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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 8AAF7C432C3 for ; Fri, 15 Nov 2019 11:57:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6143C2073A for ; Fri, 15 Nov 2019 11:57:23 +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="u03liyFW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727200AbfKOL5W (ORCPT ); Fri, 15 Nov 2019 06:57:22 -0500 Received: from merlin.infradead.org ([205.233.59.134]:59600 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbfKOL5W (ORCPT ); Fri, 15 Nov 2019 06:57:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=95crfP7e+By3Ml2TQeef+TjTRr2ZLBCtzI/MPPSwg9Y=; b=u03liyFWYLOHqu2h+X9ODlgmK izGCoqdatwlPRTx76zlFyZxDsA3SmAJU5GGY0JUSnIxAUeoAQVKANXzKwHkqRoAUcYnyjMwGNVu1O HEcq2zXZnme0xeJoyxFCOsqbpp+CYNUSZ+sd5C8PF2xrLhwkLHM8ZnhXsg+nxPHJeR2g00YyLTK6Y ctFA0cxj2PW0aIU0vIbdxrYuGLKflM1QtKAQRbBGwq4H5PCuO8OgfX2Yh406IoihBce4uvSvcHh46 7mGdReKqWR/anErfTodpe4xuztt+C1TvxpAk2T5c3gIVBwJecVXVgdy9J08mBPIQFTV3x0JDpO9eA 4PoXKSeWw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iVaDQ-0007Dx-Vv; Fri, 15 Nov 2019 11:56:41 +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 87829304637; Fri, 15 Nov 2019 12:55:29 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 82BF92B128BE6; Fri, 15 Nov 2019 12:56:37 +0100 (CET) Date: Fri, 15 Nov 2019 12:56:37 +0100 From: Peter Zijlstra To: Vincent Guittot Cc: linux-kernel , Ingo Molnar , Dietmar Eggemann , Juri Lelli , Steven Rostedt , Mel Gorman , Doug Smythies , "open list:THERMAL" , Linus Torvalds , Thomas Gleixner , Sargun Dhillon , Tejun Heo , Xie XiuQi , xiezhipeng1@huawei.com, Srinivas Pandruvada Subject: Re: [PATCH v4] sched/freq: move call to cpufreq_update_util Message-ID: <20191115115637.GH4131@hirez.programming.kicks-ass.net> References: <1573751251-3505-1-git-send-email-vincent.guittot@linaro.org> <20191115095447.GU4114@hirez.programming.kicks-ass.net> <20191115103735.GE4131@hirez.programming.kicks-ass.net> <20191115105110.GG4131@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, Nov 15, 2019 at 12:03:31PM +0100, Vincent Guittot wrote: > On Fri, 15 Nov 2019 at 11:51, Peter Zijlstra wrote: > > > > On Fri, Nov 15, 2019 at 11:46:01AM +0100, Vincent Guittot wrote: > > > On Fri, 15 Nov 2019 at 11:37, Peter Zijlstra wrote: > > > > > > Sure, but then it can still remember the value passed in last and use > > > > that state later. > > > > > > > > It doesn't _have_ to completely discard values. > > > > > > yes but it means that we run at the "wrong" frequency during this > > > period and also that the cpufreq must in this case set a kind of timer > > > to resubmit a new frequency change out of scheduler event > > > > But if, as you say, we're completely shutting down the event stream > > when everything has decayed, that's still true, right? > > But It doesn't because there is nothing else to do. > > This patch does 2 things: > - fix the spurious call to cpufreq just before attaching a task > - make sure cpufreq is still called when cfs is 0 but not irq/rt or dl > > There are somehow related but not fully Right, but when everything is 0, we stop generating events because we stop calling update_blocked_average(), so there will be a last event when we hit all 0s and then nothing. So no superfluous events. And if that last event if thrown out because of rate-limiting ....