Ubuntu – Disable CPU frequency scaling on Lenovo Laptop

cpu loadcpufreqfrequencyscaling

I have a bug where my CPU frequency is scaling down every few hours or so. This happens when:

I'm on AC power
scaling governor is on 'Performance'

What do you have to do to disable CPU frequency scaling? I know you can manually force the min CPU frequency uder /sys/devices/system/cpu, however I really want a permanent solution so I don't have to be constantly changing the CPUfreq values.

Best Answer

Just to make sure it's not going to interfere, remove the powernowd package from your system. From a terminal, run:

sudo apt-get remove powernowd

After that, or if you don't have that package installed, install rcconf by running:

sudo apt-get install rcconf

Then run sudo rcconf and press space with the ondemand service highlighted to disable it. This service controls CPU frequency scaling. Press enter to save and quit. To manually stop it once, you can run sudo /etc/init.d/ondemand stop.

Related Solutions

Ubuntu – Ubuntu 13.04 CPU frequency scaling ‘stuck’ on lowest frequency

I had the same issue on latest version of Mint, setting the scaling to conservative seemed to be the closest to how ondemand used to work.

Then I found out what the problem was, the up_threshold was way too high, it was set to 95% load, now this is fine for continued loads, but in most cases there is a small burst of CPU activity, and you want the CPU to scale to 100% speed much faster. I resolved this by setting th up_threshold lower (75 seems to do OK in my case). You change it by echo'ing the desired value to /sys/devices/system/cpu/cpufreq/ondemand/up_threshold.

Ubuntu – CPU frequency scaling issue – scaling_max_freq wrong

OK, after few days of work, I think I can say this issue is solved ->
Use governor conservative and reset the scaling_max_freq as follow (if it changed):

(to do for each core)

echo conservative > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor  
echo 2530000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

The issue comes from the governor ondemand. After few seconds in high loads, it, somehow, reset the value of scaling_max_freq to 1520400 which become read-only or at least, can't be modified under "ondemand" governance and the CPU get stuck at the lowest frequency. I can reproduce the behavior.

Unfortunately, cpufreq-utils can't help (eg:/etc/init.d/cpufrequtils) and I can't set these values at boot time (eg: /etc/rc.local 0555'd), I have to apply it through a script with a cron job.

Where should I inform of this bug?

Best Answer

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Ubuntu – Ubuntu 13.04 CPU frequency scaling ‘stuck’ on lowest frequency

Ubuntu – CPU frequency scaling issue – scaling_max_freq wrong

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