Re: [gpm] New preferences UI

[Richard Hughes <hughsient gmail com>]

On Tue, 2006-12-19 at 00:16 +0100, Holger Macht wrote:
> On Mon 18. Dec - 21:12:13, Richard Hughes wrote:
> > On Mon, 2006-12-18 at 20:52 +0000, Matthew Garrett wrote:
> > > On Sat, Dec 16, 2006 at 01:58:19PM +0000, Richard Hughes wrote:
> > > > On Thu, 2006-12-14 at 21:16 +0000, Matthew Garrett wrote:
> > > > > Hi,
> > > > > 
> > > > > I've been playing with the new preferences UI in the 2.17 releases, and 
> > > > > so far I'm not especially keen.
> > > > 
> > > > Have a look that the attached image.
> > > 
> > > That's definitely better, but it still seems to have support for setting 
> > > the CPUfreq governer. On any modern hardware, what's the use case for 
> > > this being anything other than ondemand?
> > 
> > Well, I for one get a >200ms latency when I click the menus (i.e. less
> > snappy) when I'm scaled down to 1GHz - and I've noticed conservative and
> > ondemand take quite a while to "ramp up" when the cpu load goes up. Some
> > people might also not want the computer to scale at all.
> 
> As Mattthew already said, you shouldn't notice a significant amount of
> time when frequency increases. Otherwise there's definitely something
> wrong on your machine ;-)

Hmm. Maybe it's my brain playing to a preconceived idea. :-)

> > Maybe these are all just excuses - maybe we should just say
> > "ondemand" (or conservative if available) for battery power, and
> > "performance" on AC. It would sure make the difficult to explain problem
> > option in the UI unnecessary.
> > 
> > What does everyone else think?
> 
> Using fixed frequency is always bad idea. That's why there's this
> 'performance setting' for all dynamic governors in the hal cpufreq
> addon. I think it's just enough to always use ondemand, with different
> performance settings for AC (e.g. 25) and battery (e.g. 75).

I didn't know you could adjust the ondemand or conservative schedulers.
What does the performance setting do?

> What I thought about for kpowersave was (not sure if I'll do it):
> 
>   Only show a slider for CPU policy
> 
>   1 --------------- 50 --------------- 100
> 
>   Everything between 2 and 99 just sets the performance setting for the
>   current dynamic governor. If the user sets it to 1, powersave governor
>   is used, if set to 100, performance governor is used.
> 
> But it should be completely fine to just always set the ondemand governor
> with predefined performance values. A gconf key would be fine, though.

Sure, that's the way I'm now erring.

> And please note, once in a while the conservative governor gets very bad
> press on the kernel lists. So in its current state, I discourage everybody
> to use it.

Ohh, right. I was under the impression that conservative was the same as
ondemand with a longer "hold time" after a high cpu load - how else is
it different?

Thanks for your advice.

Richard.