cpufreq turbo regression

cpufreq turbo regression

[Ross Lagerwall]

Hi,

I have an Intel 3570K and would like to run it in performance mode from
startup so I set the default governor to performance.

I noticed that when I do this, turbo mode does not seem to be activated
on the processor (turbostat shows frequencies of about 3.4GHz rather
than 3.7GHz).  If I then while it is running switch to ondemand and then back
to performance, turbo is activated properly and the cpu frequency hits 3.7GHz.

I did a git bisect and traced it to the following commit:
5a1c022850ea5d64c2997bf9b89f5ae112d5ee4d is the first bad commit
commit 5a1c022850ea5d64c2997bf9b89f5ae112d5ee4d
Author: Viresh Kumar <viresh.kumar@linaro.org>
Date:   Wed Oct 31 01:28:15 2012 +0100

    cpufreq: Avoid calling cpufreq driver's target() routine if target_freq == policy->cur
    
    Avoid calling cpufreq driver's target() routine if new frequency is same as
    policies current frequency.
    
    Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

:040000 040000 4e0d340c501120d61e5bb9553420c142037a0beb f4ed149e8563bebd6e2d1e4c56523ff9aed4314b M  drivers

Reverting this commit from v3.10-rc3 fixed the problem.

This is using the acpi-cpufreq driver -- there doesn't seem to be any way to
set the Intel P-state driver to performance by default.

Regards
-- 
Ross Lagerwall

Re: cpufreq turbo regression

[Viresh Kumar]

On 30 May 2013 19:22, Ross Lagerwall <rosslagerwall@gmail.com> wrote:
> I have an Intel 3570K and would like to run it in performance mode from
> startup so I set the default governor to performance.
>
> I noticed that when I do this, turbo mode does not seem to be activated
> on the processor (turbostat shows frequencies of about 3.4GHz rather
> than 3.7GHz).  If I then while it is running switch to ondemand and then back
> to performance, turbo is activated properly and the cpu frequency hits 3.7GHz.
>
> I did a git bisect and traced it to the following commit:
> 5a1c022850ea5d64c2997bf9b89f5ae112d5ee4d is the first bad commit
> commit 5a1c022850ea5d64c2997bf9b89f5ae112d5ee4d
> Author: Viresh Kumar <viresh.kumar@linaro.org>
> Date:   Wed Oct 31 01:28:15 2012 +0100
>
>     cpufreq: Avoid calling cpufreq driver's target() routine if target_freq == policy->cur
>
>     Avoid calling cpufreq driver's target() routine if new frequency is same as
>     policies current frequency.
>
>     Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>     Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> :040000 040000 4e0d340c501120d61e5bb9553420c142037a0beb f4ed149e8563bebd6e2d1e4c56523ff9aed4314b M  drivers
>
> Reverting this commit from v3.10-rc3 fixed the problem.
>
> This is using the acpi-cpufreq driver -- there doesn't seem to be any way to
> set the Intel P-state driver to performance by default.

This patch was pretty much sensible and all drivers now depend on it
now.

@Dirk: Can you please help us in understanding why this might be
happening. I believe it has to do with some bad design of acpi-cpufreq
driver (I tried to look into target routine but couldn't understand why
this might be happening).

--
viresh

Re: cpufreq turbo regression

[Dirk Brandewie]

On 05/30/2013 08:41 AM, Viresh Kumar wrote:
>> Reverting this commit from v3.10-rc3 fixed the problem.
>>
>> This is using the acpi-cpufreq driver -- there doesn't seem to be any way to
>> set the Intel P-state driver to performance by default.
>
> This patch was pretty much sensible and all drivers now depend on it
> now.
>
> @Dirk: Can you please help us in understanding why this might be
> happening. I believe it has to do with some bad design of acpi-cpufreq
> driver (I tried to look into target routine but couldn't understand why
> this might be happening).
>

Not really sorry I don't know any thing about acpi-cpufreq.

