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 C82F2C43142 for ; Fri, 22 Jun 2018 11:44:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E08D23C3F for ; Fri, 22 Jun 2018 11:44:38 +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="qDU6gai3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E08D23C3F 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 S1752416AbeFVLog (ORCPT ); Fri, 22 Jun 2018 07:44:36 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:41396 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751303AbeFVLof (ORCPT ); Fri, 22 Jun 2018 07:44:35 -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=mKkPZLdHycawzLZZbOI4Ex486oiK4bYS9vXZfCjfaUk=; b=qDU6gai3QPNAXrfNavRf7r1QU 2kR2ujmq1r4Q4ZTlzCL4TxSJC04wybXSOY8HKNxhHZnG61MHYe9ACoaNwnVZt+lSCM8gLEBfqq2mP Y0v3nmRzYjJQEYS5t20bdqXHLMthWQ0wNRmdiQYxgPxU35ltzy9LHhMUeFpsRt7pjaWosCZ0Ux6PQ JJFXS/cAC9/hNy6eh1993n12jLHmdnRX0mDyEzUSk+KY1Ppud85c/P5MRxYkRBH8eOVD77s+JCPf2 /inOzare1rZvFZo9fOK3xIarto/nNXie2OvnVlNcgMgzhyA99aiaCOqHvQNXQm+TnVsWn2cnV9uTV DQlqUooAA==; 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 1fWKUO-0002jF-SR; Fri, 22 Jun 2018 11:44:29 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 89EFD2029FA0A; Fri, 22 Jun 2018 13:44:26 +0200 (CEST) Date: Fri, 22 Jun 2018 13:44:26 +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: <20180622114426.GC2512@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180622113713.GJ2494@hirez.programming.kicks-ass.net> 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 01:37:13PM +0200, Peter Zijlstra wrote: > I suppose we can make it more complicated, something like: > > u u > f := u + (--- - u) * (---)^n > 1-r 1-r > > Where: u := cfs util > r := \Sum !cfs util > f := frequency request > > That would still satisfy all criteria I think: > > r = 0 -> f := u > u = (1-r) -> f := 1 > > and in particular: > > u << (1-r) -> f ~= u > > which casuses less inflation than the linear thing where there is idle > time. Note that for n=0 this last property is lost and we have the initial linear case back.