On Wed, Oct 23, 2024 at 3:04 PM Michael Kjörling wrote:
>
> On 23 Oct 2024 14:46 -0400, from e...@gmx.us (Eben King):
> > I have a variable-speed CPU. Normally the OS manages it. If I want to make
> > less heat inside the case, is it possible to cap it at a certain speed?
>
> CPU speed is controlled by the CPU frequency governor.
>
> Set /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor to
> "ondemand" or "conservative"
What kind of cpu does your system have?
Mine is an Intel and .. at least as far as I can tell, has only the
"performance" or "powersave" options:
$ sudo cpupower -c all frequency-info | grep 'governor'
available cpufreq governors: performance powersave
The governor "powersave" may decide which speed to use
available cpufreq governors: performance powersave
The governor "powersave" may decide which speed to use
available cpufreq governors: performance powersave
The governor "powersave" may decide which speed to use
available cpufreq governors: performance powersave
The governor "powersave" may decide which speed to use
available cpufreq governors: performance powersave
The governor "powersave" may decide which speed to use
available cpufreq governors: performance powersave
The governor "powersave" may decide which speed to use
> (the main difference is how quickly they
> react to load changes), and
> /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
> as desired. (Value in the latter is in Hz.) The
> "scaling_available_governors" and "scaling_available_frequencies"
> pseudo-files in the same directory are likely to be instructive.
>
> You can also set the governor to "powersave" to run the CPU at its
> minimum supported speed.
I think I've got the "powersave" govenor selected and the CPU
frequency does not stay at the minimum level:
$ cpufreq-info | grep "current CPU "
current CPU frequency is 800 MHz.
current CPU frequency is 800 MHz.
current CPU frequency is 800 MHz.
current CPU frequency is 800 MHz.
current CPU frequency is 800 MHz.
current CPU frequency is 800 MHz.
then in another window
$ while true; do : ; done
and all the cpus max out
$ cpufreq-info | grep "current CPU "
current CPU frequency is 4.10 GHz.
current CPU frequency is 4.00 GHz.
current CPU frequency is 4.00 GHz.
current CPU frequency is 4.00 GHz.
current CPU frequency is 4.00 GHz.
current CPU frequency is 4.00 GHz.
Regards,
Lee
