CPU Frequency Scaling

[Arjan van de Ven]

On Mon, 2006-12-04 at 11:43 +0000, Richard Hughes wrote:
> On Mon, 2006-12-04 at 11:38 +0100, Thomas M Steenholdt wrote:
> > If the scaling governor is quick enough to detect the need and perform
> > the transition, most workloads....
> 
> I've had complaint, (and noticed myself) that conservative and ondemand
> often take a few hundred ms to "ramp up" to a suitable frequency.

again...
what is the bugzilla nr?

> Ordinarily this isn't a problem, but with my dual 1.6Ghz laptop idling
> down to 1Ghz, clicking 'Applications' doesn't feel as "snappy" as it
> should.

you as human don't notice the difference between 1000 and 1600 Mhz. This
has nothing to do with how snappy it feels.... This very very likely is
some other effect like pagefault misses etc.


> I guess it's a difficult balance between latency and smoothing to avoid
> changing the frequency too often

no it's not, it's most likely a case of nobody filing a bug or doing a
problem report....

in principle ondemand on Intel cpus can switch in like 10 usec. The rest
is software tuning.