04 December, 2006

CPU Scaling

And more
Thanks to Larry Reeder

When I got my 600m, the CPU speed never went above 600 MHz, as shown by cat /proc/cpuinfo, or Gnome's CPU Frequency Scaling applet. I couldn't set the CPU frequency manually, and it wouldn't go up automatically when I was doing a long build. I was beginning to think that the 600m in "Inspiron 600m" stood for 600 MHz.

I was getting a "No speed steps could be determined" error every time I tried to run /etc/init.d/cpuspeed. After trying many things, I noticed that both scaling_max_freq and scaling_min_freq in /sys/devices/system/cpu/cpu0/cpufreq were set to 600000 (600 MHz).

I did: echo 2100000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq and then /etc/init.d/cpuspeed restart

After that the CPU would throttle up to meet demand, and I could also change the speed manually with the Gnome CPU frequency applet.
If you're trying to set various cpuspeed options, I recommend running the commands in /etc/init.d/cpuspeed manually, instead of using the cpuspeed script, which hides many possible error messages when the script has problems. Once you have the options you need, you can go back to using the cpuspeed script.

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