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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 10659C433B4 for ; Fri, 30 Apr 2021 08:33:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CF335613DA for ; Fri, 30 Apr 2021 08:33:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231337AbhD3Ieb (ORCPT ); Fri, 30 Apr 2021 04:34:31 -0400 Received: from foss.arm.com ([217.140.110.172]:43600 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbhD3Iea (ORCPT ); Fri, 30 Apr 2021 04:34:30 -0400 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 43327ED1; Fri, 30 Apr 2021 01:33:42 -0700 (PDT) Received: from [10.57.32.47] (unknown [10.57.32.47]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 865383F70D; Fri, 30 Apr 2021 01:33:38 -0700 (PDT) Subject: Re: [PATCH] sched/fair: Fix negative energy delta in find_energy_efficient_cpu() To: Quentin Perret Cc: linux-kernel@vger.kernel.org, xuewen.yan@unisoc.com, Lukasz.Luba@arm.com, Vincent.Donnefort@arm.com, dietmar.eggemann@arm.com, qais.yousef@arm.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, qperret@qperret.net References: <20210420125604.15796-1-Pierre.Gondois@arm.com> From: Pierre Gondois Message-ID: Date: Fri, 30 Apr 2021 09:33:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Quentin, I sent a v2 yesterday. This is just to answer your question: > Not that I disagree with the approach, just being curious: do we know > how much this is helping in practice to reduce the window by moving the > compute_energy() calls down here? I don't have any numbers. However, moving the computation of base_energy_pd after looping over the CPUs of a performance domain allows to skip this computation if no CPU is available in the performance domain. This should justify moving the compute_energy() call. Regards, Pierre