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=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 D847DC6379F for ; Fri, 20 Nov 2020 09:27:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7498D222BA for ; Fri, 20 Nov 2020 09:27:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="lEfJ1DDq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727436AbgKTJ1a (ORCPT ); Fri, 20 Nov 2020 04:27:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727312AbgKTJ1a (ORCPT ); Fri, 20 Nov 2020 04:27:30 -0500 Received: from mail-wr1-x436.google.com (mail-wr1-x436.google.com [IPv6:2a00:1450:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6A45C0613CF for ; Fri, 20 Nov 2020 01:27:29 -0800 (PST) Received: by mail-wr1-x436.google.com with SMTP id 23so9279263wrc.8 for ; Fri, 20 Nov 2020 01:27:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=ETHeYbN6hBpTG62cbJNz0JDBf9vI0VaNEPAJRWU9xC0=; b=lEfJ1DDqui1+HfYPrsT0dk46sBjS8FTGqAl7VV2pCRfosbO/VdvtXDKsDcqKCCdhbn N545BqEmmJtVMEO61BrL6zHc87uhHuX7MGufM6xFyip8oeKjUo8rL8uxQrpaVv7L2ERw 2MQKBA0lHfVfOa85YwhxPmhdVuISu1vIgNpN7nmDk3pBrP8SLXRgLCsrJ90eQmEMgavR FqrzcYPqXu0sJF2ZkffAJBbvaYncDN7SGt2SlxaTpy9MMz73yGPGG+qK0lPxS0Y6tzx3 mPzlzA3+bZvrBUO4Nt+xy+VIH3SmL0DqlssAqwSkYKJPBWbfLNTUsCuyoPWM/22DqiOM cCEg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=ETHeYbN6hBpTG62cbJNz0JDBf9vI0VaNEPAJRWU9xC0=; b=LYvCqIoXqrT3YB3CmZKqI08c1untZHZKcRzrLoyK3TPBj35XTgoqt5o7thGD+nJlsB 6XVApWVoij5SSb+2ecNQ0FgmSaAOpYFQfaeiVlsCa1TaE5hzm+z0HltPMcK5HttiFPrA 9xdM9aJUrpzL/coSoRxTPaRqhUDaSJbzM9hJx8NRXeqdqtiDegghKIeAAzaSFJWAmxoh Bvry8IkbuDUzt4IdyTpgSBABjxyIDT7beSzBSibNHhFW2n+k90tlSj+XapXC2BXMBSZt gB3EYFKwwaZlbyyiJfhNqgmFmz52ZtE7upMGY22Ar5vHcumIk8YbxKpeH3A76E6mLYXd j9Ng== X-Gm-Message-State: AOAM532MDCKhXUN4ySIKW/bLfKl23qI4gCOOh5pJocCk7KBv0heXLAPN e/VdE/aPZBuxtFlqZuk3/qenCA== X-Google-Smtp-Source: ABdhPJwFzel9kSZkOmP6r8U5b51jx3UJiaUzkIxD3haslzkIVE8CtmMY4yN939lxl+JNFkDui6j6cA== X-Received: by 2002:a5d:4e4c:: with SMTP id r12mr14845723wrt.348.1605864448213; Fri, 20 Nov 2020 01:27:28 -0800 (PST) Received: from google.com ([2a00:79e0:d:210:f693:9fff:fef4:a7ef]) by smtp.gmail.com with ESMTPSA id c5sm4291172wrb.64.2020.11.20.01.27.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Nov 2020 01:27:27 -0800 (PST) Date: Fri, 20 Nov 2020 09:27:24 +0000 From: Quentin Perret To: Viresh Kumar Cc: Peter Zijlstra , "Rafael J. Wysocki" , Ingo Molnar , Thomas Gleixner , Vincent Guittot , Morten Rasmussen , dietmar.eggemann@arm.com, patrick.bellasi@matbug.net, lenb@kernel.org, linux-kernel@vger.kernel.org, valentin.schneider@arm.com, ionela.voinescu@arm.com Subject: Re: [RFC] Documentation/scheduler/schedutil.txt Message-ID: <20201120092724.GB2653684@google.com> References: <20201120075527.GB2414@hirez.programming.kicks-ass.net> <20201120085653.GA3092@hirez.programming.kicks-ass.net> <20201120091356.GA2653684@google.com> <20201120091904.6zvovj2yxjxtnq2x@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201120091904.6zvovj2yxjxtnq2x@vireshk-i7> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 20 Nov 2020 at 14:49:04 (+0530), Viresh Kumar wrote: > This is unlikely to be an issue on systems where cpufreq policies are > shared between multiple CPUs, because in those cases the policy > utilization is computed as the maximum of the CPU utilization values > over the whole policy and if that turns out to be low, reducing the > frequency for the policy most likely is a good idea anyway. Hmm, I'm not sure I agree with this actually. We may be migrating the task to a different policy altogether. And even if we migrate to another CPU in the current policy, the task util_avg may be small just because it was packed with other tasks on a rq, which means it may not increase the util of the destination rq by much. ISTR Douglas' EM-based schedutil boosting series was addressing that at some point, I'll go have a look back at that discussion...