> --
> viresh
> --
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>

Re: cpufreq turbo regression

[Ross Lagerwall]

On Thu, May 30, 2013 at 09:11:12PM +0530, Viresh Kumar wrote:
> This patch was pretty much sensible and all drivers now depend on it
> now.
> 
> @Dirk: Can you please help us in understanding why this might be
> happening. I believe it has to do with some bad design of acpi-cpufreq
> driver (I tried to look into target routine but couldn't understand why
> this might be happening).
> 

Here is some more relevant info:
It seems like turbo is correctly set up on core 0.
If I run "taskset -c 0 stress -c 1", the frequency of core 0 jumps to
~3.8GHz.  Repeating with core 1, 2 or 3 leaves the frequency of the
respective core at 3.4GHz (no turbo).

I turned on logging and got:
[    0.570749] acpi_cpufreq_init
[    0.570750] acpi_cpufreq_early_init
[    0.570828] cpufreq: trying to register driver acpi-cpufreq
[    0.570829] cpufreq: adding CPU 0
[    0.570830] acpi_cpufreq_cpu_init
[    0.570869] HARDWARE addr space
[    0.570870] get_cur_freq_on_cpu (0)
[    0.570872] get_cur_val = 8704
[    0.570872] cur freq = 3400000
[    0.570873] CPU0 - ACPI performance management activated.
[    0.570874]      *P0: 3401 MHz, 77000 mW, 10 uS
[    0.570875]       P1: 3400 MHz, 77000 mW, 10 uS
[    0.570876]       P2: 3300 MHz, 73840 mW, 10 uS
[    0.570877]       P3: 3100 MHz, 67694 mW, 10 uS
[    0.570878]       P4: 3000 MHz, 64705 mW, 10 uS
[    0.570879]       P5: 2900 MHz, 61772 mW, 10 uS
[    0.570879]       P6: 2800 MHz, 58907 mW, 10 uS
[    0.570880]       P7: 2600 MHz, 53315 mW, 10 uS
[    0.570881]       P8: 2500 MHz, 50601 mW, 10 uS
[    0.570882]       P9: 2400 MHz, 47940 mW, 10 uS
[    0.570883]       P10: 2200 MHz, 42787 mW, 10 uS
[    0.570884]       P11: 2100 MHz, 40284 mW, 10 uS
[    0.570885]       P12: 2000 MHz, 37833 mW, 10 uS
[    0.570885]       P13: 1900 MHz, 35433 mW, 10 uS
[    0.570886]       P14: 1700 MHz, 31421 mW, 10 uS
[    0.570887]       P15: 1600 MHz, 29164 mW, 10 uS
[    0.570896] cpufreq: setting new policy for CPU 0: 1600000 - 3401000 kHz
[    0.570897] acpi_cpufreq_verify
[    0.570898] acpi_cpufreq_verify
[    0.570899] cpufreq: new min and max freqs are 1600000 - 3401000 kHz
[    0.570899] cpufreq: governor switch
[    0.570900] cpufreq: __cpufreq_governor for CPU 0, event 4
[    0.570901] cpufreq: __cpufreq_governor for CPU 0, event 1
[    0.570902] target for CPU 0: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.570903] acpi_cpufreq_target 3401000 (0)
[    0.570904] Called after resume, resetting to P0
[    0.570905] cpufreq: notification 0 of frequency transition to 3401000 kHz
[    0.570907] cpufreq: notification 1 of frequency transition to 3401000 kHz
[    0.570908] cpufreq: FREQ: 3401000 - CPU: 0
[    0.570909] cpufreq: governor: change or update limits
[    0.570909] cpufreq: __cpufreq_governor for CPU 0, event 3
[    0.570910] target for CPU 0: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.570911] cpufreq: initialization complete
