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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 9920EC10F07 for ; Tue, 19 Jan 2021 18:28:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F21D20706 for ; Tue, 19 Jan 2021 18:28:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389414AbhASQ5f (ORCPT ); Tue, 19 Jan 2021 11:57:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391123AbhASQ4D (ORCPT ); Tue, 19 Jan 2021 11:56:03 -0500 Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4CA8C061575 for ; Tue, 19 Jan 2021 08:55:20 -0800 (PST) Received: by mail-wm1-x32d.google.com with SMTP id j18so410471wmi.3 for ; Tue, 19 Jan 2021 08:55:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=M1s/++mXdMLvNe4dZQ7XRaGkTkWJbV1fdaKKOWF5MxU=; b=jRjZENiS0Iv14+JXtBpPK7jm3rowqG23vo+Q5o9q2+RTDGdVS6iyH1ehkZh8OMn49S o+N/c7in+6FOaFhN24NuRlbzZHFdF/OEIdkP+E3Virz7ry6DhLm7c2AwUdGWjbwGJD+b 1uf8bJDy68fshA63n4Q8psN8CCP18zbvzJMEIRvc2P8u5wudsBUDaolEGNnFnZhfHW1t vUOdnqDKP/0a5Ne2ooLsGo+6x0DBXkQNLGdN7w/MRjtHPaPwcONuXJ8QlJm6KxCxNxRa wYjvQF8Tr8qMl4vJxVUw+bGSN5RqiHxLOPN4Vkd2vQjRU9/wG+fNFfoissmsAt/zdt7V v7Fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=M1s/++mXdMLvNe4dZQ7XRaGkTkWJbV1fdaKKOWF5MxU=; b=M3dRTGuEcTJQpPP4foCnMFka2DukAYiSFOFBaRIROwSK4uFyI89bZAKPcqPlVPMM4j ZzqNinLxN5V5tRUz+O3ifbPp8pgoBkCimsRqWtDGNCnAZ630WvabPAq+6G+lKxWFvL+R 01Xq5M2xopIR7psef5rW+LGwCFshRvIZ9FLJxcpq9f91UxHnNovgJ0gsU+Fg7OYFJudm WKHnet4rU1pXyc1NQZaP75HahMkCIFn9W9xawHzoFSyMf2l9zvu56o1H52rUG4vNGsZl Q82mQvRbkshh+MwZ0Jn9HGX1c7sSqkriALLt0Y/GFU1Pw5CMvvhX1zGCb6cBDG7thNwf PQGA== X-Gm-Message-State: AOAM5314B8oMIrWbJti6Lwqqyi518gt6/gKo4IG28YoP96WPXNT8ws1Y LV+fs7dHLkJ09JxRRIFDrjSqKQ== X-Google-Smtp-Source: ABdhPJyiX9CbGDRV+ypQ878lBxhRymKF2dIL9gS/39sPat84wAwCi9YqT+lmDbua2YB6A8lVe4+NMg== X-Received: by 2002:a1c:a501:: with SMTP id o1mr500863wme.21.1611075319349; Tue, 19 Jan 2021 08:55:19 -0800 (PST) Received: from google.com (230.69.233.35.bc.googleusercontent.com. [35.233.69.230]) by smtp.gmail.com with ESMTPSA id g194sm5338792wme.39.2021.01.19.08.55.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Jan 2021 08:55:18 -0800 (PST) Date: Tue, 19 Jan 2021 16:55:16 +0000 From: Quentin Perret To: Qais Yousef Cc: "Peter Zijlstra (Intel)" , Dietmar Eggemann , Vincent Guittot , linux-kernel@vger.kernel.org, Valentin Schneider , Morten Rasmussen Subject: Re: [PATCH] sched/eas: Don't update misfit status if the task is pinned Message-ID: References: <20210119120755.2425264-1-qais.yousef@arm.com> <20210119164027.drfpmrol3xhf4ckc@e107158-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210119164027.drfpmrol3xhf4ckc@e107158-lin> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 19 Jan 2021 at 16:40:27 (+0000), Qais Yousef wrote: > On 01/19/21 15:35, Quentin Perret wrote: > > Do you mean failing the sched_setaffinity syscall if e.g. the task > > has a min clamp that is higher than the capacity of the CPUs to which it > > will be pinned? If so, I'm not sure if we really want that. > > No. In Android for instance, I'm worried a background task affined to little > cores that has a utilization > capacity_of(little) will trigger the same > problem. It'll be affined to more than just 1 cpu, but none of the little cpus > will actually fit. > > Makes sense? Now yes. I agree this may be a real problem, but capacity_of() very much is a per-CPU thing, because of RT pressure and such, and that is not a static thing by any mean. So, even if the task doesn't fit on any CPU _now_ we might still want to mark it misfit, just so it can be picked up by a potential idle balance on another CPU later on. Maybe capacity_orig_of would be preferable? Thanks, Quentin