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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 AC3A4C3279B for ; Wed, 4 Jul 2018 10:19:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6166E20BEC for ; Wed, 4 Jul 2018 10:19:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6166E20BEC 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 S934695AbeGDKTV (ORCPT ); Wed, 4 Jul 2018 06:19:21 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:35094 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934162AbeGDKS2 (ORCPT ); Wed, 4 Jul 2018 06:18:28 -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 980AE1529; Wed, 4 Jul 2018 03:18:28 -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 F226A3F5AD; Wed, 4 Jul 2018 03:18:26 -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: [PATCHv4 10/12] sched/fair: Don't move tasks to lower capacity cpus unless necessary Date: Wed, 4 Jul 2018 11:17:48 +0100 Message-Id: <1530699470-29808-11-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1530699470-29808-1-git-send-email-morten.rasmussen@arm.com> References: <1530699470-29808-1-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 de84f5a9a65a..06beefa02420 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8793,6 +8793,17 @@ 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