From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1524214647; cv=none; d=google.com; s=arc-20160816; b=ggbfYEPjW66jv7OhojVPFreao1wtqNp+MVUNa3EqfZm/pGwDpPMOOhrr+hCaiNGji8 X6OA6FNQqDCudrOViWJ9SrUQXRpdU1MNhvIEbFkGANTJaMdokbd3HuNTuy93T60mDWpU qJX12NLGoihHnUBwr7nbv+QbPcMbJedPxLMw1ZycgrwJW9nZjousptyzMtuCzHKvQNip 4ZZtXfSzhk4rVGjNkLNkjyKo4sfDQCtQAVaRlIZJl/XT78wzRFlv35ct/5SRsbBsUCD3 JgfhZEin/8R9CqugvLozD2AnloUfoRkfPAJY5bYxfTcSeVd/Tdxz0CT7596vpq+iMXXr jI1Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:arc-authentication-results; bh=8IZAySK+ZNwbbsd60vhvY/nKlpaHuRhBttE/IQQEsRU=; b=bA8liWPQnIKFKj6ttmf7wXjzjMsr6k4vVFeNzmfStjJNUs0z9by90USHuE8h3HX7kv EpDbGCcA2NaK0A/LXA0Nt5nR7fZcavurFabEXm+p0pzXtkovNHaU6Xf2+kToY0LPK6qx OyCMbOQAjQ75k4YthwdXIEPuYV/kPq7BULm+v7/EliGr2knjwdR0ZprzNxz0KC/864St k8j9TD8s1rPkr5R2P5JCXo7voz9CQNZmqCnI1Xow2fCX1M9NsOb7tNdwR+oNSkVn29FJ YXrCTP0u/RQ6/o6cj1XS6j2kXT+STzIgte+BbdldbuKeRdCf7RoEecOSJ30ca6kKcrQe vY2A== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of juri.lelli@redhat.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=juri.lelli@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of juri.lelli@redhat.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=juri.lelli@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Google-Smtp-Source: AIpwx49uKY7eL5oyATDIMyb+KHXu2oDyTuVJ2yKdlwegLf3jRLdw/qBGfb8U1FS4VHOzOXYHitgmYQ== Date: Fri, 20 Apr 2018 10:57:23 +0200 From: Juri Lelli To: Quentin Perret Cc: Joel Fernandes , Dietmar Eggemann , LKML , Peter Zijlstra , Thara Gopinath , Linux PM , Morten Rasmussen , Chris Redpath , Patrick Bellasi , Valentin Schneider , "Rafael J . Wysocki" , Greg Kroah-Hartman , Vincent Guittot , Viresh Kumar , Todd Kjos , Steve Muckle , Eduardo Valentin Subject: Re: [RFC PATCH v2 3/6] sched: Add over-utilization/tipping point indicator Message-ID: <20180420085723.GE24599@localhost.localdomain> References: <20180406153607.17815-1-dietmar.eggemann@arm.com> <20180406153607.17815-4-dietmar.eggemann@arm.com> <20180418111729.GB6783@e108498-lin.cambridge.arm.com> <20180420083118.GA14391@e108498-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180420083118.GA14391@e108498-lin.cambridge.arm.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597011684825023112?= X-GMAIL-MSGID: =?utf-8?q?1598254899044485138?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 20/04/18 09:31, Quentin Perret wrote: > On Friday 20 Apr 2018 at 01:14:35 (-0700), Joel Fernandes wrote: > > On Fri, Apr 20, 2018 at 1:13 AM, Joel Fernandes wrote: > > > On Wed, Apr 18, 2018 at 4:17 AM, Quentin Perret wrote: > > >> On Friday 13 Apr 2018 at 16:56:39 (-0700), Joel Fernandes wrote: [...] > > >>> > > >>> I'm wondering if it makes sense for considering scenarios whether > > >>> other classes cause CPUs in the domain to go above the tipping point. > > >>> Then in that case also, it makes sense to not to do EAS in that domain > > >>> because of the overutilization. > > >>> > > >>> I guess task_fits using cpu_util which is PELT only at the moment... > > >>> so may require some other method like aggregation of CFS PELT, with > > >>> RT-PELT and DL running bw or something. > > >>> > > >> > > >> So at the moment in cpu_overutilized() we comapre cpu_util() to > > >> capacity_of() which should include RT and IRQ pressure IIRC. But > > >> you're right, we might be able to do more here... Perhaps we > > >> could also use cpu_util_dl() which is available in sched.h now ? > > > > > > Yes, should be Ok, and then when RT utilization stuff is available, > > > then that can be included in the equation as well (probably for now > > > you could use rt_avg). > > > > > > Another crazy idea is to check the contribution of higher classes in > > > one-shot with (capacity_orig_of - capacity_of) although I think that > > > method would be less instantaneous/accurate. > > > > Just to add to the last point, the capacity_of also factors in the IRQ > > contribution if I remember correctly, which is probably a good thing? > > > > I think so too yes. But actually, since we compare cpu_util() to > capacity_of() in cpu_overutilized(), the current implementation should > already be fairly similar to the "capacity_orig_of - capacity_of" > implementation you're suggesting I guess. > And I agree that when Vincent's RT PELT patches get merged we should > probably use that :-) Mind that rt_avg contains DL contribution as well ATM https://elixir.bootlin.com/linux/v4.17-rc1/source/kernel/sched/deadline.c#L1182 So you shouldn't add newer DL utilization signal to it. OTOH, using RT PELT (once in) is of course to be preferred. Best, - Juri