[    0.570912] cpufreq: adding CPU 1
[    0.570913] acpi_cpufreq_cpu_init
[    0.570986] HARDWARE addr space
[    0.570999] get_cur_freq_on_cpu (1)
[    0.571001] get_cur_val = 9728
[    0.571001] cur freq = 3401000
[    0.571002] CPU1 - ACPI performance management activated.
[    0.571003]      *P0: 3401 MHz, 77000 mW, 10 uS
[    0.571003]       P1: 3400 MHz, 77000 mW, 10 uS
[    0.571004]       P2: 3300 MHz, 73840 mW, 10 uS
[    0.571005]       P3: 3100 MHz, 67694 mW, 10 uS
[    0.571006]       P4: 3000 MHz, 64705 mW, 10 uS
[    0.571006]       P5: 2900 MHz, 61772 mW, 10 uS
[    0.571007]       P6: 2800 MHz, 58907 mW, 10 uS
[    0.571008]       P7: 2600 MHz, 53315 mW, 10 uS
[    0.571009]       P8: 2500 MHz, 50601 mW, 10 uS
[    0.571009]       P9: 2400 MHz, 47940 mW, 10 uS
[    0.571010]       P10: 2200 MHz, 42787 mW, 10 uS
[    0.571011]       P11: 2100 MHz, 40284 mW, 10 uS
[    0.571012]       P12: 2000 MHz, 37833 mW, 10 uS
[    0.571013]       P13: 1900 MHz, 35433 mW, 10 uS
[    0.571013]       P14: 1700 MHz, 31421 mW, 10 uS
[    0.571014]       P15: 1600 MHz, 29164 mW, 10 uS
[    0.571019] cpufreq: setting new policy for CPU 1: 1600000 - 3401000 kHz
[    0.571020] acpi_cpufreq_verify
[    0.571020] acpi_cpufreq_verify
[    0.571021] cpufreq: new min and max freqs are 1600000 - 3401000 kHz
[    0.571022] cpufreq: governor switch
[    0.571022] cpufreq: __cpufreq_governor for CPU 1, event 4
[    0.571023] cpufreq: __cpufreq_governor for CPU 1, event 1
[    0.571024] target for CPU 1: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.571024] cpufreq: governor: change or update limits
[    0.571025] cpufreq: __cpufreq_governor for CPU 1, event 3
[    0.571025] target for CPU 1: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.571026] cpufreq: initialization complete
[    0.571027] cpufreq: adding CPU 2
[    0.571027] acpi_cpufreq_cpu_init
[    0.571069] HARDWARE addr space
[    0.571070] get_cur_freq_on_cpu (2)
[    0.571107] get_cur_val = 9728
[    0.571108] cur freq = 3401000
[    0.571108] CPU2 - ACPI performance management activated.
[    0.571109]      *P0: 3401 MHz, 77000 mW, 10 uS
[    0.571110]       P1: 3400 MHz, 77000 mW, 10 uS
[    0.571111]       P2: 3300 MHz, 73840 mW, 10 uS
[    0.571111]       P3: 3100 MHz, 67694 mW, 10 uS
[    0.571112]       P4: 3000 MHz, 64705 mW, 10 uS
[    0.571113]       P5: 2900 MHz, 61772 mW, 10 uS
[    0.571114]       P6: 2800 MHz, 58907 mW, 10 uS
[    0.571114]       P7: 2600 MHz, 53315 mW, 10 uS
[    0.571115]       P8: 2500 MHz, 50601 mW, 10 uS
[    0.571116]       P9: 2400 MHz, 47940 mW, 10 uS
[    0.571117]       P10: 2200 MHz, 42787 mW, 10 uS
[    0.571117]       P11: 2100 MHz, 40284 mW, 10 uS
[    0.571118]       P12: 2000 MHz, 37833 mW, 10 uS
[    0.571119]       P13: 1900 MHz, 35433 mW, 10 uS
[    0.571120]       P14: 1700 MHz, 31421 mW, 10 uS
[    0.571121]       P15: 1600 MHz, 29164 mW, 10 uS
[    0.571126] cpufreq: setting new policy for CPU 2: 1600000 - 3401000 kHz
[    0.571127] acpi_cpufreq_verify
