Re: kernel vs user power management
Holger Macht <hmacht <at> suse.de>
2006-04-10 08:35:45 GMT
On Sat 08. Apr - 23:06:54, Brown, Len wrote:
> >On Sat 08. Apr - 02:42:12, Brown, Len wrote:
> >> Timo, Holger,
> >> Andi pointed me to your FOSDEM Linux Power Management presentation:
> >> http://en.opensuse.org/FOSDEM2006
> >> http://files.opensuse.org/opensuse/en/b/b5/One_step_opendesign.pdf
> >> And I'm glad to see you working on Linux Power Management.
> >> But I'm a little concerned that user-space and the kernel are
> >> a little out of sync on a few things.
> >> I'm happy to see that the userspace p-state governor
> >> is no longer enabled by default on SuSE systems.
> >> While it was passable on servers with steady-state
> >> workloads, it was very bad for laptops where the
> >> machine spends a lot of time idle, but has short
> >> bursts of processing need which userspace could
> >> not detect. These laptops would spend virtually
> >> all their time in Pn when using the userspace governor.
> >To be honest, this observation suprises me a little bit. We did some
> >measurements with userspace agains ondemand governor some time
> >ago and did not notice any big differences in the results between them.
> >Well, these tests are about 1 1/2 years ago, though, and there went some
> >changes into the kernel until now
> Yes, measurements show that ondemand as improved