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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 2A459C6778F for ; Sat, 28 Jul 2018 14:14:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2AFE20873 for ; Sat, 28 Jul 2018 14:14:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E2AFE20873 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.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 S1728965AbeG1PlG (ORCPT ); Sat, 28 Jul 2018 11:41:06 -0400 Received: from mga07.intel.com ([134.134.136.100]:15529 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728896AbeG1PlG (ORCPT ); Sat, 28 Jul 2018 11:41:06 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Jul 2018 07:14:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,414,1526367600"; d="scan'208";a="244102098" Received: from spandruv-mobl.amr.corp.intel.com ([10.254.6.133]) by orsmga005.jf.intel.com with ESMTP; 28 Jul 2018 07:14:25 -0700 Message-ID: <3afad4b13370fe0ba6ed5020f86ce1b8ff46c603.camel@linux.intel.com> Subject: Re: [PATCH 4/4] cpufreq: intel_pstate: enable boost for Skylake Xeon From: Srinivas Pandruvada To: Francisco Jerez , lenb@kernel.org, rjw@rjwysocki.net, mgorman@techsingularity.net Cc: peterz@infradead.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, juri.lelli@redhat.com, viresh.kumar@linaro.org, ggherdovich@suse.cz, Chris Wilson , Tvrtko Ursulin , Joonas Lahtinen , Eero Tamminen Date: Sat, 28 Jul 2018 07:14:24 -0700 In-Reply-To: <87bmarhqk4.fsf@riseup.net> References: <20180605214242.62156-1-srinivas.pandruvada@linux.intel.com> <20180605214242.62156-5-srinivas.pandruvada@linux.intel.com> <87bmarhqk4.fsf@riseup.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.3 (3.28.3-1.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2018-07-27 at 22:34 -0700, Francisco Jerez wrote: > Srinivas Pandruvada writes: > > > Enable HWP boost on Skylake server and workstations. > > > > Please revert this series, it led to significant energy usage and > graphics performance regressions [1]. Which SKX platform is targeted to graphics? > The reasons are roughly the ones > we discussed by e-mail off-list last April: This causes the > intel_pstate > driver to decrease the EPP to zero No. You didn't check this series. We are not using EPP at all. The boost mechanism used here is not boost to max. Thanks, Srinivas > when the workload blocks on IO > frequently enough, which for the regressing benchmarks detailed in > [1] > is a symptom of the workload being heavily IO-bound, which means they > won't benefit at all from the EPP boost since they aren't > significantly > CPU-bound, and they will suffer a decrease in parallelism due to the > active CPU core using a larger fraction of the TDP in order to > achieve > the same work, causing the GPU to have a lower power budget > available, > leading to a decrease in system performance. > > You may want to give a shot to my previous suggestion of using [2] in > order to detect whether the system is IO-bound, which you can use as > an > indicator that the optimization implemented in this series cannot > possibly improve performance and can be expected to hurt energy > usage. > > Thanks. > > [1] https://bugs.freedesktop.org/show_bug.cgi?id=107410 > [2] https://patchwork.kernel.org/patch/10312259/ > > > Reported-by: Mel Gorman > > Tested-by: Giovanni Gherdovich > > Signed-off-by: Srinivas Pandruvada > .com> > > --- > > drivers/cpufreq/intel_pstate.c | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/drivers/cpufreq/intel_pstate.c > > b/drivers/cpufreq/intel_pstate.c > > index 70bf63bb4e0e..01c8da1f99db 100644 > > --- a/drivers/cpufreq/intel_pstate.c > > +++ b/drivers/cpufreq/intel_pstate.c > > @@ -1794,6 +1794,12 @@ static const struct x86_cpu_id > > intel_pstate_cpu_ee_disable_ids[] = { > > {} > > }; > > > > +static const struct x86_cpu_id intel_pstate_hwp_boost_ids[] > > __initconst = { > > + ICPU(INTEL_FAM6_SKYLAKE_X, core_funcs), > > + ICPU(INTEL_FAM6_SKYLAKE_DESKTOP, core_funcs), > > + {} > > +}; > > + > > static int intel_pstate_init_cpu(unsigned int cpunum) > > { > > struct cpudata *cpu; > > @@ -1824,6 +1830,10 @@ static int intel_pstate_init_cpu(unsigned > > int cpunum) > > intel_pstate_disable_ee(cpunum); > > > > intel_pstate_hwp_enable(cpu); > > + > > + id = x86_match_cpu(intel_pstate_hwp_boost_ids); > > + if (id) > > + hwp_boost = true; > > } > > > > intel_pstate_get_cpu_pstates(cpu); > > -- > > 2.13.6