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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 1A08DC4332B for ; Wed, 3 Feb 2021 15:17:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCD5864E4B for ; Wed, 3 Feb 2021 15:17:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234420AbhBCPR0 (ORCPT ); Wed, 3 Feb 2021 10:17:26 -0500 Received: from foss.arm.com ([217.140.110.172]:41792 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233818AbhBCPOu (ORCPT ); Wed, 3 Feb 2021 10:14:50 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 47FBE11FB; Wed, 3 Feb 2021 07:14:04 -0800 (PST) Received: from e107158-lin (e107158-lin.cambridge.arm.com [10.1.194.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E9D323F73B; Wed, 3 Feb 2021 07:14:02 -0800 (PST) Date: Wed, 3 Feb 2021 15:14:00 +0000 From: Qais Yousef To: Valentin Schneider Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Vincent Guittot , Dietmar Eggemann , Morten Rasmussen , Quentin Perret , Pavan Kondeti , Rik van Riel Subject: Re: [PATCH 0/8] sched/fair: misfit task load-balance tweaks Message-ID: <20210203151400.ommltjjyuok4yj5e@e107158-lin> References: <20210128183141.28097-1-valentin.schneider@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210128183141.28097-1-valentin.schneider@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/28/21 18:31, Valentin Schneider wrote: > Hi folks, > > Here is this year's series of misfit changes. On the menu: > > o Patch 1 is an independent active balance cleanup > o Patch 2 adds some more sched_asym_cpucapacity static branches > o Patch 3 introduces yet another margin for capacity to capacity > comparisons > o Patches 4-6 build on top of patch 3 and change capacity comparisons > throughout misfit load balancing > o Patches 7-8 fix some extra misfit issues I've been seeing on "real" > workloads. > > IMO the somewhat controversial bit is patch 3, because it attempts to solve > margin issues by... Adding another margin. This does solve issues on > existing platforms (e.g. Pixel4), but we'll be back to square one the day > some "clever" folks spin a platform with two different CPU capacities less than > 5% apart. One more margin is a cause of apprehension to me. But in this case I think it is the appropriate thing to do now. I can't think of a scenario where this could hurt. Thanks -- Qais Yousef