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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 93FAFECDFB3 for ; Tue, 17 Jul 2018 09:27:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5014F20C0B for ; Tue, 17 Jul 2018 09:27:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5014F20C0B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.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 S1730238AbeGQJ7I (ORCPT ); Tue, 17 Jul 2018 05:59:08 -0400 Received: from smtp.nue.novell.com ([195.135.221.5]:39436 "EHLO smtp.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729036AbeGQJ7I (ORCPT ); Tue, 17 Jul 2018 05:59:08 -0400 Received: from emea4-mta.ukb.novell.com ([10.120.13.87]) by smtp.nue.novell.com with ESMTP (TLS encrypted); Tue, 17 Jul 2018 11:27:26 +0200 Received: from suselix (nwb-a10-snat.microfocus.com [10.120.13.201]) by emea4-mta.ukb.novell.com with ESMTP (TLS encrypted); Tue, 17 Jul 2018 10:27:23 +0100 Date: Tue, 17 Jul 2018 11:27:21 +0200 From: Andreas Herrmann To: "Rafael J. Wysocki" Cc: "Rafael J. Wysocki" , Peter Zijlstra , Frederic Weisbecker , Viresh Kumar , Linux PM , Linux Kernel Mailing List Subject: Re: Commit 554c8aa8ecad causing severe performance degression with pcc-cpufreq Message-ID: <20180717092721.onkaf3qsu7te6syi@suselix> References: <20180717065048.74mmgk4t5utjaa6a@suselix> <20180717085039.kqxwbkgruhj5qxtx@suselix> <20180717091152.l4ixicbp6imvqtsr@suselix> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 17, 2018 at 11:23:25AM +0200, Rafael J. Wysocki wrote: > On Tue, Jul 17, 2018 at 11:11 AM, Andreas Herrmann wrote: > > On Tue, Jul 17, 2018 at 11:06:29AM +0200, Rafael J. Wysocki wrote: > >> On Tue, Jul 17, 2018 at 10:50 AM, Andreas Herrmann wrote: > >> > >> [cut] > >> > >> > > >> > On balance before this commit users could use pcc-cpufreq but had > >> > already suboptimal performance (compared to say intel_pstate driver > >> > which can be used changing BIOS options). > >> > >> BTW, I wonder why you need to change the BIOS options for intel_pstate to load. > > > > I think this is because of (in intel_pstate_init()): > > > > /* > > * The Intel pstate driver will be ignored if the platform > > * firmware has its own power management modes. > > */ > > if (intel_pstate_platform_pwr_mgmt_exists()) > > return -ENODEV; > > > > OK, because of the "Proliant" entry, right? > > So it looks like we have an issue there. We find the entry and we > look for _PSS. It is not there, so we assume that the firmware is > expected to control performance, which is not the case. It looks like > we also should look for the presence of the PCC interface in there. > > I can provide a patch for that, will you be able to test it? Yes, I can test it. > >> It should be initialized before pcc-cpufreq (according to their > >> respective initcall levels), so in theory intel_pstate should be used > >> by default on the affected systems anyway. > > > >> What BIOS settings need to be changed for that? > > > > Already answered in other mail. > > Indeed. Andreas