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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DCE4CA0EEC for ; Tue, 12 Sep 2023 14:28:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235899AbjILO2d (ORCPT ); Tue, 12 Sep 2023 10:28:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231629AbjILO2b (ORCPT ); Tue, 12 Sep 2023 10:28:31 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63CE7110; Tue, 12 Sep 2023 07:28:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=gk/9rYB7/an+iLUFV0aLbLxXVYBQ+i5HvJgnM5j31Ck=; b=Fyh3eDhp+bMke+9/vqft1ssk0u K26AKRckbeIkVO6fwlvCUaguX+jW9DTHl9KN5PvnMoIW9yRNl/+OK2496aleokV1T5ZtsU5fmOD0B Zr2J0fVLnb+oRoid8vba39T9Xl8js/gtSTQeRLLb0gP8wJD1PaLIem9aVMy6WsjczwtvzH1XOwkBh HaiXrQeJU9uJ23G1TlqWDBj7Oby5rpqQa88e6Xky/nossK7i99FUhKhypBj6Y6rHinDvXThtPGEDM Z6I0/uG8zv54kLWPtxSnWM90o2+NxHtkqvkwY4mXAy99Jp+6c3T3Z95JkirS6H8FidEmfn7y8LLpr mLiMrZuQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1qg4NJ-00843H-Ki; Tue, 12 Sep 2023 14:28:21 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 47E57300348; Tue, 12 Sep 2023 16:28:21 +0200 (CEST) Date: Tue, 12 Sep 2023 16:28:21 +0200 From: Peter Zijlstra To: Lukasz Luba Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Ingo Molnar , Dietmar Eggemann , Vincent Guittot , Viresh Kumar , Qais Yousef , Chris Redpath Subject: Re: [RFC PATCH 0/7] sched: cpufreq: Remove magic margins Message-ID: <20230912142821.GA22166@noisy.programming.kicks-ass.net> References: <20230827233203.1315953-1-qyousef@layalina.io> <20230906211850.zyvk6qtt6fvpxaf3@airbuntu> <20230907132631.GF10955@noisy.programming.kicks-ass.net> <8919ed14-8d19-d964-2278-3303a5bda8ee@arm.com> <20230907142923.GJ10955@noisy.programming.kicks-ass.net> <20230907201609.GC14243@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 12, 2023 at 12:51:52PM +0100, Lukasz Luba wrote: > You can see the util signal of that 'CrRendererMain' task and those > utilization drops in time, which I was referring to. When the util > drops below some threshold, the task might 'fit' into smaller CPU, > which could be prevented automatically byt maintaining the util est > for longer (but not for all). Right, so right at those util_est dips it has some small activations. It's like a poll loop or something instead of a full block waiting for things to happen. And yeah, that'll destroy util_est in a hurry :/ > I do like your idea that Util EST might be per-task. I'm going to > check this, because that might help to get rid of the overutilized state > which is probably because small tasks are also 'bigger' for longer. > > If this util est have chance to fly upstream, I could send an RFC if > you don't mind. The biggest stumbling block I see is the user interface; some generic QoS hints based thing that allows us to do random things -- like tune the above might do, dunno.