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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 3530EC2BA2B for ; Tue, 7 Apr 2020 15:35:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 093C02076E for ; Tue, 7 Apr 2020 15:35:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729100AbgDGPfa (ORCPT ); Tue, 7 Apr 2020 11:35:30 -0400 Received: from mx2.suse.de ([195.135.220.15]:55530 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729127AbgDGPfa (ORCPT ); Tue, 7 Apr 2020 11:35:30 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id D84BAAC77; Tue, 7 Apr 2020 15:35:27 +0000 (UTC) Message-ID: <1586273727.1721.20.camel@suse.cz> Subject: Re: [PATCH 0/2] cpufreq: intel_pstate: Run in the passive mode by default on systems without HWP From: Giovanni Gherdovich To: "Rafael J. Wysocki" , Linux PM , Srinivas Pandruvada Cc: LKML , "Rafael J. Wysocki" , Viresh Kumar , Doug Smythies Date: Tue, 07 Apr 2020 17:35:27 +0200 In-Reply-To: <2016232.ihCVsphvri@kreacher> References: <2016232.ihCVsphvri@kreacher> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Sat, 2020-03-28 at 13:54 +0100, Rafael J. Wysocki wrote: > Hi All, > > These two patches modify the intel_pstate driver to run in the passive mode by > default on systems without HWP (refer to the changelog of patch [2/2] for the > motivation part). > > Internal testing of the system performance in 5.6-rc indicates that the > difference between the active mode with the powersave scaling algorithm and the > passive mode with the schedutil governor should be negligible for the majority > of users, so it should be safe to change the default behavior of the driver as > per the above. > > Patch [1/2] makes changes to select the schedutil governor and set it as the > default one when intel_pstate is selected in Kconfig. > > Patch [2/2] changes intel_pstate to start in the passive by default if HWP is > not supported (or if it is disabled via the kernel command line). > > Please refer to the patch changelogs for more information. > Hello Rafael, just to say that I'm very happy about this patch; I see it as a sensible roll-out strategy for wide adoption of schedutil on x86, as it initially applies to non-HWP only and not to the entire processor model range. As we get more reports of its behavior on the field, we'll see when and how to move forward from there. I didn't reply last week as I was handling some bug reports for frequency invariance on x86; one from LKML (Chris Wilson from Intel found that it crashes when cpu0 is taken offline) and two more reported internally at SUSE. Nothing major though, I am writing fixes for all those and will send a bugfix series within the next few days. Thanks! Giovanni