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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 40821C3279B for ; Fri, 6 Jul 2018 13:40:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA0B423CD9 for ; Fri, 6 Jul 2018 13:40:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA0B423CD9 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 S933079AbeGFNkK (ORCPT ); Fri, 6 Jul 2018 09:40:10 -0400 Received: from foss.arm.com ([217.140.101.70]:37014 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753533AbeGFNkJ (ORCPT ); Fri, 6 Jul 2018 09:40:09 -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 2B9EAED1; Fri, 6 Jul 2018 06:40:09 -0700 (PDT) Received: from e108498-lin.cambridge.arm.com (e108498-lin.cambridge.arm.com [10.1.211.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 38BD13F5AD; Fri, 6 Jul 2018 06:40:05 -0700 (PDT) Date: Fri, 6 Jul 2018 14:40:03 +0100 From: Quentin Perret To: Peter Zijlstra Cc: rjw@rjwysocki.net, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, gregkh@linuxfoundation.org, mingo@redhat.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, chris.redpath@arm.com, patrick.bellasi@arm.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, thara.gopinath@linaro.org, viresh.kumar@linaro.org, tkjos@google.com, joel@joelfernandes.org, smuckle@google.com, adharmap@quicinc.com, skannan@quicinc.com, pkondeti@codeaurora.org, juri.lelli@redhat.com, edubezval@gmail.com, srinivas.pandruvada@linux.intel.com, currojerez@riseup.net, javi.merino@kernel.org Subject: Re: [RFC PATCH v4 08/12] sched: Add over-utilization/tipping point indicator Message-ID: <20180706134003.GB17577@e108498-lin.cambridge.arm.com> References: <20180628114043.24724-1-quentin.perret@arm.com> <20180628114043.24724-9-quentin.perret@arm.com> <20180706113208.GS2458@hirez.programming.kicks-ass.net> <20180706132056.GA17577@e108498-lin.cambridge.arm.com> <20180706132428.GY2476@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180706132428.GY2476@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 06 Jul 2018 at 15:24:28 (+0200), Peter Zijlstra wrote: > On Fri, Jul 06, 2018 at 02:20:57PM +0100, Quentin Perret wrote: > > So, what we try to do here is to _not_ set the overutilized flag based > > on the utilization of a new task, because its utilization is 'wrong'. > > That should help avoiding spurious transitions above the overutilized > > threshold. > > That most certainly deserves a comment, Ok, will do. > also didn't util_est fix some of that wrong-ness? When a new task is enqueued, we don't have util_est samples yet, so the task's util_est is equal to its util_avg. So util_est won't help here, unfortunately. But it does help in the wake-up path to predict what OPP will be selected (see cpu_util_next() in patch 09/12). Thanks, Quentin