[TriLUG] CPU speed and custom kernel

[Sean Alexandre]

On Thu, Nov 21, 2013 at 02:01:15PM -0500, Bill Farrow wrote:
> Have you compared your kernel config file with the debian kernel's one ?
> Are you building the cpufreq module for your cpu type ?
> Have you poked around inside /sys/devices/system/cpu/cpu0/cpufreq/ ?

I've been using the output from cpufreq-info, which I think reports what those
files have. For the Debian kernel I see:

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq at 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 see:

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq at 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)

I think the last line for the custom kernel is wrong ("stats"). It says the CPU
runs at 800 MHz most of the time, but I never see 800 MHz for "current CPU
frequency".  It's always at least 1.80 GHz (and the fan is quite a bit louder.)