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 D0804C33CAA for ; Tue, 21 Jan 2020 09:10:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC2BA24125 for ; Tue, 21 Jan 2020 09:10:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729142AbgAUJK0 (ORCPT ); Tue, 21 Jan 2020 04:10:26 -0500 Received: from foss.arm.com ([217.140.110.172]:39822 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727969AbgAUJKZ (ORCPT ); Tue, 21 Jan 2020 04:10:25 -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 707D31FB; Tue, 21 Jan 2020 01:10:24 -0800 (PST) Received: from [192.168.0.7] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id ED5023F6C4; Tue, 21 Jan 2020 01:10:17 -0800 (PST) Subject: Re: [PATCH 1/4] PM / EM: and devices to Energy Model To: Lukasz Luba , Quentin Perret Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-imx@nxp.com, Morten.Rasmussen@arm.com, Chris.Redpath@arm.com, ionela.voinescu@arm.com, javi.merino@arm.com, cw00.choi@samsung.com, b.zolnierkie@samsung.com, rjw@rjwysocki.net, sudeep.holla@arm.com, viresh.kumar@linaro.org, nm@ti.com, sboyd@kernel.org, rui.zhang@intel.com, amit.kucheria@verdurent.com, daniel.lezcano@linaro.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com, kernel@pengutronix.de, khilman@kernel.org, agross@kernel.org, bjorn.andersson@linaro.org, robh@kernel.org, matthias.bgg@gmail.com, steven.price@arm.com, tomeu.vizoso@collabora.com, alyssa.rosenzweig@collabora.com, airlied@linux.ie, daniel@ffwll.ch, kernel-team@android.com References: <20200116152032.11301-1-lukasz.luba@arm.com> <20200116152032.11301-2-lukasz.luba@arm.com> <20200117105437.GA211774@google.com> <40587d98-0e8d-cbac-dbf5-d26501d47a8c@arm.com> <20200120150918.GA164543@google.com> <8332c4ac-2a7d-1e2d-76e9-7c979a666257@arm.com> From: Dietmar Eggemann Message-ID: Date: Tue, 21 Jan 2020 10:10:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/01/2020 19:38, Lukasz Luba wrote: > > > On 1/20/20 6:27 PM, Dietmar Eggemann wrote: >> On 20/01/2020 16:09, Quentin Perret wrote: >>> Hey Lukasz, >>> >>> On Monday 20 Jan 2020 at 14:52:07 (+0000), Lukasz Luba wrote: >>>> On 1/17/20 10:54 AM, Quentin Perret wrote: [...] >> It's true that we need the policy->cpus cpumask only for cpu devices and >> we have it available when we call em_register_perf_domain() >> [scmi-cpufreq.c driver] or the OPP wrapper dev_pm_opp_of_register_em() >> [e.g. cpufreq-dt.c driver]. >> >> And we shouldn't make EM code dependent on OPP. >> >> But can't we add 'struct cpumask *mask' as an additional argument to >> both which can be set to NULL for (devfreq) devices? >> >> We can check in em_register_perf_domain() that we got a valid cpumask >> for a cpu device and ignore it for (devfreq) devices. >> > > I think we could avoid this additional argument 'cpumask'. I have > checked the cpufreq_cpu_get function, which should do be good for this: > > ---------->8------------------------- > static int _get_sharing_cpus(struct device *cpu_dev, struct cpumask *span) > { >         struct cpufreq_policy *policy; > >         policy = cpufreq_cpu_get(cpu_dev->id); >         if (policy) { >                 cpumask_copy(span, policy->cpus); >                 cpufreq_cpu_put(policy); >                 return 0; >         } else { >                 return -EINVAL; >         } > } > --------------------------8<------------------------------- > > It would be a replacement for: > ret = dev_pm_opp_get_sharing_cpus(dev, span); True. But then we hard-code that a CPU device performance domain can only be a frequency domain (which is true today). The task scheduler (build_perf_domains()) and thermal are already using cpufreq_cpu_get() to access the cpufreq policy. Now the EM framework would too for CPU devices. I assume that could work with a couple of adaptations in Documentation/power/energy-model.rst. BTW, there is a similar interface cpufreq_get_policy() in cpufreq.c which is used less often?