Re: CPU frequency and custom kernel

[Sean Alexandre <sean@alexan.org>]

On Fri, Nov 22, 2013 at 11:06:14AM +0100, Jochen Spieker wrote:
> Check the files in this directory:
> 
> /sys/devices/system/cpu/cpu0/cpufreq
> 
> Especially scaling_available_frequencies, scaling_max_freq and
> scaling_min_freq.

I've been using the cpufreq-info, which I think reports what's in those files.
For the Debian kernel I get:

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us.
  hardware limits: 800 MHz - 2.30 GHz
  available frequency steps: 2.30 GHz, 2.00 GHz, 1.80 GHz, 1.60 GHz, 1.40 GHz, 1.20 GHz, 1000 MHz, 800 MHz
  available cpufreq governors: conservative, powersave, userspace, ondemand, performance
  current policy: frequency should be within 800 MHz and 2.30 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 800 MHz (asserted by call to hardware).
  cpufreq stats: 2.30 GHz:5.20%, 2.00 GHz:0.14%, 1.80 GHz:0.16%, 1.60 GHz:0.20%, 1.40 GHz:0.28%, 1.20 GHz:0.44%, 1000 MHz:0.49%, 800 MHz:93.09%  (39552)

And then for the custom kernel I get:

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us.
  hardware limits: 800 MHz - 2.30 GHz
  available frequency steps: 2.30 GHz, 2.00 GHz, 1.80 GHz, 1.60 GHz, 1.40 GHz, 1.20 GHz, 1000 MHz, 800 MHz
  available cpufreq governors: conservative, powersave, userspace, ondemand, performance
  current policy: frequency should be within 800 MHz and 2.30 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1.80 GHz (asserted by call to hardware).
  cpufreq stats: 2.30 GHz:11.32%, 2.00 GHz:1.27%, 1.80 GHz:0.94%, 1.60 GHz:0.59%, 1.40 GHz:1.17%, 1.20 GHz:0.60%, 1000 MHz:1.12%, 800 MHz:82.99%  (713)

That last line for the custom kernel says the CPU runs at 800 MHz most of the time, 
but I think that's because the stats don't roll over on reboot. It shows I'm using 
the Debian kernel most of the time.