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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 7DD20C04EB8 for ; Sat, 8 Dec 2018 18:39:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3CDD02081C for ; Sat, 8 Dec 2018 18:39:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3CDD02081C 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 S1726227AbeLHSj2 (ORCPT ); Sat, 8 Dec 2018 13:39:28 -0500 Received: from foss.arm.com ([217.140.101.70]:34248 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726142AbeLHSj2 (ORCPT ); Sat, 8 Dec 2018 13:39:28 -0500 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 65FA9EBD; Sat, 8 Dec 2018 10:39:27 -0800 (PST) Received: from [10.0.2.15] (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BB5D53F575; Sat, 8 Dec 2018 10:39:24 -0800 (PST) Subject: Re: [PATCH v4 08/10] sched/fair: Steal work from an overloaded CPU when CPU goes idle To: Steven Sistare , mingo@redhat.com, peterz@infradead.org Cc: subhra.mazumdar@oracle.com, dhaval.giani@oracle.com, daniel.m.jordan@oracle.com, pavel.tatashin@microsoft.com, matt@codeblueprint.co.uk, umgwanakikbuti@gmail.com, riel@redhat.com, jbacik@fb.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, quentin.perret@arm.com, linux-kernel@vger.kernel.org References: <1544131696-2888-1-git-send-email-steven.sistare@oracle.com> <1544131696-2888-9-git-send-email-steven.sistare@oracle.com> <9f798c5d-f58a-e1fc-5b03-6598e04916bb@oracle.com> From: Valentin Schneider Message-ID: <3d017a5d-50a4-3e99-c3c8-9b3ee240d076@arm.com> Date: Sat, 8 Dec 2018 18:39:21 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <9f798c5d-f58a-e1fc-5b03-6598e04916bb@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/12/2018 22:36, Steven Sistare wrote: > On 12/7/2018 3:21 PM, Valentin Schneider wrote: >> Hi Steve, >> >> On 06/12/2018 21:28, Steve Sistare wrote: >> [...] >>> @@ -6778,20 +6791,22 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ >>> update_misfit_status(NULL, rq); >>> >>> /* >>> - * We must set idle_stamp _before_ calling idle_balance(), such that we >>> - * measure the duration of idle_balance() as idle time. >>> + * We must set idle_stamp _before_ calling try_steal() or >>> + * idle_balance(), such that we measure the duration as idle time. >>> */ >>> rq_idle_stamp_update(rq); >> >> idle_balance() has a >> >> /* >> * Do not pull tasks towards !active CPUs... >> */ >> if (!cpu_active(this_cpu)) >> return 0; >> >> check which we probably want for stealing too, so we could hoist it up here >> to cover both idle_balance() and try_steal(). > > try_steal() already checks cpu_active. I could hoist it. > Ah yeah I missed that one, I had only seen cpu_active(src_cpu) in steal_from(). It's all good then. [...]