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

[Dominik Brodowski <linux@brodo.de>]

On Tue, Oct 21, 2003 at 10:25:10AM +0200, Måns Rullgård wrote:
> "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> writes:
> 
> > Most of the latest CPUs (laptop CPUs in particular) have feature 
> > which enable very low latency P-state transitions 
> > (like Enhanced Speedstep Technology-EST). Using this feature, 
> > we can have a lightweight in kernel cpufreq governor, 
> > to vary CPU frequency depending on the CPU usage. The 
> > advantage being low power consumption and also cooler laptops.
> 
> So, how does this work?  I'd like to be able to set minimum and
> maximum clock frequencies to allow

echo "..." > /sys/devices/system/cpu/0/cpufreq/scaling_min_speed
echo "..." > /sys/devices/system/cpu/0/cpufreq/scaling_max_speed

>, and CPU utilization thresholds at which to switch frequencies.

select the demandbased governor

echo "demandbased" > /sys/devices/system/cpu/0/cpufreq/scaling_governor

and wait for the inclusion of a sysfs interface to the demandbased governor
which lets you override the current switching frequencies of 20% and 80%.

> Is that possible, or is it work yet to be done? 

Almost done.

> Adjustable polling interval would also be nice.

Should also be adaptable by sysfs. This sysfs interface really will be a
very useful addition, but it's not top priority.
 
	Dominik