From patchwork Tue Jul 7 18:24:18 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Morten Rasmussen X-Patchwork-Id: 6738281 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 [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id DEB09C05AC for ; Tue, 7 Jul 2015 18:58:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1BBA720751 for ; Tue, 7 Jul 2015 18:58:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8E8C20727 for ; Tue, 7 Jul 2015 18:58:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932947AbbGGSXd (ORCPT ); Tue, 7 Jul 2015 14:23:33 -0400 Received: from foss.arm.com ([217.140.101.70]:37658 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932617AbbGGSXa (ORCPT ); Tue, 7 Jul 2015 14:23:30 -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 94A3A5E4; Tue, 7 Jul 2015 11:23:56 -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 76DA23F23A; Tue, 7 Jul 2015 11:23:27 -0700 (PDT) From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: vincent.guittot@linaro.org, daniel.lezcano@linaro.org, Dietmar Eggemann , yuyang.du@intel.com, mturquette@baylibre.com, rjw@rjwysocki.net, Juri Lelli , sgurrappadi@nvidia.com, pang.xunlei@zte.com.cn, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: [RFCv5 PATCH 35/46] sched: Disable energy-unfriendly nohz kicks Date: Tue, 7 Jul 2015 19:24:18 +0100 Message-Id: <1436293469-25707-36-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1436293469-25707-1-git-send-email-morten.rasmussen@arm.com> References: <1436293469-25707-1-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=-7.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, 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 With energy-aware scheduling enabled nohz_kick_needed() generates many nohz idle-balance kicks which lead to nothing when multiple tasks get packed on a single cpu to save energy. This causes unnecessary wake-ups and hence wastes energy. Make these conditions depend on !energy_aware() for now until the energy-aware nohz story gets sorted out. cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Morten Rasmussen --- kernel/sched/fair.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 97eb83e..8e0cbd4 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8424,12 +8424,13 @@ static inline bool nohz_kick_needed(struct rq *rq) if (time_before(now, nohz.next_balance)) return false; - if (rq->nr_running >= 2) + if (rq->nr_running >= 2 && + (!energy_aware() || cpu_overutilized(cpu))) return true; rcu_read_lock(); sd = rcu_dereference(per_cpu(sd_busy, cpu)); - if (sd) { + if (sd && !energy_aware()) { sgc = sd->groups->sgc; nr_busy = atomic_read(&sgc->nr_busy_cpus);