Re: Alternative Concept [Was: Re: [RFC] CPUFreq PowerOP integration, Intro 0/3]

Matthew Locke
2006-10-17T21:40:59Z

On Oct 16, 2006, at 2:56 PM, Mark Gross wrote:

> On Thu, Oct 12, 2006 at 06:02:03PM +0200, Dominik Brodowski wrote:
>> Hi Mark,
>>
>> On Thu, Oct 12, 2006 at 08:38:21AM -0700, Mark Gross wrote:
>>>>> I think that this might be much easier to implement than your
>>>>> PowerOP /
>>>>> operating points / PM core / PowerOP - cpufreq interaction
>>>>> patches. As a
>>>>> matter of fact, some parts of your operating points table
>>>>> infrastructure
>>>>> may be usable for the concept outlined above. So, what do you
>>>>> think? What
>>>>> does everyone else involved think about this alternative approach?
>>>>
>>>> Looks okay to me. Unlike powerop design, this actually works for
>>>> everyone.
>>>
>>> Pavel, if you would pay attention better you would notice that at
>>> the
>>> underneath of what Dominic is talking about is a concept of *more
>>> knobs*
>>> for controlling platform power states. This is what PowerOP is
>>> trying
>>> to bring to the table.
>>
>> Oh no. PowerOP does it top->bottom; I try to do it bototm->top.
>> That's the
>> difference, and it is a _fundamental_ difference. Yes, both will
>> lead to a
>> concept of "operating points" on systems which may need it. But
>> still the
>> way you get there (which is important if you want to keep it
>> flexible, and
>> you do want to keep it flexible to allow for cpufreq) is different.
>
> I'll take a closer look at both. It really looks to me that folks
> are in
> violent agreement more than anything else. I also prefer a bottom-
> >top
> approach.

PowerOP has always exposed the power parameters to both kernel and
userspace. I think we can make some minor tweaks to the API as
Eugeny described in his email and we solve for both use cases
(embedded devices and x86 laptop/desktops).

>
> --mgross
>
>>
>>> PowerOP is not a policy engine like what Dominic is talking
>>> about. And
>>> what Dominic is talking about will need to build on something
>>> that will
>>> end up looking so much like power op that it wont be funny.
>>
>> This I dare to doubt.
>>
>> Thanks,
>> Dominik
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