The performance governor for cpufreq doesn't seem to behave as adverti
The kernel in use: 3.2.0-23-generic on Ubuntu 12.04LTS
For example, I issue the following command:
Then I go to /sys/devices/system/cpu/cpu0/cpufreq and type in the following:
sudo cpufreq-set -c 0 -g performance
Sometimes I get the max frequency (3600 MHz) when I do this and sometimes I get the min frequency (1600 MHz).
sudo cat cpuinfo_cur_freq
If I do:
The output is performance, showing that the governor is in fact set to performance.
Then, to make it even more weird, if I do:
If you look at the current policy above, you will notice that it is telling me that the CPU should be pegged at 3.60 GHz. Yet, polling (i.e., displaying) cpuinfo_cur_freq once a second seems to tell a different story.
analyzing CPU 0:
CPUs which run at the same hardware frequency: 0 1 2 3 8 9 10 11
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 10.0 us.
hardware limits: 1.60 GHz - 3.60 GHz
available frequency steps: 3.60 GHz, 3.60 GHz, 3.47 GHz, 3.33 GHz, 3.20 GHz, 3.07 GHz, 2.93 GHz, 2.80 GHz, 2.67 GHz, 2.53 GHz, 2.40 GHz, 2.27 GHz, 2.13 GHz, 2.00 GHz, 1.87 GHz, 1.73 GHz, 1.60 GHz
available cpufreq governors: conservative, ondemand, userspace, powersave, performance
current policy: frequency should be within 3.60 GHz and 3.60 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 3.60 GHz.