Messages in this thread | | | From | "Pandruvada, Srinivas" <> | Subject | Re: [REGRESSION] 774ac8b7eff6 ("Thermal: initialize thermal zone device correctly") causes performance drop | Date | Thu, 17 Mar 2016 00:20:35 +0000 |
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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 <rui.zhang@intel.com> > > > 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 <manuelkrause@netscape.net> > > > Tested-by: szegad <szegadlo@poczta.onet.pl> > > > Tested-by: prash <prash.n.rao@gmail.com> > > > Tested-by: amish <ammdispose-arch@yahoo.com> > > > Tested-by: Matthias <morpheusxyz123@yahoo.de> > > > Reviewed-by: Javi Merino <javi.merino@arm.com> > > > Signed-off-by: Zhang Rui <rui.zhang@intel.com> > > > Signed-off-by: Chen Yu <yu.c.chen@intel.com> > > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.or > > > 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 | |