View the actual frequency and change CPU frequency governor from gnome shell.
There is a bit of work to make it work though.
You need CPU Frequency scaling set up to use it.
Ubuntu 17.x: sudo apt-get install cpufrequtils
When the extension sets a governor, it does it one by one, calling cpufreq-selector for every cpu.
The problem here is that it will raise a popup asking for your password for each cpu. Typing the password for 4 CPUs can become quite annoying.
To solve this, I use (in archlinux):
Create and edit the file: /var/lib/polkit-1/localauthority/50-local.d/org.gnome.cpufreqselector.pkla
with:
[org.gnome.cpufreqselector]
Identity=unix-user:USER
Action=org.gnome.cpufreqselector
ResultAny=no
ResultInactive=no
ResultActive=yes
replacing USER with your username.
https://github.com/nodefourtytwo I based this on his work I'm gonna improve it in the future.
https://github.com/Farsx
https://github.com/LeCoyote
https://github.com/victornoel
https://github.com/sonic414