From patchwork Sat Oct 3 13:19:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 286859 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=-9.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 CF4A7C4727E for ; Sat, 3 Oct 2020 13:19:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D64D207FF for ; Sat, 3 Oct 2020 13:19:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZGXtAxNj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725812AbgJCNT4 (ORCPT ); Sat, 3 Oct 2020 09:19:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:31843 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbgJCNTx (ORCPT ); Sat, 3 Oct 2020 09:19:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601731191; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PwMPMobhzodd3LpTbKx7ncPlyXiWAhBwmXqsIKHjwg4=; b=ZGXtAxNj2xcOl+K3DSqG/wl8ie0vqsmrbHKNDcVrtxYHVTQyPyddGhMb222bLf1tQ97ExJ L4dcUHNeZuueQ8uwcL0lv9G5SJR3rE76QBHm3Qq4Nf3LnAvUuJ4M0ci7Axk626nFU1yqAV H0FIeXehZYVtGelDy0V1tMuiCNv5gJA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-312-7_qOyy28MqCKlucBrvrcHg-1; Sat, 03 Oct 2020 09:19:47 -0400 X-MC-Unique: 7_qOyy28MqCKlucBrvrcHg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AEE2D801ADE; Sat, 3 Oct 2020 13:19:45 +0000 (UTC) Received: from x1.localdomain.com (ovpn-112-65.ams2.redhat.com [10.36.112.65]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1EEFF73677; Sat, 3 Oct 2020 13:19:42 +0000 (UTC) From: Hans de Goede To: Darren Hart , Andy Shevchenko , Mark Gross Cc: Hans de Goede , Mario Limonciello , Mark Pearson , Elia Devito , Bastien Nocera , Benjamin Berg , linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Mark Pearson Subject: [RFC] Documentation: Add documentation for new performance_profile sysfs class Date: Sat, 3 Oct 2020 15:19:38 +0200 Message-Id: <20201003131938.9426-2-hdegoede@redhat.com> In-Reply-To: <20201003131938.9426-1-hdegoede@redhat.com> References: <20201003131938.9426-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On modern systems CPU/GPU/... performance is often dynamically configurable in the form of e.g. variable clock-speeds and TPD. The performance is often automatically adjusted to the load by some automatic-mechanism (which may very well live outside the kernel). These auto performance-adjustment mechanisms often can be configured with one of several performance-profiles, with either a bias towards low-power consumption (and cool and quiet) or towards performance (and higher power consumption and thermals). Introduce a new performance_profile class/sysfs API which offers a generic API for selecting the performance-profile of these automatic-mechanisms. Cc: Mark Pearson Cc: Elia Devito Cc: Bastien Nocera Cc: Benjamin Berg Cc: linux-pm@vger.kernel.org Cc: linux-acpi@vger.kernel.org Signed-off-by: Hans de Goede --- .../testing/sysfs-class-performance_profile | 104 ++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-performance_profile diff --git a/Documentation/ABI/testing/sysfs-class-performance_profile b/Documentation/ABI/testing/sysfs-class-performance_profile new file mode 100644 index 000000000000..9c67cae39600 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-performance_profile @@ -0,0 +1,104 @@ +Performance-profile selection (e.g. /sys/class/performance_profile/thinkpad_acpi/) + +On modern systems CPU/GPU/... performance is often dynamically configurable +in the form of e.g. variable clock-speeds and TPD. The performance is often +automatically adjusted to the load by some automatic-mechanism (which may +very well live outside the kernel). + +These auto performance-adjustment mechanisms often can be configured with +one of several performance-profiles, with either a bias towards low-power +consumption (and cool and quiet) or towards performance (and higher power +consumption and thermals). + +The purpose of the performance_profile class is to offer a generic sysfs +API for selecting the performance-profile of these automatic-mechanisms. + +Note that this API is only for selecting the performance-profile, it is +NOT a goal of this API to allow monitoring the resulting performance +characteristics. Monitoring performance is best done with device/vendor +specific tools such as e.g. turbostat. + +Specifically when selecting a high-performance profile the actual achieved +performance may be limited by various factors such as: the heat generated by +other components, room temperature, free air flow at the bottom of a laptop, +etc. It is explicitly NOT a goal of this API to let userspace know about +any sub-optimal conditions which are impeding reaching the requested +performance level. + +Since numbers are a rather meaningless way to describe performance-profiles +this API uses strings to describe the various profiles. To make sure that +userspace gets a consistent experience when using this API this API document +defines a fixed set of profile-names. Drivers *must* map their internal +profile representation/names onto this fixed set. + +If for some reason there is no good match when mapping then a new profile-name +may be added. Drivers which wish to introduce new profile-names must: +1. Have very good reasons to do so. +2. Add the new profile-name to this document, so that future drivers which also + have a similar problem can use the same new. Usually new profile-names will + be added to the "extra profile-names" section of this document. But in some + cases the set of standard profile-names may be extended. + +What: /sys/class/performance_profile//available_profiles +Date: October 2020 +Contact: Hans de Goede +Description: + Reading this file gives a space separated list of profiles + supported for this device. + + Drivers must use the following standard profile-names whenever + possible: + + low-power: Emphasises low power consumption + (and also cool and quiet) + balanced-low-power: Balances between low power consumption + and performance with a slight bias + towards low power + balanced: Balance between low power consumption + and performance + balanced-performance: Balances between performance and low + power consumption with a slight bias + towards performance + performance: Emphasises performance (and may lead to + higher temperatures and fan speeds) + + Userspace may expect drivers to offer at least several of these + standard profile-names! If none of the above are a good match + for some of the drivers profiles, then drivers may use one of + these extra profile-names: + + +What: /sys/class/performance_profile//current_profile +Date: October 2020 +Contact: Hans de Goede +Description: + Reading this file gives the current selected profile for this + device. Writing this file with one of the strings from + available_profiles changes the profile to the new value. + + Reading this file may also return "custom". This is intended for + drivers which have and export multiple knobs influencing + performance. Such drivers may very well still want to offer a + set of profiles for easy of use and to be able to offer a + consistent standard API (this API) to userspace for configuring + their performance. The "custom" value is intended for when a + user has directly configured the knobs (through e.g. some + advanced control-panel for a GPU) and the knob values do not + match any of the presets represented by the + performance-profiles. In this case writing this file will + override the modifications and restore the selected presets. + +What: /sys/class/performance_profile//type +Date: October 2020 +Contact: Hans de Goede +Description: + Performance-profiles may be system-wide, or for a specific + device (e.g. CPU / GPU). System-wide profiles are typically + used on devices where where a single cooling solution is + shared between all components, such as laptops and NUCs. + + Reading this file indicates the type of the device for which + the thermal-profile is being configured. + + Valid values: "system" + Reserved for future use values: "cpu", "gpu"