What is a "performance governor"?

[mexbass]

Just installing Ardour 6.9.
I am not a Ubuntu freak and do not understand this message:

!!! WARNING !!! - Your system seems to use frequency scaling.
This can have a serious impact on audio latency.
For best results turn it off, e.g. by choosing the ‘performance’ governor.

I have no idea what my system (Ubuntu 20.04.3) is using… what is frequency scaling? how/where should I choose a “performance governor”?

Regards
Michael

[peder (Peder Hedlund)]

It tells the CPU how and when to go to sleep, to save power, and when and how to wake up when it’s needed for work.

Start a Terminal and run
sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
to see which guvernor you’re using and

sudo -i
Nr=`nproc --ignore=1`; for var in `seq 0 $Nr` ; do echo "performance" > /sys/devices/system/cpu/cpu${var}/cpufreq/scaling_governor ; done

to change it to the performance one.

To reset it to the original governor you either reboot or replace “performance” in the command above with what you had originally; probably “ondemand”

[mexbass]

Thanks Peder,
The answer to

sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
is “powersave”. So nothing I would bother with. I guess I can work without any problem having “power save” active.
I know I should not to real time recordings though, while power save could trigger, but for editing it should be okay.
Regards
Michael

[LPJ]

I have tried the method recommended by Paul in the post below and it works perfectly.
I think it is more flexible and more elegant than the method I explained, so I have deleted my previous post.
Thanks Paul and Peder for explaining it.
Happy new year by the way!

[paul (Paul Davis)]

Just in case it helps someone, this is the script I use to switch between performance and on-demand frequency scaling. I am sure it could be much better. It does not require thermald, and is invoked with either no arguments to check the current setting, or with a single word that starts with either “p” (to switch to performance) or “o” (to switch to on-demand).

!/bin/sh

if [ $# != 1 ]
then
    echo -n "Current mode (CPU0 only): "
    cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
    exit 0
fi

case $1 in
    p*) echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ;;
    o*) echo ondemand | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ;;
    *) echo "unknown argument \"$1\". Ignored." ; exit 1 ;;
esac