Re: [PATCH V6] powercap/drivers/idle_injection: Add an idle injection framework

From: Daniel Lezcano
Date: Wed Jun 13 2018 - 16:00:47 EST


On 13/06/2018 17:54, Pandruvada, Srinivas wrote:
> On Tue, 2018-06-12 at 14:00 +0200, Daniel Lezcano wrote:
>> Initially, the cpu_cooling device for ARM was changed by adding a new
>> policy inserting idle cycles. The intel_powerclamp driver does a
>> similar action.
>>
>> Instead of implementing idle injections privately in the cpu_cooling
>> device, move the idle injection code in a dedicated framework and
>> give
>> the opportunity to other frameworks to make use of it.
>>
>> The framework relies on the smpboot kthreads which handles via its
>> main loop the common code for hotplugging and [un]parking.
>>
>> This code was previously tested with the cpu cooling device and went
>> through several iterations. It results now in split code and API
>> exported in the header file. It was tested with the cpu cooling
>> device
>> with success.
>>
> May be I have missed, but I don't see any use of powercap sysfs.
>
> We created powercap sys that user space is presented a common interface
> for power capping. The RAPL driver was also submitted as cooling device
> before, but suggestion was to create this powercap.
>
> So if powercap interface is not enough then may be we should enhance
> that.

We are creating a framework for idle injection. This framework can then
be used by the cpu_cooling device, the power_clamp and in addition a
power capping for ARM (if it makes sense).



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