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=-5.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0B3ADC4727E for ; Tue, 6 Oct 2020 07:19:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2FF720760 for ; Tue, 6 Oct 2020 07:19:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="MzsarqGU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727229AbgJFHTP (ORCPT ); Tue, 6 Oct 2020 03:19:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54076 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727172AbgJFHTN (ORCPT ); Tue, 6 Oct 2020 03:19:13 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27463C061755 for ; Tue, 6 Oct 2020 00:19:13 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id o9so775240plx.10 for ; Tue, 06 Oct 2020 00:19:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=m2b+rmKRGPYGRHjXu3I4nFOGjf5oCG8gDODedqsY8HI=; b=MzsarqGUb28zUo1ZRQuRl2CQFRw++HYQ9UsKlDiioJRx4DDwqhZDVh8zkS5ZMaLDPN PuUv7/4fQPcMU4pTP8LgkCw7cXvG4Q7wMpcYZP1NRw5oFwk9avs29jXu6WJ7Kqpb3dEw E84b/Q8xEWKH54B99Wka5P9nno7+tj/P6JYT+sykdnSBV80ZOiZ5/Y2SSMr+KISzJyFC lsnZ4iPOniWwx5fMVAMlNJwUHCsFhvi4eOWqtdMmuUuYtXldriIAPaBJoOJqEX0nljck OurpuFskSQdMmkCc1oZiC+bdw4aFm2tydZEQQh3tvvSFD02Q6AqJuOZN5nGTssGzhquK Bk7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=m2b+rmKRGPYGRHjXu3I4nFOGjf5oCG8gDODedqsY8HI=; b=OACqYmySlYjfofTNW1fvL1C/aEBmnF7V/MYnjlnXb6RWeSdJIOgOwfAdYuZz88IWhb I7Sg4a7vPfzt50ikMernzqLja5FoaXdBKFSkCdAw8oOF58M99lSmMtyoi7Dk5ti8qCwF B2QLLTFgFEGZjMDGg8xMQvv30+j0zdE2Ln30R8VfmFLhrA9fMazhRbidCmGgUEWuTeEA 9yFsRr/xA7V5wpSjj2Ao0GPWl8WH1Teekj2FePUtZOymJ/cx4pfDdmwuDk6aeAcZ0Ut5 MVCK7mBk2dE7vfzhwrx8v0kC4j0C+nClzWAImh53caCni5yuswOU6cxd6DvWsm7n4Ep9 BjPQ== X-Gm-Message-State: AOAM533iyo8dE4Fx2MREV6PHsPC8C7Bl5wQNqIn09+dQVox89fnOB5pc J5ZKshTnkU2PkfSfmtnOyfnnpQ== X-Google-Smtp-Source: ABdhPJwDUUyCJoFXkW7uX+HT9mhqyp71hZG+SsLmVoqnODhfEK9QCzoSbQzGtxk5AUvOx2IO9tk/nQ== X-Received: by 2002:a17:90a:a595:: with SMTP id b21mr2943649pjq.95.1601968752689; Tue, 06 Oct 2020 00:19:12 -0700 (PDT) Received: from localhost ([122.181.54.133]) by smtp.gmail.com with ESMTPSA id j4sm2140975pfj.143.2020.10.06.00.19.10 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 06 Oct 2020 00:19:11 -0700 (PDT) Date: Tue, 6 Oct 2020 12:49:09 +0530 From: Viresh Kumar To: Nicola Mazzucato Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-pm@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, vireshk@kernel.org, robh+dt@kernel.org, daniel.lezcano@linaro.org, morten.rasmussen@arm.com, chris.redpath@arm.com Subject: Re: [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies Message-ID: <20201006071909.3cgz7i5v35dgnuzn@vireshk-i7> References: <20200924095347.32148-1-nicola.mazzucato@arm.com> <20200924095347.32148-3-nicola.mazzucato@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200924095347.32148-3-nicola.mazzucato@arm.com> User-Agent: NeoMutt/20180716-391-311a52 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24-09-20, 10:53, Nicola Mazzucato wrote: > I am seeking some feedback/comments on the following approach. > > Intro: > Info of performance depency for cpus will be beneficial for systems > where f/w description of the CPU performance control domain is different > from the clock domain, e.g. per-CPU control with multiple CPUs sharing > clock, and kernel OSPM s/w components need to take CPU performance > dependency into account. > Essentially these s/w components will have to be provided with > this information from dt and this RFC is presenting a possible way > to do so. I am not sure I understand what performance control mean here. Can you please elaborate a bit more on that ? For example, with current code and understanding, a cpufreq policy belongs to a group of CPUs which change their frequency together, which also mean that they change their performance level together and so I am not able to understand what's going on here. Sorry about that. What kind of hardware configuration doesn't work with this ? -- viresh