[PlanetCCRMA] governor issue w/ rt kernel

[Fernando Lopez-Lezcano]

On 01/10/2015 11:12 AM, Ben Breard, Jr. wrote:
> Hey guys,
>
> I'm having an issue with F21 and
> kernel-rt-3.14.25-200.rt22.1.fc21.ccrma.x86_64. Basically only the
> powersave governor seems to work. On a regular F21 kernel my system is
> configured with "performance", but when I boot into the latest rt
> kernel, not only does it default to powersave, I'm unable to change it
> to performance.
>
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors shows
> both the performance and powersave governors available, but changing it
> via echoing the value into /sys, using cpupower, and tuned-adm all fail.
>
> Is anyone else seeing this, or do you think I'm doing something wrong?

You are doing nothing wrong. For newer intel cpus and recent kernels 
there is a new speed control system in the kernel, the driver is 
intel_pstate and it is controlled differently. You can achieve pretty 
much the same effect as with the old "performance" governor by typing:

echo "100" > /sys/devices/system/cpu/intel_pstate/min_perf_pct

This forces all cores to (try to) run at top speed all the time. You 
will not see the exact same numbers on all cores as before but this 
works for me.

Some information here:
https://www.kernel.org/doc/Documentation/cpu-freq/intel-pstate.txt
and here:
https://wiki.archlinux.org/index.php/CPU_frequency_scaling

> I love this repo thank you for continuing to make Fedora a great
> platform for music production!

Glad to hear it is working for you!
-- Fernando