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=-2.2 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 C3E11C3F68F for ; Tue, 24 Dec 2019 11:08:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A441F20706 for ; Tue, 24 Dec 2019 11:08:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726245AbfLXLIk (ORCPT ); Tue, 24 Dec 2019 06:08:40 -0500 Received: from foss.arm.com ([217.140.110.172]:51084 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726091AbfLXLIk (ORCPT ); Tue, 24 Dec 2019 06:08:40 -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 C14C31FB; Tue, 24 Dec 2019 03:08:39 -0800 (PST) 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 56E813F534; Tue, 24 Dec 2019 03:08:37 -0800 (PST) Date: Tue, 24 Dec 2019 11:08:35 +0000 From: Qais Yousef To: Doug Smythies Cc: 'Giovanni Gherdovich' , x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, 'Mel Gorman' , 'Matt Fleming' , 'Viresh Kumar' , 'Juri Lelli' , 'Paul Turner' , 'Peter Zijlstra' , 'Vincent Guittot' , 'Quentin Perret' , 'Dietmar Eggemann' , 'Srinivas Pandruvada' , 'Thomas Gleixner' , 'Ingo Molnar' , 'Borislav Petkov' , 'Len Brown' , "'Rafael J . Wysocki'" Subject: Re: [PATCH v4 1/6] x86,sched: Add support for frequency invariance Message-ID: <20191224110834.rgibtqm6dr6kmu5y@e107158-lin.cambridge.arm.com> References: <1574781600.7677.2.camel@suse.cz> <001d01d5a4f4$d96b21b0$8c416510$@net> <003d01d5a63d$f6ab3950$e401abf0$@net> <20191219104813.6fr34qavpaplecoz@e107158-lin> <000701d5b965$361b6c60$a2524520$@net> <20191223140743.o2wfoqtf56g4yrk5@e107158-lin.cambridge.arm.com> <20191223144043.ticfxfgbolsqk74i@e107158-lin.cambridge.arm.com> <000301d5b9ae$cd8f5b30$68ae1190$@net> <20191223191014.g7lnxafuadwtcqub@e107158-lin.cambridge.arm.com> <000401d5b9f7$cf3782c0$6da68840$@net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <000401d5b9f7$cf3782c0$6da68840$@net> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/23/19 17:16, Doug Smythies wrote: > Yes, it fixes the schedutil governor behaving like the performance governor > problem on my i7-2600K test system. > > I re-ran the tests several times, and re-booted back to the stock (problem) > kernel to verify incorrect schedutil governor performance (i.e. I toggled > back and forth, 2 times for each of 2 kernels, tests 1 and 2, total 8 tests). > Kernel 5.5-rc2: 4 tests FAILED (as expected). > Kernel 5.5-rc2 + this patch: 4 tests PASSED. Great! Thanks for testing it, I'll send a proper patch shortly. > > Accidentally tested: > Kernel 5.5-rc2 + this patch + command line "cgroup_no_v1=all": 1 test PASS. I think this cgroup_no_v1 is a happy accident. It has nothing to do with the fault, but for your case maybe helped observing things in a better way. FWIW, I reproduced the issue on Juno Arm64 using Debian and Buildroot rootfs. What is actually required to trigger the bug is to create a cpu controller and add all system tasks to it to create some noise - which Ubuntu and Debian do by default at boot time. In Buildroot when I did that manually I could see the frequency going to max most of the time. I'll add away to test this scenario. Thanks for your detailed report. Happy holidays! -- Qais Yousef