From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF09FC1B0F2 for ; Wed, 20 Jun 2018 09:07:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 654D520652 for ; Wed, 20 Jun 2018 09:07:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 654D520652 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932617AbeFTJHP (ORCPT ); Wed, 20 Jun 2018 05:07:15 -0400 Received: from foss.arm.com ([217.140.101.70]:34050 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754826AbeFTJGy (ORCPT ); Wed, 20 Jun 2018 05:06:54 -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 55E0480D; Wed, 20 Jun 2018 02:06:54 -0700 (PDT) Received: from e105550-lin.cambridge.arm.com (e105550-lin.cambridge.arm.com [10.1.211.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id AF8D73F246; Wed, 20 Jun 2018 02:06:52 -0700 (PDT) From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: valentin.schneider@arm.com, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, gaku.inami.xh@renesas.com, linux-kernel@vger.kernel.org, Chris Redpath , Morten Rasmussen Subject: [PATCHv3 9/9] sched/fair: Don't move tasks to lower capacity cpus unless necessary Date: Wed, 20 Jun 2018 10:05:49 +0100 Message-Id: <1529485549-5191-10-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1529485549-5191-1-git-send-email-morten.rasmussen@arm.com> References: <1529485549-5191-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chris Redpath When lower capacity CPUs are load balancing and considering to pull something from a higher capacity group, we should not pull tasks from a cpu with only one task running as this is guaranteed to impede progress for that task. If there is more than one task running, load balance in the higher capacity group would have already made any possible moves to resolve imbalance and we should make better use of system compute capacity by moving a task if we still have more than one running. cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Chris Redpath Signed-off-by: Morten Rasmussen --- kernel/sched/fair.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index aac7b9155bc4..5d612d3906d5 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8796,6 +8796,17 @@ static struct rq *find_busiest_queue(struct lb_env *env, capacity = capacity_of(i); + /* + * For ASYM_CPUCAPACITY domains, don't pick a cpu that could + * eventually lead to active_balancing high->low capacity. + * Higher per-cpu capacity is considered better than balancing + * average load. + */ + if (env->sd->flags & SD_ASYM_CPUCAPACITY && + capacity_of(env->dst_cpu) < capacity && + rq->nr_running == 1) + continue; + wl = weighted_cpuload(rq); /* -- 2.7.4