RE: [PATCHSET] 0/3 Dynamic cpufreq governor and updates to ACPI P-state driver

From: Pallipadi, Venkatesh
Date: Tue Oct 21 2003 - 20:44:35 EST




> -----Original Message-----
> From: linux-kernel-owner@xxxxxxxxxxxxxxx
> [mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Måns Rullgård
>
> So, how does this work? I'd like to be able to set minimum and
> maximum clock frequencies to allow, and CPU utilization thresholds at
> which to switch frequencies. Is that possible, or is it work yet to
> be done? Adjustable polling interval would also be nice.
>

Yes. You can set the maximum and minimum allowed frequencies using
the standard cpufreq interface. Something like:
echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

However, other interfaces to tune this particular governor is not
there yet. Other tunables that will be exported to user in future are
Polling interval and CPU utilization thresholds.

> > The patches will work on all laptops with EST technology
> > (Centrino) and also on any other system that supports low
> > latency frequency change.
>
> Does Pentium 4 M work?

AFAIK, P4M does not support EST. You can double check with
/proc/cpuinfo and look out for EST flag.


Thanks,
-Venkatesh
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