pstate Intel driver pisses me off for good, because they have removed the good old
powersave governor that allowed me to set the lowest available CPU frequency and run my numerical simulations for hours or days in a nicely silent, cold laptop. To make things worse, what they call now
powersave is essentially the old governor
ondemand, i.e. a mode in which the CPU frequency rams up with the load, and with it the damn fan noise:
Since these policies are implemented in the driver, they are not same as the cpufreq scaling governors implementation, even if they have the same name in the cpufreq sysfs (scaling_governors). For example the "performance" policy is similar to cpufreq(TM) "performance" governor, but "powersave" is completely different than the cpufreq "powersave" governor. The strategy here is similar to cpufreq "ondemand", where the requested P-State is related to the system load.
(Extracted from https://www.kernel.org/doc/Documentation/cpu-freq/intel-pstate.txt)
Now, please, is there any other way to keep my CPU frequency at a minimum? It's really important for me. I just prefer to dump the laptop through the window if I eventually cannot set a constant, lowest CPU frequency. That is how I use my laptop and that is what I want a laptop for, and I have been trying to achieve this for several days already!
I'm trying this, and it doesn't work:
echo 42 | sudo dd of=/sys/devices/system/cpu/intel_pstate/max_pref_pct
to set the maximum speed at 42%, and it doesn't have any affect, the CPU keeps on going to 100% whenever I do something. What am I doing wrong? (should I restart some service or something?)
Is there any way to get this? Also, will a non-Intel CPU allow me to do that? I don't mind buying another laptop it that is going to solve the problem.