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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 6A6CEC433DF for ; Mon, 3 Aug 2020 17:08:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4626E207DF for ; Mon, 3 Aug 2020 17:08:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727849AbgHCRIm (ORCPT ); Mon, 3 Aug 2020 13:08:42 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:42578 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726864AbgHCRIl (ORCPT ); Mon, 3 Aug 2020 13:08:41 -0400 Received: from 89-64-89-42.dynamic.chello.pl (89.64.89.42) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.415) id 85810bff8759e0f8; Mon, 3 Aug 2020 19:08:39 +0200 From: "Rafael J. Wysocki" To: Doug Smythies Cc: "'Rafael J. Wysocki'" , 'Linux Documentation' , 'LKML' , 'Peter Zijlstra' , 'Srinivas Pandruvada' , 'Giovanni Gherdovich' , 'Francisco Jerez' , 'Linux PM' Subject: Re: [PATCH] cpufreq: intel_pstate: Implement passive mode with HWP enabled Date: Mon, 03 Aug 2020 19:08:38 +0200 Message-ID: <2418846.A4mPlhI7ni@kreacher> In-Reply-To: <000b01d668e0$11508160$33f18420$@net> References: <3955470.QvD6XneCf3@kreacher> <000b01d668e0$11508160$33f18420$@net> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Sunday, August 2, 2020 5:17:39 PM CEST Doug Smythies wrote: > Hi Rafael, > > On 2020.07.19 04:43 Rafael J. Wysocki wrote: > > On Fri, Jul 17, 2020 at 3:37 PM Doug Smythies wrote: > > > On 2020.07.16 05:08 Rafael J. Wysocki wrote: > > > > On Wed, Jul 15, 2020 at 10:39 PM Doug Smythies wrote: > > > >> On 2020.07.14 11:16 Rafael J. Wysocki wrote: > > > >> > > > > >> > From: Rafael J. Wysocki > > > >> ... > > > >> > Since the passive mode hasn't worked with HWP at all, and it is not going to > > > >> > the default for HWP systems anyway, I don't see any drawbacks related to making > > > >> > this change, so I would consider this as 5.9 material unless there are any > > > >> > serious objections. > > > >> > > > >> Good point. > > > > > > Actually, for those users that default to passive mode upon boot, > > > this would mean they would find themselves using this. > > > Also, it isn't obvious, from the typical "what driver and what governor" > > > inquiry. > > > > So the change in behavior is that after this patch > > intel_pstate=passive doesn't imply no_hwp any more. > > > > That's a very minor difference though and I'm not aware of any adverse > > effects it can cause on HWP systems anyway. > > My point was, that it will now default to something where > testing has not been completed. > > > The "what governor" is straightforward in the passive mode: that's > > whatever cpufreq governor has been selected. > > I think you might have missed my point. > From the normal methods of inquiry one does not know > if HWP is being used or not. Why? Because with > or without HWP one gets the same answers under: > > /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver > /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor Yes, but this is also the case in the active mode, isn't it? Thanks!