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=0.7 required=3.0 tests=BODY_8BITS, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 925E8C5CFC1 for ; Tue, 19 Jun 2018 13:06:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 589502083D for ; Tue, 19 Jun 2018 13:06:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 589502083D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966468AbeFSNG2 (ORCPT ); Tue, 19 Jun 2018 09:06:28 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:49866 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965740AbeFSNG0 (ORCPT ); Tue, 19 Jun 2018 09:06:26 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1402A80D; Tue, 19 Jun 2018 06:06:26 -0700 (PDT) Received: from e108498-lin.cambridge.arm.com (e108498-lin.cambridge.arm.com [10.1.211.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1E0783F557; Tue, 19 Jun 2018 06:06:21 -0700 (PDT) Date: Tue, 19 Jun 2018 14:06:20 +0100 From: Quentin Perret To: Peter Zijlstra Cc: rjw@rjwysocki.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, mingo@redhat.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, chris.redpath@arm.com, patrick.bellasi@arm.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, thara.gopinath@linaro.org, viresh.kumar@linaro.org, tkjos@google.com, joelaf@google.com, smuckle@google.com, adharmap@quicinc.com, skannan@quicinc.com, pkondeti@codeaurora.org, juri.lelli@redhat.com, edubezval@gmail.com, srinivas.pandruvada@linux.intel.com, currojerez@riseup.net, javi.merino@kernel.org Subject: Re: [RFC PATCH v3 04/10] PM / EM: Expose the Energy Model in sysfs Message-ID: <20180619130620.GZ17720@e108498-lin.cambridge.arm.com> References: <20180521142505.6522-1-quentin.perret@arm.com> <20180521142505.6522-5-quentin.perret@arm.com> <20180619121643.GR2458@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180619121643.GR2458@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 19 Jun 2018 at 14:16:43 (+0200), Peter Zijlstra wrote: > On Mon, May 21, 2018 at 03:24:59PM +0100, Quentin Perret wrote: > > This exposes the Energy Model (read-only) of all frequency domains in > > sysfs for convenience. To do so, a parent kobject is added to the CPU > > subsystem under the umbrella of which a kobject for each frequency > > domain is attached. > > > > The resulting hierarchy is as follows for a platform with two frequency > > domains for example: > > > > /sys/devices/system/cpu/energy_model > > ├── fd0 > > │   ├── capacity > > │   ├── cpus > > │   ├── frequency > > │   └── power > > └── fd4 > > ├── capacity > > ├── cpus > > ├── frequency > > └── power > > > > Given that each FD can have multiple {freq,power} tuples and sysfs has a > one value per file policy, how does this work? This is meant to look a little bit like the sysfs entries of CPUFreq policies, so you get something like this: $ cat /sys/devices/system/cpu/energy_model/fd0/capacity 133 250 351 428 462 $ cat /sys/devices/system/cpu/energy_model/fd0/frequency 533000 999000 1402000 1709000 1844000 $ cat /sys/devices/system/cpu/energy_model/fd0/power 28 70 124 187 245 $ cat /sys/devices/system/cpu/energy_model/fd0/cpus 0-3 For example, CPUFreq exposes available governors and frequencies as: $ cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors conservative ondemand userspace powersave performance schedutil $ cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies 533000 999000 1402000 1709000 1844000