Re: [PATCH 0/3] cpufreq: Replace timers with utilization update callbacks

From: Rafael J. Wysocki
Date: Thu Feb 11 2016 - 12:34:13 EST


On Thu, Feb 11, 2016 at 6:30 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Thu, Feb 11, 2016 at 09:06:04AM -0800, Steve Muckle wrote:
>> Hi Peter,
>>
>> >> > I think additional hooks such as enqueue/dequeue would be needed in
>> >> > RT/DL.
>
> That is what I reacted to mostly. Enqueue/dequeue hooks don't really
> make much sense for RT / DL.
>
>> Rafael's changes aren't specifying particular frequencies/capacities in
>> the scheduler hooks. They're just pokes to get cpufreq to run, in order
>> to eliminate cpufreq's timers.
>>
>> My concern above is that pokes are guaranteed to keep occurring when
>> there is only RT or DL activity so nothing breaks.
>
> The hook in their respective tick handler should ensure stuff is called
> sporadically and isn't stalled.

I've updated the patch in the meantime
(https://patchwork.kernel.org/patch/8283431/).

Should I move the RT/DL hooks to task_tick_rt/dl(), respectively?

Thanks,
Rafael