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=-2.4 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 B450DC43142 for ; Thu, 2 Aug 2018 12:26:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 605822150B for ; Thu, 2 Aug 2018 12:26:46 +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="W8Nd/s3d" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 605822150B 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 S1732390AbeHBORl (ORCPT ); Thu, 2 Aug 2018 10:17:41 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:52086 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732034AbeHBORl (ORCPT ); Thu, 2 Aug 2018 10:17:41 -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=09Y+oiJ6OuY7A5bT81gZvt+MplKry8zPB717wEAV2O0=; b=W8Nd/s3d+tii55H20I5/Tns16 X153NbdzBIUJxQTXi6P5HWrMU+Z/v9RLQ+GqFywWraKjd5pwAZp9tSW92oKoqKTULHaXKA2/U8jXu UOsIo6W4o7CaTWHQ8O9CN2LuK+Wa4vBb1vdwdKhD9WcAomjtmvEzrx0xp2MpaNbDatFLrqrHR4PeU oYey/jzwxR5iIrzmv0lhr/0TqzwEY2//ISNKLonK2po4cs/D8Lk3JugfsI4kbU2b+Bmrn5Kwa6E6f 0NWDTYVbOHpN1PSxoyOCfhwF/xW+5QYT887fXbfukhHfFdu1qDw2+UJ2MwxWT8sSRlSOq0OWdopXM 0qUu9HzPQ==; 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 1flCga-0002BJ-0N; Thu, 02 Aug 2018 12:26:32 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A667D20268263; Thu, 2 Aug 2018 14:26:29 +0200 (CEST) Date: Thu, 2 Aug 2018 14:26:29 +0200 From: Peter Zijlstra To: Quentin Perret 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: [PATCH v5 09/14] sched: Add over-utilization/tipping point indicator Message-ID: <20180802122629.GU2476@hirez.programming.kicks-ass.net> References: <20180724122521.22109-1-quentin.perret@arm.com> <20180724122521.22109-10-quentin.perret@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180724122521.22109-10-quentin.perret@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 Tue, Jul 24, 2018 at 01:25:16PM +0100, Quentin Perret wrote: > @@ -5100,8 +5118,17 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) > update_cfs_group(se); > } > > - if (!se) > + if (!se) { > add_nr_running(rq, 1); > + /* > + * The utilization of a new task is 'wrong' so wait for it > + * to build some utilization history before trying to detect > + * the overutilized flag. > + */ > + if (flags & ENQUEUE_WAKEUP) > + update_overutilized_status(rq); > + > + } > > hrtick_update(rq); > } That is a somewhat dodgy hack. There is no guarantee what so ever that when the task wakes next its history is any better. The comment doesn't reflect this I feel.