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This is one of a number of pages about installing Kubuntu Linux on a Sony TX1XP laptop. To see the other pages go here
as root, or via sudo
$ cat /proc/acpi/processor/CPU0/throttling
state count: 8
active state: T0
states:
*T0: 00% <-- no throttling
T1: 12%
T2: 25%
T3: 37%
T4: 50%
T5: 62%
T6: 75%
T7: 87% <-- max throttling
to change state (again as root or via sudo)
echo 4 > /proc/acpi/processor/CPU0/throttling
will shift you into state 4, and throttle your cpu by 50%. Exactly what that means I am not sure, but a very simple test using the following perl script:
for (my $i = 0; $i < 1000000; $i++) { $x = 67 * 68 / 4; }
shows that the script runs about twice as fast at state 0 (no throttling) as when in state 4 (50% throttling).
At state 7 (87% throttling) evening issuing an "ls" command in konsole appears to take a few seconds to complete. I've not yet tested to see how throttling might effect battery life - anyone with stats to report, please email (address at the bottom of the page).
I've since learned that CPU throttling is not considered best practise. I'm not sure either way, but apparently it is better to adjust the trigger points (aka temps) at which the system should adjust the CPU power and let it handle all this itself. Namely, let the system throttle, don't do it yourself manually.
All well and good, except I have yet to figure out how to adjust the temperature trigger points such that the system does do the adjustment itself, and also if you are on a long (plane/train) trip without power, you might want to forcefully throttle the CPU to reduce battery consumption.
Anyway...