Programmatically disable on Windows10 C3, C4, C5, C6 states of CPU

Question

Programmatically disable on Windows10 C3, C4, C5, C6 states of CPU

Jiří Mikeska 1

Good day.

I want to programmatically disable on Windows10 C3, C4, C5, C6 states of CPU. I tried this code:

   const GUID processor_idle_state_maximum = {0x9943e905, 0x9a30, 0x4ec1, 0x9b, 0x99, 0x44, 0xdd, 0x3b, 0x76, 0xf7, 0xa2};
   GUID *scheme;
   const DWORD DISABLED = 1;
   DWORD error;
   error = PowerGetActiveScheme(NULL, &scheme);
   error = PowerWriteACValueIndex(NULL, scheme, &GUID_PROCESSOR_SETTINGS_SUBGROUP, &processor_idle_state_maximum, DISABLED);
   error = PowerWriteDCValueIndex(NULL, scheme, &GUID_PROCESSOR_SETTINGS_SUBGROUP, &processor_idle_state_maximum, DISABLED);
   error = PowerSetActiveScheme(NULL, scheme);

But this does nothing (I checked it in PerfMon.exe). As value DISABLED I tried all possible values from 1 to 20.

And how to disable C2, C3, C4, C5, C6 states of CPU?

Castorix31 89,376 Reputation points

2023-03-12T21:32:52.5866667+00:00

It should be GUID_PROCESSOR_IDLE_DISABLE
Jiří Mikeska 1 Reputation point

2023-03-12T21:52:35.1933333+00:00

Guid PROCESSOR_IDLE_DISABLE disable ALL C-states and set CPU usage to 100% (I already know about this guid and test it). But I want to leave C1 and C2 states enabled as it in my question above.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2023-03-13T06:26:48.15+00:00

Does the question work for you? You can try PROCESSOR_POWER_POLICY.
Jiří Mikeska 1 Reputation point

2023-03-13T11:07:48.39+00:00

@Xiaopo Yang - MSFT

Regarding function WriteProcessorPwrScheme and similar:

"Starting with Windows Vista, power management configuration of the system's processor is controlled through the GUID_PROCESSOR_SETTINGS_SUBGROUP power settings subgroup."

See Remarks section here https://learn.microsoft.com/en-us/windows/win32/api/powrprof/nf-powrprof-writeprocessorpwrscheme

In my question is Windows 10.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2023-03-14T08:59:43.2633333+00:00

The most possible power setting guid I found is Processor performance core parking maximum and minimum cores.
Jiří Mikeska 1 Reputation point

2023-03-14T10:07:08.97+00:00

But this has nothing with C states of processor.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2023-03-29T02:23:25.3466667+00:00

Hello @Jiří Mikeska, I have consulted for this. You may turn to the hardware driver. Processor power management options don't involve in CPU C-states.

Your answer

Castorix31 89,376 Reputation points

2023-03-12T21:32:52.5866667+00:00

It should be GUID_PROCESSOR_IDLE_DISABLE
Jiří Mikeska 1 Reputation point

2023-03-12T21:52:35.1933333+00:00

Guid PROCESSOR_IDLE_DISABLE disable ALL C-states and set CPU usage to 100% (I already know about this guid and test it). But I want to leave C1 and C2 states enabled as it in my question above.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2023-03-13T06:26:48.15+00:00

Does the question work for you? You can try PROCESSOR_POWER_POLICY.
Jiří Mikeska 1 Reputation point

2023-03-13T11:07:48.39+00:00

@Xiaopo Yang - MSFT

Regarding function WriteProcessorPwrScheme and similar:

"Starting with Windows Vista, power management configuration of the system's processor is controlled through the GUID_PROCESSOR_SETTINGS_SUBGROUP power settings subgroup."

See Remarks section here https://learn.microsoft.com/en-us/windows/win32/api/powrprof/nf-powrprof-writeprocessorpwrscheme

In my question is Windows 10.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2023-03-14T08:59:43.2633333+00:00

The most possible power setting guid I found is Processor performance core parking maximum and minimum cores.
Jiří Mikeska 1 Reputation point

2023-03-14T10:07:08.97+00:00

But this has nothing with C states of processor.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2023-03-29T02:23:25.3466667+00:00

Hello @Jiří Mikeska, I have consulted for this. You may turn to the hardware driver. Processor power management options don't involve in CPU C-states.

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Programmatically disable on Windows10 C3, C4, C5, C6 states of CPU

Your answer