[    0.571128] acpi_cpufreq_verify
[    0.571128] cpufreq: new min and max freqs are 1600000 - 3401000 kHz
[    0.571129] cpufreq: governor switch
[    0.571129] cpufreq: __cpufreq_governor for CPU 2, event 4
[    0.571130] cpufreq: __cpufreq_governor for CPU 2, event 1
[    0.571131] target for CPU 2: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.571131] cpufreq: governor: change or update limits
[    0.571132] cpufreq: __cpufreq_governor for CPU 2, event 3
[    0.571133] target for CPU 2: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.571133] cpufreq: initialization complete
[    0.571134] cpufreq: adding CPU 3
[    0.571135] acpi_cpufreq_cpu_init
[    0.571176] HARDWARE addr space
[    0.571177] get_cur_freq_on_cpu (3)
[    0.571227] get_cur_val = 9472
[    0.571227] cur freq = 3401000
[    0.571228] CPU3 - ACPI performance management activated.
[    0.571229]      *P0: 3401 MHz, 77000 mW, 10 uS
[    0.571229]       P1: 3400 MHz, 77000 mW, 10 uS
[    0.571230]       P2: 3300 MHz, 73840 mW, 10 uS
[    0.571231]       P3: 3100 MHz, 67694 mW, 10 uS
[    0.571232]       P4: 3000 MHz, 64705 mW, 10 uS
[    0.571233]       P5: 2900 MHz, 61772 mW, 10 uS
[    0.571233]       P6: 2800 MHz, 58907 mW, 10 uS
[    0.571234]       P7: 2600 MHz, 53315 mW, 10 uS
[    0.571235]       P8: 2500 MHz, 50601 mW, 10 uS
[    0.571236]       P9: 2400 MHz, 47940 mW, 10 uS
[    0.571236]       P10: 2200 MHz, 42787 mW, 10 uS
[    0.571237]       P11: 2100 MHz, 40284 mW, 10 uS
[    0.571238]       P12: 2000 MHz, 37833 mW, 10 uS
[    0.571251]       P13: 1900 MHz, 35433 mW, 10 uS
[    0.571252]       P14: 1700 MHz, 31421 mW, 10 uS
[    0.571253]       P15: 1600 MHz, 29164 mW, 10 uS
[    0.571258] cpufreq: setting new policy for CPU 3: 1600000 - 3401000 kHz
[    0.571258] acpi_cpufreq_verify
[    0.571259] acpi_cpufreq_verify
[    0.571260] cpufreq: new min and max freqs are 1600000 - 3401000 kHz
[    0.571260] cpufreq: governor switch
[    0.571261] cpufreq: __cpufreq_governor for CPU 3, event 4
[    0.571261] cpufreq: __cpufreq_governor for CPU 3, event 1
[    0.571262] target for CPU 3: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.571263] cpufreq: governor: change or update limits
[    0.571263] cpufreq: __cpufreq_governor for CPU 3, event 3
[    0.571264] target for CPU 3: 3401000 kHz, relation 1, requested 3401000 kHz
[    0.571264] cpufreq: initialization complete
[    0.571266] cpufreq: driver acpi-cpufreq up and running

Core 0 reports its frequency to be 3400000, the highest non-turbo
frequency and is correctly set to 3401000.
The log seems to indicate that CPU 1, 2 and 3 are already at 3401000
(the turbo frequency enabler) but this must be incorrect because they do
not scale to 3.8GHz when stressed.
Presumably reverting the previously discussed patch makes it work
because it sets it to 3401000 regardless of what the previous frequency
claims to be.

Hmmm, now to find out why those values are reported incorrectly...

Thanks for the help,
-- 
Ross Lagerwall