Re: [PATCH 0/6] cpufreq: Add sampling window to enhance ondemand governor power efficiency

Dominik Brodowski
2010-12-23T21:08:55Z

Hey,

On Thu, Dec 23, 2010 at 12:34:02PM -0500, Dave Jones wrote:
> On Thu, Dec 23, 2010 at 12:00:20PM +0100, Dominik Brodowski wrote:
> > Interesting approach, but seems to be quite different from what "ondemand"
> > does at the moment. And, as David Niemi pointed out, it seems to be more
> > Intel-specific. Therefore, what do you think about adding this different
> > algorithm as a different governor, and keep the "ondemand" algorithm more or
> > less as it is?
>
> I'm hesitant to merge more governors. (We already have too many imo).

AFAICS, we do have two in-kernel dynamic frequency scaling governors, one of
which doesn't seem to get much usage (conservative)...

> The userspace logic for automatically deciding which is the best one to use is
> already pretty hairy, so any additional ones at this point would have to be
> accompanied with some really compelling reasons why the existing ones can't
> be fixed in an acceptable manner.

Well, if the underlying alogrithm is fundamentally different -- such as when
looking at sampling windows instead of the past one window -- this seems to
be a "compelling" reason to me. Especially if one governor works well on
certain platforms, and the other one works better on other platforms.

Best,
Dominik