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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 834D9C433DB for ; Wed, 17 Feb 2021 11:38:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 557B764E2E for ; Wed, 17 Feb 2021 11:38:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232458AbhBQLiF (ORCPT ); Wed, 17 Feb 2021 06:38:05 -0500 Received: from foss.arm.com ([217.140.110.172]:56714 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231380AbhBQLbG (ORCPT ); Wed, 17 Feb 2021 06:31:06 -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 7203931B; Wed, 17 Feb 2021 03:30:13 -0800 (PST) Received: from localhost (unknown [10.1.195.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 043473F73B; Wed, 17 Feb 2021 03:30:12 -0800 (PST) Date: Wed, 17 Feb 2021 11:30:11 +0000 From: Ionela Voinescu To: Viresh Kumar Cc: Rafael Wysocki , Catalin Marinas , Will Deacon , Vincent Guittot , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, Sudeep Holla , Greg Kroah-Hartman Subject: Re: [PATCH V3 1/2] topology: Allow multiple entities to provide sched_freq_tick() callback Message-ID: <20210217113011.GA22176@arm.com> References: <20210203114521.GA6380@arm.com> <20210205091424.3od3tme3f7mh7ebp@vireshk-i7> <20210217002422.GA17422@arm.com> <20210217042558.o4anjdkayzgqny55@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210217042558.o4anjdkayzgqny55@vireshk-i7> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi, Replying this first as it's going to be relevant below: > Just out of curiosity, what exactly did you test and what was the setup ? :) I tested it on: - Juno R0 (CPUs [0, 3-5] are littles, CPUs [1-2] are bigs) + PMUs faking AMUs + userspace/schedutil + + cpufreq-FIE/!cpufreq-FIE + DT This testing did not yet cover patch 2/2. My checklist shows: - system invariance status correct - passed - scale factor correct (userspace cpufreq governor) - passed - arch_set_freq_scale bypassed - passed - partial "AMUs" support - failed (see below) - EAS enabling - passed I don't have an automated process for this as many test cases involve kernel source changes. In time I will automate all of these and possibly cover all scenarios with FVP (fast models) testing, but for now human error is possible :). On Wednesday 17 Feb 2021 at 09:55:58 (+0530), Viresh Kumar wrote: > On 17-02-21, 00:24, Ionela Voinescu wrote: > > I think it could be merged in patch 1/2 as it's part of enabling the use > > of multiple sources of information for FIE. Up to you! > > Sure. > > > > static void amu_fie_setup(const struct cpumask *cpus) > > > { > > > - bool invariant; > > > int cpu; > > > > > > /* We are already set since the last insmod of cpufreq driver */ > > > @@ -257,25 +256,10 @@ static void amu_fie_setup(const struct cpumask *cpus) > > > > > > cpumask_or(amu_fie_cpus, amu_fie_cpus, cpus); > > > > > > - invariant = topology_scale_freq_invariant(); > > > - > > > - /* We aren't fully invariant yet */ > > > - if (!invariant && !cpumask_equal(amu_fie_cpus, cpu_present_mask)) > > > - return; > > > - > > > > You still need these checks, otherwise you could end up with only part > > of the CPUs setting a scale factor, when only part of the CPUs support > > AMUs and there is no cpufreq support for FIE. > > Both supports_scale_freq_counters() and topology_scale_freq_invariant() take > care of this now and they will keep reporting the system as invariant until the > time all the CPUs have counters (in absence of cpufreq). > Correct! > The topology_set_scale_freq_source() API is supposed to be called multiple > times, probably once for each policy and so I don't see a need of these checks > anymore. > The problem is not topology_scale_freq_invariant() but whether a scale factor is set for some CPUs. Scenario (test system above): - "AMUs" are only supported for [1-2], - cpufreq_supports_freq_invariance() -> false What should happen: - topology_scale_freq_invariant() -> false (passed) - all CPUs should have their freq_scale unmodified (1024) - (failed) because only 2 out of 6 CPUs have a method of setting a scale factor What does happen: - arch_set_freq_tick() -> topology_set_freq_tick() will set a scale factor for [1-2] based on AMUs. This should not happen. We will end up with invariant signals for bigs and signals that are not freq invariant for littles. Ionela. > > Small(ish) optimisation at the beginning of this function: > > > > if (cpumask_empty(&scale_freq_counters_mask)) > > scale_freq_invariant = topology_scale_freq_invariant(); > > > > This will save you a call to rebuild_sched_domains_energy(), which is > > quite expensive, when cpufreq supports FIE and we also have counters. > > Good Point. > > > After comments addressed, > > > > Reviewed-by: Ionela Voinescu > > Thanks. > > > Tested-by: Ionela Voinescu > > > -- > viresh