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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 0B47FC33C9E for ; Tue, 28 Jan 2020 11:34:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D292E24681 for ; Tue, 28 Jan 2020 11:34:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726024AbgA1Le0 (ORCPT ); Tue, 28 Jan 2020 06:34:26 -0500 Received: from foss.arm.com ([217.140.110.172]:55506 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725903AbgA1LeZ (ORCPT ); Tue, 28 Jan 2020 06:34:25 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 422A6101E; Tue, 28 Jan 2020 03:34:23 -0800 (PST) Received: from [10.1.194.46] (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3C8533F52E; Tue, 28 Jan 2020 03:34:22 -0800 (PST) Subject: Re: [PATCH v3 0/3] sched/fair: Capacity aware wakeup rework To: Dietmar Eggemann , linux-kernel@vger.kernel.org Cc: mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, morten.rasmussen@arm.com, qperret@google.com, adharmap@codeaurora.org References: <20200126200934.18712-1-valentin.schneider@arm.com> <35c18eee-7e92-8a7d-c59d-11dfd2b053ff@arm.com> From: Valentin Schneider Message-ID: <9b6d0ea2-cf5e-ed89-6c08-6f43c345265f@arm.com> Date: Tue, 28 Jan 2020 11:34:21 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <35c18eee-7e92-8a7d-c59d-11dfd2b053ff@arm.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 28/01/2020 09:24, Dietmar Eggemann wrote: > On 26/01/2020 21:09, Valentin Schneider wrote: > > [...] > >> v2 -> v3 >> -------- >> o Added missing sync_entity_load_avg() (Quentin) >> o Added fallback CPU selection (maximize capacity) >> o Added special case for CPU hogs: task_fits_capacity() will always return 'false' >> for tasks that are simply too big, due to the margin. > > v3 fixes the Geekbench multicore regression I saw on Pixel4 (Android 10, > Android Common Kernel v4.14 based, Snapdragon 855) running v1. > > I changed the Pixel4 kernel a bit (PELT instead WALT, mainline > select_idle_sibling() instead the csctate aware one), mainline > task_fits_capacity()) for base, v1 & v3. > > Since it's not mainline kernel the results have to be taken with a pinch > of salt but they probably show that the new condition: > > if (rq->cpu_capacity_orig == READ_ONCE(rq->rd->max_cpu_capacity) && ... > return cpu; > > has an effect when dealing with tasks with util_est values > 0.8 * 1024. > Thanks for going through that hassle! I'm quite pleased with the results of that change - if you also look at e.g. the stddev for sysbench on Juno, runs are much more consistent now.