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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 2B6ADC83D20 for ; Mon, 16 Nov 2020 12:38:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E402320853 for ; Mon, 16 Nov 2020 12:38:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729420AbgKPLdU (ORCPT ); Mon, 16 Nov 2020 06:33:20 -0500 Received: from foss.arm.com ([217.140.110.172]:38220 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728921AbgKPLdT (ORCPT ); Mon, 16 Nov 2020 06:33:19 -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 EFF7C101E; Mon, 16 Nov 2020 03:33:18 -0800 (PST) Received: from [10.57.26.102] (unknown [10.57.26.102]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CB5D43F70D; Mon, 16 Nov 2020 03:33:15 -0800 (PST) Subject: Re: [PATCH v3 3/3] [RFC] CPUFreq: Add support for cpu-perf-dependencies To: Viresh Kumar Cc: Nicola Mazzucato , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, vireshk@kernel.org, robh+dt@kernel.org, sboyd@kernel.org, nm@ti.com, daniel.lezcano@linaro.org, morten.rasmussen@arm.com, chris.redpath@arm.com References: <20201102120115.29993-1-nicola.mazzucato@arm.com> <20201102120115.29993-4-nicola.mazzucato@arm.com> <20201106092020.za3oxg7gutzc3y2b@vireshk-i7> <0a334a73-45ef-58ff-7dfd-9df6f4ff290a@arm.com> <20201106105514.bhtdklyhn7goml64@vireshk-i7> <7f73bcd6-0f06-4ef0-7f02-0751e6c4d94b@arm.com> <20201109065742.22czfgyjhsjmkytf@vireshk-i7> From: Lukasz Luba Message-ID: <2fa8a5c0-f66d-34bc-7f1c-8462e7532e0a@arm.com> Date: Mon, 16 Nov 2020 11:33:13 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20201109065742.22czfgyjhsjmkytf@vireshk-i7> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/9/20 6:57 AM, Viresh Kumar wrote: > On 06-11-20, 11:14, Lukasz Luba wrote: >> I also had similar doubts, because if we make frequency requests >> independently for each CPU, why not having N cooling devs, which >> will set independently QoS max freq for them... >> >> What convinced me: >> EAS and FIE would know the 'real' frequency of the cluster, IPA >> can use it also and have only one cooling device per cluster. >> >> We would like to keep this old style 'one cooling device per cpuset'. >> I don't have strong opinion and if it would appear that there are >> some errors in freq estimation for cluster, then maybe it does make >> more sense to have cdev per CPU... > > Let me rephrase my question. What is it that doesn't work _correctly_ > with cdev per cpufreq policy in your case? What doesn't work well if > the thermal stuff keeps looking at only the related_cpus thing and not > the cpu-perf-dependencies thing? > We don't have a platform which would be this per-cpu freq request, yet. Thus it's hard to answer your question. The EAS would work in 'old style' - cluster mode. I don't know how IPA would work on such HW and SW configuration. To figure this out I need a real platform.