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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 E6EEAC4646D for ; Mon, 6 Aug 2018 10:33:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A066821A03 for ; Mon, 6 Aug 2018 10:33:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linaro.org header.i=@linaro.org header.b="H2nZh8F6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A066821A03 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org 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 S1729825AbeHFMmQ (ORCPT ); Mon, 6 Aug 2018 08:42:16 -0400 Received: from mail-it0-f68.google.com ([209.85.214.68]:51105 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727517AbeHFMmQ (ORCPT ); Mon, 6 Aug 2018 08:42:16 -0400 Received: by mail-it0-f68.google.com with SMTP id j81-v6so14959947ite.0 for ; Mon, 06 Aug 2018 03:33:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=PzuIBXiYr2yEqrM0q9et4p1OWpyCzWNpJcyYEFtLMYI=; b=H2nZh8F6r4GSFIzz3bkvmMUI7feP2ie+c3bFsgbtayTdgP8uS/3ngORUKncKhEH4W4 tuK8OkWMdkeNuzkE0EpI52ZJBQTto3iYaBVjnx3OeT3v0w2XBaFYCmN0m68D6ATA7ABB usajGjIRopSmIYTS+0uWgi/669+ITHZcCgdp8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=PzuIBXiYr2yEqrM0q9et4p1OWpyCzWNpJcyYEFtLMYI=; b=ROVniJrrsaow7aHwo6+0FudU8cNQjWU6HYQzDA8ahaGY9lYEpXl8Eul92w712WIoSA K+Y6Ef3PqyuCiaEO9Fx9cjBB7UeFLeqnVmKqSnVpV8Cm6SynyPEvst7zDpzSzKDjHlYt +cMWEycKCf/Jtrw+J+ndiE/zfxApyO0hEgJgJvTbG/rwpfxBOFWmOdrIY8OusZauQwxb cwm73cfVLfN8xF4BrRv++GNnBdWWKR6l1hkbvPhBdaNKbVHgm2pIxm8JRMNfW1ZkFAtv ClmimQdtAnsYDvoFWv09f4BZbqVTT7Omjl0/ytJ41bQhueJAnErZWwTMHdLH4AwRGygZ kTTQ== X-Gm-Message-State: AOUpUlGDzNudbHRYh8IHA2iZ7PW5d+Wp8Lg+uGKnOW7AFDUyv+syi8Wf PKYHZxZMN0Aw+5uNoZWSO0p39IP/eJ4e/Kti3w2A7w== X-Google-Smtp-Source: AAOMgpd8dKEeAUhCu82kvKEKybe2PP1qL3NChdhEQ57cwMgE2I+gwnGQrlVJ5uJwBuFDcwka8arpS/uYtfkhpjDvPMU= X-Received: by 2002:a02:4c16:: with SMTP id a22-v6mr11706467jab.48.1533551630093; Mon, 06 Aug 2018 03:33:50 -0700 (PDT) MIME-Version: 1.0 References: <20180802153035.vjtmqwdwujvt7ojs@queper01-lin> <20180802160009.uhwwj3tqrqmv7q5a@queper01-lin> <20180802161027.v2ctgscuc4uxbb7u@queper01-lin> <20180802165924.7ywgoxj2jwftxycz@queper01-lin> <20180803081850.hj7bp5ognuywapmd@queper01-lin> <20180803155547.sxlhxpmhwcoappit@queper01-lin> <68689fcb-3cb8-4685-58ef-0bec84be2047@arm.com> In-Reply-To: <68689fcb-3cb8-4685-58ef-0bec84be2047@arm.com> From: Vincent Guittot Date: Mon, 6 Aug 2018 12:33:39 +0200 Message-ID: Subject: Re: [PATCH v5 09/14] sched: Add over-utilization/tipping point indicator To: Dietmar Eggemann Cc: Quentin Perret , Peter Zijlstra , "Rafael J. Wysocki" , linux-kernel , "open list:THERMAL" , "gregkh@linuxfoundation.org" , Ingo Molnar , Morten Rasmussen , Chris Redpath , Patrick Bellasi , Valentin Schneider , Thara Gopinath , viresh kumar , Todd Kjos , Joel Fernandes , "Cc: Steve Muckle" , adharmap@quicinc.com, "Kannan, Saravana" , pkondeti@codeaurora.org, Juri Lelli , Eduardo Valentin , Srinivas Pandruvada , currojerez@riseup.net, Javi Merino Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 6 Aug 2018 at 12:08, Dietmar Eggemann wrote: > > On 08/06/2018 10:40 AM, Vincent Guittot wrote: > > On Fri, 3 Aug 2018 at 17:55, Quentin Perret wrote: > >> > >> On Friday 03 Aug 2018 at 15:49:24 (+0200), Vincent Guittot wrote: > >>> On Fri, 3 Aug 2018 at 10:18, Quentin Perret wrote: > >>>> > >>>> On Friday 03 Aug 2018 at 09:48:47 (+0200), Vincent Guittot wrote: > >>>>> On Thu, 2 Aug 2018 at 18:59, Quentin Perret wrote: > > [...] > > >> I think we're discussing two different things right now: > >> 1. Should forkees go in find_energy_efficient_cpu() ? > >> 2. Should forkees have 0 of initial util_avg when EAS is enabled ? > > > > It's the same topic: How EAS should consider a newly created task ? > > > > For now, we let the "performance" mode selects a CPU. This CPU will > > most probably be worst CPU from a EAS pov because it's the idlest CPU > > in the idlest group which is the opposite of what EAS tries to do > > > > The current behavior is : > > For every new task, the cpu selection is done assuming it's a heavy > > task with the max possible load_avg, and it looks for the idlest cpu. > > This means that if the system is lightly loaded, scheduler will select > > most probably a idle big core. > > AFAICS, task load doesn't seem to be used for find_idlest_cpu() ( > find_idlest_group() and find_idlest_group_cpu()). So the forkee > (SD_BALANCE_FORK) is placed independently of his task load. hmm ... so what is used if load or runnable load are not used ? find_idlest_group() uses load and runnable load but skip spare capacity in case of fork > Task load (task_h_load(p)) is used in > wake_affine()->wake_affine_weight() but for this to be called it has to > be a wakeup (SD_BALANCE_WAKE). > > > The utilization of this new task is then set to half of the remaining > > capacity of the selected CPU which means that the idlest you are, the > > biggest the task will be initialized to. This can easily be half a big > > core which can be bigger than the max capacity of a little like on > > hikey960. Then, util_est will keep track of this value for a while > > which will make this task like a big one. > > [...] >