Update on DeviceKit

[Holger Macht]

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_.

Regards,
	Holger