# Intel CPU Power Management

## Buffoon

So I enabled Intel P-State driver in kernel along with performance and powersave governors. After reading this. Now conky is showing 3.7 GHz at all times. I wonder what is really going on, is my CPU power and frequency managed properly or not? It is sixth gen i3.

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## Logicien

At boot, the kernel use the default governor as it is configure. It will not change governor by itself. You need utilities like cpufrequtils and cpupower to change the governor as a boot service. Some utilities can change the governor on the fly depending on several criterias. Othewise, the kernel stay using the default governor.

I don't know Conky but, if it can change the govervor, the appropriate modules must be load to do so if not in the kernel image itself.

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## Buffoon

Thanks, but frankly, I do not think this is how P-States driver works. What you describe is older ACPI implementation.

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## Roman_Gruber

I use the tool called i7z to check the cpu states and frequency / turbo in use.

+ htop / top

the intel data sheet of your cpu will reveal the supported features of the cpu. 

e.g. for myself: http://ark.intel.com/products/64899/Intel-Core-i7-3610QM-Processor-6M-Cache-up-to-3_30-GHz

--

```
cpupower frequency-set -g powersave

Setting cpu: 0

Setting cpu: 1

Setting cpu: 2

Setting cpu: 3

Setting cpu: 4

Setting cpu: 5

Setting cpu: 6

Setting cpu: 7

ASUS-G75VW roman # 

```

powersave or performance ... there may be other options though.

or

-f frequency

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## Ant P.

With this driver the cpuidle numbers are more meaningful than cpufreq ones. powertop or cpupower will show you if it's working or not.

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## Buffoon

So what you make out of this output? I understand the CPU should manage itself in most part? True?

```
~ # cpupower frequency-info

analyzing CPU 0:

  driver: intel_pstate

  CPUs which run at the same hardware frequency: 0

  CPUs which need to have their frequency coordinated by software: 0

  maximum transition latency:  Cannot determine or is not supported.

  hardware limits: 800 MHz - 3.70 GHz

  available cpufreq governors: performance powersave

  current policy: frequency should be within 800 MHz and 3.70 GHz.

                  The governor "performance" may decide which speed to use

                  within this range.

  current CPU frequency: 3.70 GHz (asserted by call to hardware)

  boost state support:

    Supported: no

    Active: no

```

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## Roman_Gruber

I have an ivybridge i7-3610qm cpu.

Maybe you should try   driver: acpi-cpufreq + MAy i kindly ask you to try out i7z package please?

```
cpupower frequency-info 

analyzing CPU 0:

  driver: acpi-cpufreq

  CPUs which run at the same hardware frequency: 0

  CPUs which need to have their frequency coordinated by software: 0

  maximum transition latency: 10.0 us

  hardware limits: 1.20 GHz - 2.30 GHz

  available frequency steps:  2.30 GHz, 2.30 GHz, 2.20 GHz, 2.10 GHz, 2.00 GHz, 1.90 GHz, 1.80 GHz, 1.70 GHz, 1.60 GHz, 1.50 GHz, 1.40 GHz, 1.30 GHz, 1.20 GHz

  available cpufreq governors: conservative userspace powersave ondemand performance

  current policy: frequency should be within 1.20 GHz and 2.30 GHz.

                  The governor "powersave" may decide which speed to use

                  within this range.

  current CPU frequency: 1.20 GHz (asserted by call to hardware)

  boost state support:

    Supported: yes

    Active: yes

    3100 MHz max turbo 4 active cores

    3100 MHz max turbo 3 active cores

    3200 MHz max turbo 2 active cores

    3300 MHz max turbo 1 active cores

```

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## Buffoon

I will as soon as I get home. Thanks.

According to this I did everything right. It is just not working.

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## Ant P.

 *Buffoon wrote:*   

> So what you make out of this output?

 

All looks correct. If you set it to powersave governor you should see it at 800MHz most of the time. `cpupower monitor` gives better details because it shows how much the hardware is powered down (i.e. various degrees of "0 MHz")

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## Buffoon

I'm confused. Probably need to sleep on it and try to wrap my head around it tomorrow with fresh caffeine.

 *Quote:*   

> Understanding the cpufreq core governors and policies are important before
> 
> discussing more details about the Intel P-State driver. Based on what callbacks
> 
> a cpufreq driver provides to the cpufreq core, it can support two types of
> ...

 

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