Making ‘ondemand’ CPU frequency scaling more responsive
Tuesday, May 12th, 2009For a while now I’ve found that ondemand CPU frequency scaling (enabled by default) makes my laptop seem sluggish under Ubuntu.
Basically the CPU speed doesn’t seem to increase quickly enough to keep up with the sudden brief bursts of demand caused when using Gmail, or playing Youtube videos for instance. Applying information found on this website seems to give a more responsive system.
echo 1 > /sys/devices/system/cpu/cpu0/cpufreq/ondemand/ignore_nice_load
echo 40 > /sys/devices/system/cpu/cpu0/cpufreq/ondemand/up_threshold
This changes the default behaviour of the ondemand governor to force it to take into account background processes, and tells it to increase CPU speed when your CPU usage exceeds 40% rather than 95% (as is default).
Because /sys/ is a virtual file system created each time you boot your system, any changes you make are lost after a restart. Add the lines above to /etc/rc.local (read here for more on rc.local) to have your chosen settings applied each time you start Ubuntu.
Have fun.
