Re: Scaling governors in 14.1 stock kernel

On Wed, Nov 13, 2013 at 10:12:35AM +0000, David Woodfall wrote:
> I noticed that both my server and laptop have powersave as scaling
> governor, and the choices available are that and performance.
> 
> Can you guys take a look at the output of
> 
> cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
> 
> please?

Does dmesg have lines like "Intel pstate controlling: cpu 0"? The
config file has "CONFIG_X86_INTEL_PSTATE=y", so it doesn't use the
traditional cpufreq drivers at all. Look at the three files under
/sys/devices/system/cpu/intel_pstate
You can control the intel_pstate driver by echoing values there.

      max_perf_pct: limits the maximum P state that will be requested by
      the driver stated as a percentage of the avail performance.
    
      min_perf_pct: limits the minimum P state that will be requested by
      the driver stated as a percentage of the avail performance.
    
      no_turbo: limits the driver to selecting P states below the turbo
      frequency range.

If you echo performance to scaling_governor, then the three files
above contain 100, 100, and 0. The default (powersave) has a lower
minimum P state, so it can lower the frequency.