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

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Message-ID: <CA+icZUU4d7mF2+MPvaZiSUCXF=0TdTYwWwW979zi_iQFz3gkVw@mail.gmail.com>
Date:	Thu, 31 Mar 2016 08:38:04 +0200
From:	Sedat Dilek <sedat.dilek@...il.com>
To:	"Rafael J. Wysocki" <rafael@...nel.org>
Cc:	"Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>,
	"Wysocki, Rafael J" <rafael.j.wysocki@...el.com>,
	"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>
Subject: Re: [intel-pstate driver regression] processor frequency very high
 even if in idle

On Thu, Mar 31, 2016 at 1:41 AM, Rafael J. Wysocki <rafael@...nel.org> wrote:
> On Thu, Mar 31, 2016 at 1:32 AM, Sedat Dilek <sedat.dilek@...il.com> wrote:
>> On Thu, Mar 31, 2016 at 1:28 AM, Rafael J. Wysocki <rafael@...nel.org> wrote:
>>> On Thu, Mar 31, 2016 at 1:25 AM, Sedat Dilek <sedat.dilek@...il.com> wrote:
>>>> On Thu, Mar 31, 2016 at 1:17 AM, Pandruvada, Srinivas
>>>> <srinivas.pandruvada@...el.com> wrote:
>>>>> 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?
>>>>>> >
>>>
>>> [cut]
>>>
>>>>
>>>> Too much questions.
>>>
>>> OK
>>>
>>>> I switched to CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE=y and tested with
>>>> the simplified revert-patch of Rafael.
>>>
>>> Why do you need the revert patch in the first place?
>>
>> I simply wanted to test CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE=y and
>> keep the rest.
>
> But it is not clear to us whether or not your system has regressed
> with respect to 4.5, which is the whole point of this thread.  Do you
> see a regression here?
>
> Jörg in particular is saying that he sees the problem with both
> performance and powersave settings.  What about you?

I have only tested with 4.6-rc1.
My 4.5 kernel has no CONFIG_X86_MSR=m which is mandatory for turbostat.

With CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE=y and without your
simplified revert-patch.
The values of Bzy_MHz look good for me.

CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y is somehow showing higher
values than TSC_MHz.
Not sure if this really make sense if TSC_MHz is a max-value (which I
don't know it is).

- Sedat -

View attachment "turbostat-i-1-msr-0x199-debug_4.6.0-rc1-14-iniza-small.txt" of type "text/plain" (62538 bytes)