My experience with cpufreq in -STABLE
ducrot at poupinou.org
Wed Apr 6 07:01:10 PDT 2005
On Wed, Apr 06, 2005 at 08:49:15AM +0200, Frank Behrens wrote:
> Bruno Ducrot <ducrot at poupinou.org> wrote on 4 Apr 2005 19:17:
> > You may start looking at src/usr.sbin/powerd in -current, and improve it
> > a bit? The actual algorithm used in powerd may need some rework IMHO.
> Which problems do you see?
powerd use an exponentional decrease of the frequency. This might be
not stable for certain workload.
> My comments:
> 1. If the frequency is raised it should not go down immediately on
> short idle phases. To raise the frequency the current idle value
> should used but to lower the frequency we should calculate a weighted
> idle average value.
It might be a solution. It has been tested in that paper:
and it seems it's maybe not the better one, though (search 'MAW', its
exactly what you suggest).
> 2. The default polling time of 500 ms seems to be very short. It can
> increased to several seconds.
Problem if you increase teh polling intervall is that you can't be sure
that the system can detect in time when going up.
-- Which is worse: ignorance or apathy?
-- Don't know. Don't care.
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