Update on DeviceKit
hmacht at suse.de
Thu May 8 06:40:07 PDT 2008
On Thu 08. May - 14:27:29, Matthew Garrett wrote:
> On Thu, May 08, 2008 at 03:04:36PM +0200, Holger Macht wrote:
> > On Thu 08. May - 13:35:11, Matthew Garrett wrote:
> > > I'm not convinced that fine tuning is something that can be done in a
> > > generic way. It's going to be kernel specific, and there's no sense in
> > > having it tweakable at a per-user level. Trying to fit it into any sort
> > > of dbus interface would basically just be exposing the sysfs interface
> > > over dbus, which doesn't sound like a great idea...
> > We're already doing this quite successful.
> > SetCPUFreqPerformance method abstracts all the different sysfs entries of
> > CPUFreq with one single setting (1 to 100, corresponding to the
> > performance you get).
> Well, yes, but what does that mean? You can't rate performance on a
> scale of 0-100 - there's multiple factors at play. Is performance a
> latency issue? A raw power one? What should the thresholds for ondemand
> be? If you're altering multiple factors, then for some workloads a
> higher value may yield lower performance. If you're only altering one
> factor, you may not be obtaining maximum performance for that power
> consumption. Trying to squash this into a linear scale doesn't work.
You always get more performance for the price of more power
consumption. And having less performance results in lower power
consumption and in a non ideal world, you might cope with more latency. At
least this should be the goal. How can you say it doesn't work? It _does_.
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