Alexander Meyer (ali@...) scribbled:
> On Mi, Jun 29 2005 at 01:32:29 +0200, Colin Leroy wrote:
> > On Wed, 29 Jun 2005 12:27:39 +0200
> > Alexander Meyer <ali@...> wrote:
> > 
> > > Well, if there's no means to control when the fan starts it probably
> > > _is_ something like this. i'll try some earlier 2.6 kernels then since
> > > Stefan earlier stated that this change didn't occur at the 2.4->2.6
> > > switch but somewhere in the early 2.6 series (IIRC before 2.6.7).
> > > i'm hardly using the machine anymore because that goddamn fan is just
> > > too annoying and if i try to compensate by turning up my music the
> > > neighbors will complain after a while ;(
> > 
> > May be due to the defaut HZ value change.
> 
> Now _that_ is strange: I recently changed that back from 1000 to 100 but
> with no visible (or audible that is) effect whatsoever.
> 

This is correct behavior.  The value of HZ defines the minimum
resolution of system calls like usleep() and select().  At 100Hz, the
minimum resolution is ~20ms (= 2 * 1 / f) for usleep and ~10ms (= 1 / f)
for select().  Setting it to 1000Hz adjusts those values down to ~2ms
and ~1ms respectively.  I've only found this useful with old/half-assed
code that polls interfaces.  They'll use usleep() to throttle the
polling and not max out the CPU.

But that is background info, the main point is that it has no effect on
power consumption.

Do your system monitors (gkrellm, top, whatever) show a maxed out cpu?

Cooper.
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