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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 4BEDEC64E7B for ; Wed, 2 Dec 2020 16:59:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF1182173E for ; Wed, 2 Dec 2020 16:59:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387542AbgLBQ7S (ORCPT ); Wed, 2 Dec 2020 11:59:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387516AbgLBQ7R (ORCPT ); Wed, 2 Dec 2020 11:59:17 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61E4CC0613CF for ; Wed, 2 Dec 2020 08:58:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ICIwPScTyOPZq1IRDrxDK6jQadAjeRRdxNuGb4ptO54=; b=hEra2LQkMd7pHsBhc94ZlRee+N r+MbLw+7AOyVtZRHp1hllkiEmuTAXk44X3AR8e06WG//oBn9OiI7Pv17og3jl/RMDrnO4RbKK4PK0 J4TzmMbpnFgpZeExrgRzmpd8YMgmpFwC8ehkHhmEdS1rY5uE9yS3z0PSh2r8iPlrKwSI9nE5tR44Q xxUAedGKzoyE/4VFObMrMjFSjmUmYWpgnsWKcDQr0hRVzq3LU2BPLqlFLQ894jf9YIgudG20ET4PA pLMawVi0FwaKfgMAiPRejOcDIxfFRN085PhzLXOAZqio9EaR0H2lkQjHeC0JVLMf/HaPIUaJb6vtY L5GlGLvA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkVSY-0005Kk-F9; Wed, 02 Dec 2020 16:58:30 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 0D637305E21; Wed, 2 Dec 2020 17:58:29 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id E2A59201BAA71; Wed, 2 Dec 2020 17:58:28 +0100 (CET) Date: Wed, 2 Dec 2020 17:58:28 +0100 From: Peter Zijlstra To: Mel Gorman Cc: "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, qperret@google.com, viresh.kumar@linaro.org Subject: Re: [RFC] Documentation/scheduler/schedutil.txt Message-ID: <20201202165828.GC2414@hirez.programming.kicks-ass.net> References: <20201120075527.GB2414@hirez.programming.kicks-ass.net> <20201202141835.GY3306@suse.de> <20201202155452.GK3021@hirez.programming.kicks-ass.net> <20201202164531.GA3306@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201202164531.GA3306@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 02, 2020 at 04:45:31PM +0000, Mel Gorman wrote: > > > It's less obvious what the consequence is unless the reader manages to > > > tie the IO-wait comment in "Schedutil / DVFS" to this section. > > > > I'm not entirely sure I follow. The purpose of UTIL_EST is to avoid > > ramp-up issues and isn't related to IO-wait boosting. > > > > I mixed up the example. Historically io-wait boosting was one way of > avoiding DVFS ramp-up issues but now that I reread it, it's best to leave > it general like you already have in your current version. So IO-wait boosting is an interesting case; as it captures something not present in the rest of the model, namely interaction. There's also that series of patches that does the cpu/gpu interaction thing. It would be worth expanding on it, but I didn't have it in me to dig through the archives to get a coherent description of the current state of things. Something left todo later...