From patchwork Tue May 12 19:39:07 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Morten Rasmussen X-Patchwork-Id: 6390721 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id D46B89F32E for ; Tue, 12 May 2015 19:40:30 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1B5A420373 for ; Tue, 12 May 2015 19:40:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34999202D1 for ; Tue, 12 May 2015 19:40:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933325AbbELTkJ (ORCPT ); Tue, 12 May 2015 15:40:09 -0400 Received: from foss.arm.com ([217.140.101.70]:34048 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964799AbbELTjJ (ORCPT ); Tue, 12 May 2015 15:39:09 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C841A29; Tue, 12 May 2015 12:38:31 -0700 (PDT) Received: from e105550-lin.cambridge.arm.com (e105550-lin.cambridge.arm.com [10.2.131.193]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 689533F218; Tue, 12 May 2015 12:39:06 -0700 (PDT) From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: vincent.guittot@linaro.org, Dietmar Eggemann , yuyang.du@intel.com, preeti@linux.vnet.ibm.com, mturquette@linaro.org, rjw@rjwysocki.net, Juri Lelli , sgurrappadi@nvidia.com, pang.xunlei@zte.com.cn, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, morten.rasmussen@arm.com Subject: [RFCv4 PATCH 32/34] sched: Consider a not over-utilized energy-aware system as balanced Date: Tue, 12 May 2015 20:39:07 +0100 Message-Id: <1431459549-18343-33-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1431459549-18343-1-git-send-email-morten.rasmussen@arm.com> References: <1431459549-18343-1-git-send-email-morten.rasmussen@arm.com> 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 From: Dietmar Eggemann In case the system operates below the tipping point indicator, introduced in ("sched: Add over-utilization/tipping point indicator"), bail out in find_busiest_group after the dst and src group statistics have been checked. There is simply no need to move usage around because all involved cpus still have spare cycles available. For an energy-aware system below its tipping point, we rely on the task placement of the wakeup path. This works well for short running tasks. The existence of long running tasks on one of the involved cpus lets the system operate over its tipping point. To be able to move such a task (whose load can't be used to average the load among the cpus) from a src cpu with lower capacity than the dst_cpu, an additional rule has to be implemented in need_active_balance. Signed-off-by: Dietmar Eggemann --- kernel/sched/fair.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index fe41e1e..83218e0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7340,6 +7340,10 @@ static struct sched_group *find_busiest_group(struct lb_env *env) * this level. */ update_sd_lb_stats(env, &sds); + + if (energy_aware() && !env->dst_rq->rd->overutilized) + goto out_balanced; + local = &sds.local_stat; busiest = &sds.busiest_stat;