From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Doug Smythies" Subject: RE: [PATCH 0/5] intel_pstate: Use C0 time, calculate target pstate directly Date: Mon, 13 Apr 2015 14:16:10 -0700 Message-ID: <001a01d0762f$117316c0$34594440$@net> References: <1428811830-15006-1-git-send-email-dsmythies@telus.net> <20150413093214.63dc6184@kcaccard-desk.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from cmta5.telus.net ([209.171.16.78]:53392 "EHLO cmta5.telus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751020AbbDMVQP (ORCPT ); Mon, 13 Apr 2015 17:16:15 -0400 In-Reply-To: <20150413093214.63dc6184@kcaccard-desk.amr.corp.intel.com> Content-Language: en-ca Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: 'Kristen Carlson Accardi' Cc: rjw@rjwysocki.net, linux-pm@vger.kernel.org Hi Kristen, Thanks for your quick and positive reply. On 2015.04.13 09:32 Kristen wrote: > On Sat, 11 Apr 2015 21:10:25 -0700 Doug Smythies wrote: > Thanks for your patches, I'll be doing some testing and review and let > you know how things go. And from the other thread: > I'm going to need to do a lot of > benchmarking on a variety of platforms to make sure we haven't regressed > anything. Yes, of course. I make no claim to have found the best default operating parameters, IIR gain, c0_floor, c0_ceiling, sample_rate_ms. I only have a i7-2600K to test with. Other results: Phoronix: Kernel compile: acpi-cpufreq: 122.4 seconds 4.0RC7, unpatched: 121.8 seconds Patched: 122.4 seconds Phoronix: Apache: acpi-cpufreq: 19429 4.0RC7, unpatched: 20089 Patched: 20410 Phoronix: ffmpeg: acpi-cpufreq: 17.06 seconds and 1444.36 Joules Package Energy. 4.0RC7, unpatched: 17.65 seconds and 1444.36 Joules Patched: 23.1 seconds and 1302 Joules Note: Dirk proved that the ffmpeg test does odd switching of CPUs when they become 50% loaded. With the settings I have used for c0_floor and c0_ceiling, these results are not a surprise. 2000 Seconds idle (server): Unpatched: 7704 Joules Patched: 7625 Joules. An i5-4690K running some Ubuntu desktop, but otherwise idle: Average CPU frequency goes way down and power consumption drops by just over half a watt. An i7-4790K running xorg and Arch distro, but otherwise idle: Average CPU frequency drops considerably, and power consumption is about the same. Note: unpatched CPU frequencies were not as high as previously reported on that bugzilla report. I do not know why. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=93521 Still waiting to hear from the other i7-4790K user that had high CPU frequency when idle issues. There is a bit of evidence that the unpatched reference kernel might do a little better at holding CPU frequencies lower in the low load 20 Hz work / sleep frequency range. I'm still looking at that scenario. There are many graphs at: Double u double u double u dot smythies dot com /~doug/linux/intel_pstate/build220/index.html ... Doug