Install wmcpuload by entering the following commands in the terminal:
sudo apt update sudo apt install wmcpuload
Description:
Dockapp that displays the current CPU usage
WMCPULoad is a dockapp for X window managers such as WindowMaker, AfterStep, BlackBox and Enlightenment. It displays the current CPU usage as percentage value and chart with an LCD-like look. Its appearance can be configured from the commandline and it has a backlight mode which can be triggered manually or by an adjustable alarm percentage.
Homepage: http://www.dockapps.net/wmcpuload/
Version: 1.1.1-1
Section: universe/x11