Re: [PATCH 3/3] PM: Introduce Intel PowerClamp Driver

From: Arjan van de Ven
Date: Tue Nov 13 2012 - 16:56:35 EST


On 11/13/2012 1:16 PM, Paul E. McKenney wrote:
> On Mon, Nov 12, 2012 at 02:03:51PM -0800, Jacob Pan wrote:
>> Intel PowerClamp driver performs synchronized idle injection across
>> all online CPUs. The goal is to maintain a given package level C-state
>> ratio.
>>
>> Compared to other throttling methods already exist in the kernel,
>> such as ACPI PAD (taking CPUs offline) and clock modulation, this is often
>> more efficient in terms of performance per watt.
>>
>> Please refer to Documentation/thermal/intel_powerclamp.txt for more details.
>
> If I read this correctly, this forces a group of CPUs into idle for
> about 600 milliseconds at a time. This would indeed delay grace periods,

6ms not 600


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