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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 05F37C4363A for ; Fri, 30 Oct 2020 12:41:31 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7F7EE2071A for ; Fri, 30 Oct 2020 12:41:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Yk75Jck2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F7EE2071A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=8jNtcsoyRD5bXZBntckP3yuKIbGi9BX+0uigfQ6Yfn4=; b=Yk75Jck28g6wpdq4QiAI6k+oj f+usQLfDb30N2ue2aFXLBkO75llHNZLlX68M1rS1EgIikyawXNCB3HVvnIei54njDgx8+VzGq3qAQ CvqNKOMh04L4iykFvcm3FlOXXF4D+LlCNeTUSEeDVd3nL/pvQ3mWfsq13EfZPuMC+mGGZvf08rwM3 ZIy81q9y5hd0PjiRXVb192mshkAQtL1A5KadRL9K9THHEvBOz76zorAj3pgEQzDXV5eN6IoOFNMIQ svxx9BVkBEuWavhjQF8zHA3ID6vB59U9R3no0wKcTK/7aNYkK/mYYNbWR3yTLQcFaQauoliMGk4Cc iqJNDvmRw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYTiC-0003IO-Em; Fri, 30 Oct 2020 12:40:56 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYTi9-0003I0-K1 for linux-arm-kernel@lists.infradead.org; Fri, 30 Oct 2020 12:40:54 +0000 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 6FCFA1063; Fri, 30 Oct 2020 05:40:47 -0700 (PDT) Received: from [10.57.13.192] (unknown [10.57.13.192]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7143C3F68F; Fri, 30 Oct 2020 05:40:44 -0700 (PDT) Subject: Re: [PATCH 0/4] Add sustainable OPP concept To: Viresh Kumar References: <20201028140847.1018-1-lukasz.luba@arm.com> <20201029074057.6ugmwyzna52x3oli@vireshk-i7> <20201029075356.rruej6jlerhfa4oy@vireshk-i7> <228fa1b3-bbd3-6941-fd4b-06581016d839@arm.com> <20201030082937.xgjmko2ohwhkt6f5@vireshk-i7> <20201030095248.abej6h5wphud2ihb@vireshk-i7> <757fe3b1-745f-2656-fe21-c7b39f123a25@arm.com> <20201030111751.i7zdsi7ruzmnyxk6@vireshk-i7> From: Lukasz Luba Message-ID: <468065c6-d604-5691-cddf-3eca20035bba@arm.com> Date: Fri, 30 Oct 2020 12:40:42 +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: <20201030111751.i7zdsi7ruzmnyxk6@vireshk-i7> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201030_084053_770144_D0E081C7 X-CRM114-Status: GOOD ( 29.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: nm@ti.com, devicetree@vger.kernel.org, daniel.lezcano@linaro.org, vincent.guittot@linaro.org, linux-pm@vger.kernel.org, sboyd@kernel.org, vireshk@kernel.org, rafael@kernel.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, sudeep.holla@arm.com, Dietmar.Eggemann@arm.com, linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/30/20 11:17 AM, Viresh Kumar wrote: > On 30-10-20, 10:56, Lukasz Luba wrote: >> IPA tries to do that, even dynamically when e.g. GPU is supper busy >> in 3D games (~2000W) or almost idle showing 2D home screen. >> It tries to find highest 'sustainable' frequencies for the devices, >> at that various workloads and temp. But it needs some coefficients to >> start, which have big impact on the algorithm. It could slow down IPA a >> lot, when those coefficients are calculated based on lowest OPPs. > > I see. So when you say it slows down IPA, what does that really mean ? > IPA isn't performing that accurately during the initial period of > booting (any time estimate here) ? Does it work fine after a time > duration? Or will it suffer for ever ? The coefficients would stay 'forever', which determine the temp rising slope, until someone change them via sysfs (the: k_po, k_pu, k_i, sustainable_power). > > And maybe you shouldn't start with the lowest OPPs while you calculate > these coefficients dynamically ? Maybe start from the middle ? As the > sustainable OPP would be something there only or maybe a bit higher > only. But yeah, I don't have any idea about how those coefficients are > calculated so this idea can be simply ignored as well :) > >> My backup plan was to add a flag into EM em_perf_state, extend SCMI perf >> exposing the 'sustained_freq_khz' to scmi-cpufreq, which would set that >> field after registering EM. IPA depends on EM, so should be OK. > > I think at this point (considering the limited number of users (only > IPA) and providers (only SCMI)), it would be better that way only > instead of updating the OPP framework. Of course we can revisit that > if we ever feel that we need a better placeholder for it. OK, sounds good. > >>> So only SCMI based platforms will be able to use this stuff ? That's >>> very limited, isn't it ? I think we should still try to make it better >>> for everyone by making the software smarter. It has so much data, the >>> OPPs, the power it will consume (based on microvolt property?), the >>> heat we produce from that (from thermal framework), etc. Perhaps >>> building this information continuously at runtime based on when and >>> how we hit the trip points ? So we know which is the right frequency >>> where we can refrain from hitting the trip points. >> >> IPA works in this way. > > Nice, that's what I thought as well but then got a bit confused with > your patchset. > >>> But may be I am asking too much :( >>> >> >> When you asked for user of this, I gave you instantly. This is one is >> more difficult. I am still not there with IPA tests in LISA. I have some >> out-of-tree kernel driver for testing, which also need polishing before >> can be used with LISA. Then proper workloads with results processing. >> EM for devfreq cooling devices. Then decent 'hot' board running >> preferably mainline kernel. >> What you requested is on my list, but it needs more work, which >> won't be ready over night. > > I can understand what you are trying to do here. And this surely > requires a lot of effort. > Thank you Viresh for your opinion. I will take the EM approach, please ignore this patch set. Regards, Lukasz _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel