Re: cpufreq and p4 prescott

[Rutger Nijlunsing]

> > The only thing I could find in Intel's documentation is the max. time
> > of throttling is 3 microseconds (p.67; 5.2.1 of Prescott
> > datasheet). So this 3 microseconds should correspond to 5600 ticks or
> > so...
> 
> Can't find it in the datasheets right now, but did find an interesting
> comment in section 13.15.3 of 24547212.pdf which explains the strange
> behaviour we're seeing.

Hm, 13.16.3 in my version, but indeed: all logical processors should
be put asleep in the same way ;)

> 
> > I know this is not P4 specific, but motherboard specific, but do
> > you know of modules which use motherboard specific knowledge to scale
> > the processor?
> No.
> > If the BIOS can do it, so should we be able to do it.
> 
> Dynamic frequency scaling is (probably) way different from setting a
> frequency at boot (which is what the BIOS does). Timing issues, settling
> times, etc. are way too complicated, AFAICS. Even trying to do this might
> result in severe non-recoverable hardware failures.

Probably true for some motherboards, but Asus got a WinXP program
called 'AiBooster' which is a program to under/overclock from -50% to
+33% runtime (butt-ugly UI can be seen in
http://www.asuscom.de/pub/ASUS/mb/sock478/p4p800/AIBooster_u.pdf). Could
Wine be used (given the right permissions) to run or disect such a
utility to make underclocking reality under Linux?

*hopeful* Or has Asus released the specification of its motherboard?

-- 
Rutger Nijlunsing ---------------------------- rutger ed tux tmfweb nl
never attribute to a conspiracy which can be explained by incompetence
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