linux-kernel - Re: [intel-pstate driver regression] processor frequency very high even if in idle

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Date:	Wed, 30 Mar 2016 23:17:10 +0000
From:	"Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>
To:	"Wysocki, Rafael J" <rafael.j.wysocki@...el.com>
CC:	"dsmythies@...us.net" <dsmythies@...us.net>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"jrg.otte@...il.com" <jrg.otte@...il.com>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"sedat.dilek@...il.com" <sedat.dilek@...il.com>,
	"rafael@...nel.org" <rafael@...nel.org>
Subject: Re: [intel-pstate driver regression] processor frequency very high
 even if in idle

On Wed, 2016-03-30 at 15:46 -0700, Srinivas Pandruvada wrote:
> On Thu, 2016-03-31 at 00:25 +0200, Rafael J. Wysocki wrote:
> > 
> > On 3/31/2016 12:18 AM, Srinivas Pandruvada wrote:
> > > 
> > > 
> > > On Wed, 2016-03-30 at 23:41 +0200, Sedat Dilek wrote:
> > > > 
> > > > 
> > > > Hi,
> > > > 
> > > > I am using Intel-PState-Driver here with v4.6-rc1 and Intel-
> > > > SandyBridge-CPU.
> > > > 
> > > > Here are my turbostat results attached.
> > > > 
> > > > $ cd $BUILD_DIR
> > > > $ LC_ALL=C make -C tools/ turbostat
> > > > 
> > > > $ sudo ./turbostat -i 1 --msr=0x199 --debug --out
> > > > /tmp/turbostat-i-1-msr-0x199-debug.txt
> > > > 
> > > > Will try <https://patchwork.kernel.org/patch/8702071/>.
> > > > 
> > > > Please see attached files.
> > > > 
> > > Thanks. Your logs make sense. You have config set to performance
> > > mode
> > > by default (Which I believe default in all kernel Ubuntu). So as
> > > expected Intel P state was asking for max. So there is no issue
> > > here.
> > But the behavior is different from what it used to be, isn't it?
> > 
> There are two turbostat output files, In both I see we are requesting
> max (0x1700) in performance mode. This CPU is Sandybridge, so no
> config
> TDP here, the other problem system reported is Haswell
> .
>  0       1       3    0.15    2017    1596  0x00001700 
> 
> I am not sure whether Sedat is saying that he has the same issue as
> Jorg. I think Sedat will see the same turbostat output if he ran 4.5.
> 
I takeback my statements. It will depend on when he ran turbostat, is
it within a minute or so. As doug suggested, ubuntu changes the mode to
powersave, then we shouldn't see 0x1700 in MSR 0x199.
Sedat,
What is the output of 
cat /sys/devices/system/cpu/cpu?/cpufreq/scaling_governor 

Thanks,
Srinivas

> Sedat, 
> Please confirm whether you see difference between 4.5 and 4.6-rc1.
> 
> Thanks,
> Srinivas
> 
> > 
> > So there seems to be a problem here AFAICS.
> > 
> > --
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