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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 65045C433E0 for ; Fri, 5 Jun 2020 10:45:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 450C32075B for ; Fri, 5 Jun 2020 10:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726744AbgFEKpZ (ORCPT ); Fri, 5 Jun 2020 06:45:25 -0400 Received: from foss.arm.com ([217.140.110.172]:53494 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726465AbgFEKpX (ORCPT ); Fri, 5 Jun 2020 06:45:23 -0400 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 EBB442B; Fri, 5 Jun 2020 03:45:22 -0700 (PDT) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3C1303F52E; Fri, 5 Jun 2020 03:45:20 -0700 (PDT) Date: Fri, 5 Jun 2020 11:45:17 +0100 From: Qais Yousef To: Vincent Guittot Cc: Mel Gorman , Patrick Bellasi , Dietmar Eggemann , Peter Zijlstra , Ingo Molnar , Randy Dunlap , Jonathan Corbet , Juri Lelli , Steven Rostedt , Ben Segall , Luis Chamberlain , Kees Cook , Iurii Zaikin , Quentin Perret , Valentin Schneider , Pavan Kondeti , linux-doc@vger.kernel.org, linux-kernel , linux-fs Subject: Re: [PATCH 1/2] sched/uclamp: Add a new sysctl to control RT default boost value Message-ID: <20200605104517.r65dqhzavnnrnfb2@e107158-lin.cambridge.arm.com> References: <20200528132327.GB706460@hirez.programming.kicks-ass.net> <20200528155800.yjrmx3hj72xreryh@e107158-lin.cambridge.arm.com> <20200528161112.GI2483@worktop.programming.kicks-ass.net> <20200529100806.GA3070@suse.de> <87v9k84knx.derkling@matbug.net> <20200603101022.GG3070@suse.de> <20200603165200.v2ypeagziht7kxdw@e107158-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/04/20 14:14, Vincent Guittot wrote: > I have tried your patch and I don't see any difference compared to > previous tests. Let me give you more details of my setup: > I create 3 levels of cgroups and usually run the tests in the 4 levels > (which includes root). The result above are for the root level > > But I see a difference at other levels: > > root level 1 level 2 level 3 > > /w patch uclamp disable 50097 46615 43806 41078 > tip uclamp enable 48706(-2.78%) 45583(-2.21%) 42851(-2.18%) > 40313(-1.86%) > /w patch uclamp enable 48882(-2.43%) 45774(-1.80%) 43108(-1.59%) > 40667(-1.00%) > > Whereas tip with uclamp stays around 2% behind tip without uclamp, the > diff of uclamp with your patch tends to decrease when we increase the > number of level Thanks for the extra info. Let me try this. If you can run perf and verify that you see activate/deactivate_task showing up as overhead I'd appreciate it. Just to confirm that indeed what we're seeing here are symptoms of the same problem Mel is seeing. > Beside this, that's also interesting to notice the ~6% of perf impact > between each level for the same image Interesting indeed. Thanks -- Qais Yousef