=[87DDD4A0:01CF96DB] X-MC-Unique: 114070317262314501 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Make select_idle_sibling() consider energy when picking an idle cpu. This implies having to look beyond sd_llc. Otherwise, consolidating short frequently running tasks on fewer llc domains will not happen when that is feasible. The fix is to start select_idle_sibling() at the highest sched_domain level. A more refined approach causing less overhead will be considered later. That could be to only look beyond sd_llc occasionally. Only idle cpus are still considered. A more aggressive energy conserving approach could go further and consider partially utilized cpus. Signed-off-by: Morten Rasmussen --- kernel/sched/fair.c | 41 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 37 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index aebf3e2..a32d6eb 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4747,9 +4747,19 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) */ static int select_idle_sibling(struct task_struct *p, int target) { - struct sched_domain *sd; + struct sched_domain *sd = NULL, *tmp; struct sched_group *sg; int i = task_cpu(p); + int target_nrg; + int nrg_min, nrg_cpu = -1; + + if (energy_aware()) { + /* When energy-aware, go above sd_llc */ + for_each_domain(target, tmp) + sd = tmp; + + goto loop; + } if (idle_cpu(target)) return target; @@ -4764,6 +4774,10 @@ static int select_idle_sibling(struct task_struct *p, int target) * Otherwise, iterate the domains and find an elegible idle cpu. */ sd = rcu_dereference(per_cpu(sd_llc, target)); + +loop: + target_nrg = nrg_min = energy_diff_task(target, p); + for_each_lower_domain(sd) { sg = sd->groups; do { @@ -4772,16 +4786,35 @@ static int select_idle_sibling(struct task_struct *p, int target) goto next; for_each_cpu(i, sched_group_cpus(sg)) { + int nrg_diff; + if (energy_aware()) { + if (!idle_cpu(i)) + continue; + + nrg_diff = energy_diff_task(i, p); + if (nrg_diff < nrg_min) { + nrg_min = nrg_diff; + nrg_cpu = i; + } + } + if (i == target || !idle_cpu(i)) goto next; } - target = cpumask_first_and(sched_group_cpus(sg), - tsk_cpus_allowed(p)); - goto done; + if (!energy_aware()) { + target = cpumask_first_and(sched_group_cpus(sg), + tsk_cpus_allowed(p)); + goto done; + } next: sg = sg->next; } while (sg != sd->groups); + + if (nrg_cpu >= 0) { + target = nrg_cpu; + goto done; + } } done: return target;