[64studio-devel] Kernel 2.6.23 dynamic-speed

[joel silvestre]

Hi Daniel,


Le mercredi 17 octobre 2007 à 10:05 +0100, Daniel James a écrit :

> So does the CPU frequency drop on your laptop when RT tasks are running? 
> If so, we should take this problem upstream to Ingo Molnar.

The frequency doesn't drop but doesn't increase with cpu load.

> If not, then 
> that's a pretty cool feature, because it means you can potentially 
> extend battery life *and* keep your audio glitch-free.

As audio softwares have both RT and non RT tasks it doesn't prevent
frequency to change with non RT cpu load. 
You can ask Powersave daemon to do it more safely:

 CPUFreq modes:
   -f, --performance-speed                set cpufreq to performance
mode
   -l, --powersave-speed                  set cpufreq to powersave mode
   -A, --dynamic-speed                    set cpufreq to dynamic mode
   -c, --cpufreq-state-info               print out the current cpufreq
policy

Only the -A mode seems broken for RT task.


All the best,
Joel