From patchwork Wed May 12 14:14:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 435999 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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS 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 22E53C43470 for ; Wed, 12 May 2021 14:21:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E21A8613F7 for ; Wed, 12 May 2021 14:21:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230505AbhELOXD (ORCPT ); Wed, 12 May 2021 10:23:03 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:46402 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230471AbhELOXB (ORCPT ); Wed, 12 May 2021 10:23:01 -0400 Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 2.0.5) id 602755e1f585e2c0; Wed, 12 May 2021 16:21:51 +0200 Received: from kreacher.localnet (89-64-81-242.dynamic.chello.pl [89.64.81.242]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by v370.home.net.pl (Postfix) with ESMTPSA id DE39E6695E9; Wed, 12 May 2021 16:21:50 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM Cc: Linux ACPI , LKML , Len Brown , Chen Yu , Srinivas Pandruvada , Zhang Rui Subject: [PATCH 0/2] cpufreq: intel_pstate: HWP support on hybrid processors Date: Wed, 12 May 2021 16:14:18 +0200 Message-ID: <2212930.ElGaqSPkdT@kreacher> MIME-Version: 1.0 X-CLIENT-IP: 89.64.81.242 X-CLIENT-HOSTNAME: 89-64-81-242.dynamic.chello.pl X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduledrvdehvddgjedvucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecujffqoffgrffnpdggtffipffknecuuegrihhlohhuthemucduhedtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvffufffkggfgtgesthfuredttddtjeenucfhrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqeenucggtffrrghtthgvrhhnpefhgedtffejheekgeeljeevvedtuefgffeiieejuddutdekgfejvdehueejjeetvdenucfkphepkeelrdeigedrkedurddvgedvnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepkeelrdeigedrkedurddvgedvpdhhvghlohepkhhrvggrtghhvghrrdhlohgtrghlnhgvthdpmhgrihhlfhhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqpdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqrggtphhisehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhgvnhdrsghrohifnhesihhnthgvlhdrtghomhdprhgtphhtthhopeihuhdrtgdrtghhvghnsehinhhtvghlrdgtohhm pdhrtghpthhtohepshhrihhnihhvrghsrdhprghnughruhhvrggurgeslhhinhhugidrihhnthgvlhdrtghomhdprhgtphhtthhopehruhhirdiihhgrnhhgsehinhhtvghlrdgtohhm X-DCC--Metrics: v370.home.net.pl 1024; Body=7 Fuz1=7 Fuz2=7 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi All, In Intel Hybrid processors there are cores with different micro-architecture, so the relationship between CPU frequency and performance is generally not uniform across all CPUs. Because the units of CPU performance used in the MSR_HWP_CAPABILITIES and MSR_HWP_REQUEST registers are the same for all CPUs, the scaling between HWP performance levels and frequency generally depends on the core type and it is not uniform across all CPUs either, so some assumptions made by intel_pstate are not applicable to hybrid processors. As the scaling factor between HWP performance and frequency will now generally depend on the CPU, in particular it cannot be assumed to be equal to the scaling factor between P-states and frequency for all CPUs which has been one of the assumptions made so far by intel_pstate. Unfortunately, in general it is not very straightforward to determine that scaling factor which is the purpose of patch [2/2] (please refer to the changelog of that patch for details). Moreover, two of the global sysfs attributes exposed by intel_pstate only work as expected if all CPUs have the same number of HWP performance levels, so it is better to avoid exposing those attributes when running on hybrid processors, which is taken care of by patch [1/2]. Thanks!