From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755600AbcCQAUi (ORCPT ); Wed, 16 Mar 2016 20:20:38 -0400 Received: from mga02.intel.com ([134.134.136.20]:4962 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751118AbcCQAUh (ORCPT ); Wed, 16 Mar 2016 20:20:37 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,346,1455004800"; d="scan'208";a="765711888" From: "Pandruvada, Srinivas" To: "labbott@redhat.com" , "gregkh@linuxfoundation.org" CC: "ammdispose-arch@yahoo.com" , "linux-kernel@vger.kernel.org" , "Zhang, Rui" , "Chen, Yu C" , "manuelkrause@netscape.net" , "linux-pm@vger.kernel.org" , "szegadlo@poczta.onet.pl" , "prash.n.rao@gmail.com" , "javi.merino@arm.com" , "morpheusxyz123@yahoo.de" Subject: Re: [REGRESSION] 774ac8b7eff6 ("Thermal: initialize thermal zone device correctly") causes performance drop Thread-Topic: [REGRESSION] 774ac8b7eff6 ("Thermal: initialize thermal zone device correctly") causes performance drop Thread-Index: AQHRf+LSfAyVGhXqhkWfvACrwJfakg== Date: Thu, 17 Mar 2016 00:20:35 +0000 Message-ID: <1458173863.4703.18.camel@intel.com> References: <56E9DDED.7000805@redhat.com> <20160316224634.GA3580@kroah.com> <56E9F387.9080703@redhat.com> In-Reply-To: <56E9F387.9080703@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.254.16.35] Content-Type: text/plain; charset="utf-8" Content-ID: <2B33502BE4F6D944AB3D36EB24E51EB3@intel.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id u2H0KhZo016043 On Wed, 2016-03-16 at 17:00 -0700, Laura Abbott wrote: > On 03/16/2016 03:46 PM, Greg Kroah-Hartman wrote: > > On Wed, Mar 16, 2016 at 03:27:57PM -0700, Laura Abbott wrote: > > > Hi, > > > > > > Fedora received a bug report (https://bugzilla.redhat.com/show_bu > > > g.cgi?id=1317190) > > > of a major performance drop on various bench marks and general > > > system > > > sluggishness with the 4.4.4 kernel update. The benchmarks were > > > showing > > > a reduction to about 18% performance (not minor). > > > > > > Bisection showed the first bad commit was > > > > > > commit 774ac8b7eff69e0786970157de2157e68b22f456 > > > Author: Zhang Rui > > > Date:   Fri Oct 30 16:31:47 2015 +0800 > > > > > >      Thermal: initialize thermal zone device correctly > > >      commit bb431ba26c5cd0a17c941ca6c3a195a3a6d5d461 upstream. > > >      After thermal zone device registered, as we have not read > > > any > > >      temperature before, thus tz->temperature should not be 0, > > >      which actually means 0C, and thermal trend is not available. > > >      In this case, we need specially handling for the first > > >      thermal_zone_device_update(). > > >      Both thermal core framework and step_wise governor is > > >      enhanced to handle this. And since the step_wise governor > > >      is the only one that uses trends, so it's the only thermal > > >      governor that needs to be updated. > > >      Tested-by: Manuel Krause > > >      Tested-by: szegad > > >      Tested-by: prash > > >      Tested-by: amish > > >      Tested-by: Matthias > > >      Reviewed-by: Javi Merino > > >      Signed-off-by: Zhang Rui > > >      Signed-off-by: Chen Yu > > >      Signed-off-by: Greg Kroah-Hartman > > g> > > > > > > > > > > > > Reverting this plus to other commits in the series (a67208e94d94 > > > "Thermal: handle thermal zone device properly during system > > > sleep" > > > and 27f356149d59 "Thermal: do thermal zone update after a cooling > > > device registered") confirmed the performance was back to normal. > > > > > > Bugzilla has the full discussion but this comment from one of the > > > reporters sums it up: > > > > > > "In 4.4.3 and prior, my 2.40 MHz processor would fluctuate > > > between > > > 1000 and 3400 MHz.  In 4.4.4, the processor would fluctuate > > > between > > > 400 and 700 MHz, according to /proc/cpuinfo. > > > > > > Setting /sys/devices/system/cpu/cpufreq/policy0/scaling_governor > > > to > > > performance, instead of the default "powersave" forces the CPU to > > > 2400 MHz, and improves performance greatly, but still not to the > > > same level as in 4.4.3." > > > > > > Any ideas? > > > > Is this same "slowdown" also seen in 4.5? > > > > thanks, > > > > greg k-h > > > > Yes, the same issue is seen on 4.5 according to the reporter. What does it show here when performance drops? grep . /sys/devices/system/cpu/intel_pstate/* Is the problem still occurs if you set  /sys/class/thermal/thermal_zone*/mode to "disabled"  Thanks, Srinivas > > Thanks, > Laura > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" > in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html