RFC: powerd algorithms enhancements

[Alexander Motin]

Nate Lawson wrote:
> Alexander Motin wrote:
>> 2. To make powerd's operation independent from number and size of
>> frequency levels I have added internal frequency counter which
>> translated into real frequencies only on a last stage and only as good
>> as gone. Some systems may have only several power levels, while mine has
>> 17 of them, so adaptation time in completely different. It would be good
>> if algorithm was not depending on it.
> 
> I don't understand the advantage of this.

Universality and predictiveness. Systems with 2 and with 32 levels will 
drop/rise frequency with same absolute rate. If we are trying to speak 
about some comparing, algorithm should be hardware independent.

> There's a patch Cyrille Szymanski has sent me to review that implements
> the FLAT and PAST algorithms in powerd.  I think we should not add new
> modes that are heuristics (including this one) until we have a chance to
> compare it to algorithms that have been the result of real research.

So show it to us. This area is heuristic by default as there is several 
opposite criteriums, so any algorithm will be heuristic.

-- 
Alexander Motin