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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 099D5C43441 for ; Wed, 10 Oct 2018 13:11:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF30D2085B for ; Wed, 10 Oct 2018 13:11:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CF30D2085B 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 S1727170AbeJJUdj (ORCPT ); Wed, 10 Oct 2018 16:33:39 -0400 Received: from foss.arm.com ([217.140.101.70]:52232 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726206AbeJJUdi (ORCPT ); Wed, 10 Oct 2018 16:33:38 -0400 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 1920AED1; Wed, 10 Oct 2018 06:11:31 -0700 (PDT) Received: from queper01-lin (queper01-lin.cambridge.arm.com [10.1.195.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4B0693F5D3; Wed, 10 Oct 2018 06:11:28 -0700 (PDT) Date: Wed, 10 Oct 2018 14:11:26 +0100 From: Quentin Perret To: Juri Lelli Cc: Vincent Guittot , Ingo Molnar , Thara Gopinath , linux-kernel , Ingo Molnar , Peter Zijlstra , Zhang Rui , "gregkh@linuxfoundation.org" , "Rafael J. Wysocki" , Amit Kachhap , viresh kumar , Javi Merino , Eduardo Valentin , Daniel Lezcano , "open list:THERMAL" , Ionela Voinescu Subject: Re: [RFC PATCH 0/7] Introduce thermal pressure Message-ID: <20181010131124.isexblzzvkcp26q4@queper01-lin> References: <20181010061751.GA37224@gmail.com> <20181010082933.4ful4dzk7rkijcwu@queper01-lin> <20181010095459.orw2gse75klpwosx@queper01-lin> <20181010103623.ttjexasymdpi66lu@queper01-lin> <20181010122348.GL9130@localhost.localdomain> <20181010125033.GP9130@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181010125033.GP9130@localhost.localdomain> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 10 Oct 2018 at 14:50:33 (+0200), Juri Lelli wrote: > On 10/10/18 14:34, Vincent Guittot wrote: > > Hi Juri, > > > > On Wed, 10 Oct 2018 at 14:23, Juri Lelli wrote: > > > > > > On 10/10/18 14:04, Vincent Guittot wrote: > > > > > > [...] > > > > > > > The problem was the same with RT, the cfs utilization was lower than > > > > reality because RT steals soem cycle to CFS > > > > So schedutil was selecting a lower frequency when cfs was running > > > > whereas the CPU was fully used. > > > > The same can happen with thermal: > > > > cap the max freq because of thermal > > > > the utilization with decrease. > > > > remove the cap > > > > the utilization is still low and you will select a low OPP because you > > > > don't take into account cycle stolen by thermal like with RT > > > > > > What if we scale frequency component considering the capped temporary > > > max? > > > > Do you mean using a kind of scale_thermal_capacity in accumulate_sum > > when computing utilization ? > > Yeah, something like that I guess. So that we account for temporary > "fake" 1024.. But wouldn't that break frequency invariance ? A task would look bigger on a capped CPU than a non-capped one no ?