Re: Centrino not scaling to lowest frequency

[Dominik Brodowski <linux-X3ehHDuj6sIIGcDfoQAp7OTW4wlIGRCZ@public.gmane.org>]

On Thu, Aug 25, 2005 at 05:04:50PM +0200, Felix Homann wrote:
> On Wednesday 24 August 2005 12:50, Dominik Brodowski wrote:
> > That's because other Operating Systems do "throttling" on top of "CPU
> > frequency scaling", even though that doesn't save you any energy. The
> > better energy usage rates of Windows are a known problem; hopefully the
> > dynamic tick patch will improve the situation in this regard.
> >
> > 	Dominik
> >
> 
> Thanks for the info. The dynamic tick patch sounds really interesting! I'll 
> give it a try.
> 
> BTW, Intel's CPU identifiction utility reports a system bus frequency of 400 
> MHz when the CPU is reported to work at 600 MHz. Usually the system bus is 
> running at 533 MHz. Is this the effect of "throttling" on top of "CPU 
> frequency scaling" or is this something different?

Uh, this is strange. I know of no implementation on Intel CPUs to scale the
system bus frequency.

However.... Are you relying on centrino-decode of cpufrequtils? IIRC
it is broken for the 533 MHz case, so if it reports 400 MHz it actually means
600 MHz.  *clicketiclick* Yes, cpufrequtils-0.3 still contains this bug;
need to release 0.4 soon.

	Dominik


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