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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 E69C5C43142 for ; Fri, 22 Jun 2018 13:30:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F604242B9 for ; Fri, 22 Jun 2018 13:30:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jYgD8EKM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F604242B9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.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 S1753272AbeFVNaD (ORCPT ); Fri, 22 Jun 2018 09:30:03 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:55284 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751326AbeFVNaC (ORCPT ); Fri, 22 Jun 2018 09:30:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=LT7ImzVWiBZpgym+tQ+mOnSxLR2LXR8uiW+BKlQtmtk=; b=jYgD8EKMUlBcg1ToI6foZFrdl PUzkTomfrFrlFdfBHWWateCDmOj8uxog8AiKRIcTq1KYFE0qoLhJgsPlTRsDKlc5pwlW0YsTRcsa0 0q2/BPBVZIdQXb8vKBTMwLD9moTQ5i5jNl5oRYnqQNDesbSgVnAlna+xSkGtKFIEkvQP3zlSU04+g gCSsD0KgdFewNVTsGNhqLdwlJrNNJ3qY6BJ2z5322fMNMA8ffleJ6V6AbqQeXhdKAtgDzpm55SVQR ownrTl3wyXGG+lYAN0XlxaFBEc6FrRE4gtClPw8Us0a4XrhA4bh4KQb5R9lLvOhQMgGgdruIIbW9T QMjA9xOsw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fWM8R-0005nZ-2d; Fri, 22 Jun 2018 13:29:55 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9219E2029F1D7; Fri, 22 Jun 2018 15:29:53 +0200 (CEST) Date: Fri, 22 Jun 2018 15:29:53 +0200 From: Peter Zijlstra To: Quentin Perret Cc: Vincent Guittot , mingo@kernel.org, linux-kernel@vger.kernel.org, rjw@rjwysocki.net, juri.lelli@redhat.com, dietmar.eggemann@arm.com, Morten.Rasmussen@arm.com, viresh.kumar@linaro.org, valentin.schneider@arm.com, patrick.bellasi@arm.com, joel@joelfernandes.org, daniel.lezcano@linaro.org, Ingo Molnar Subject: Re: [PATCH v6 04/11] cpufreq/schedutil: use rt utilization tracking Message-ID: <20180622132953.GM2494@hirez.programming.kicks-ass.net> References: <1528459794-13066-1-git-send-email-vincent.guittot@linaro.org> <1528459794-13066-5-git-send-email-vincent.guittot@linaro.org> <20180621184524.GB27616@hirez.programming.kicks-ass.net> <20180622075853.GC23168@e108498-lin.cambridge.arm.com> <20180622113713.GJ2494@hirez.programming.kicks-ass.net> <20180622125433.GA26461@e108498-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180622125433.GA26461@e108498-lin.cambridge.arm.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 22, 2018 at 01:54:34PM +0100, Quentin Perret wrote: > On Friday 22 Jun 2018 at 13:37:13 (+0200), Peter Zijlstra wrote: > > That is true.. So we could limit the scaling to the case where there is > > no idle time, something like: > > > > util = sg_cpu->util_cfs; > > > > cap_cfs = (1024 - (sg_cpu->util_rt + ...)); > > if (util == cap_cfs) > > util = sg_cpu->max; > > > > That specifically handles the '0% idle -> 100% freq' case, but I don't > > realy like edge behaviour like that. If for some reason it all doesn't > > quite align you're left with bits. > > > > And the linear scaling is the next simplest thing that avoids the hard > > boundary case. > > Right, so maybe we'll get something smoother by just summing the signals > as Vincent is proposing ? Sure, but see my previous mail just now, that has the problem of u_{rt,dl} distoting f_{rt,dl} even when there is no u_cfs.