A Qt version of gkrellm.
There are several ways to monitor the system performace on a Linux system. This includes console based applications like top, htop, free, df, and ps.
For graphical applications there are desktop based programs including gnome-system-monitor, qps (from LXQt), and plasma-systemmonitor.
The problem with the above programs is that they take up a lot of screen real estate. A grapical program that can run continuously but can be configured to use a small amount of screen space is GKrellM. See http://gkrellm.srcbox.net/
GKrellM is a powerful application, but it no longer seems to be maintained. It is gtk2 based and that has reached its end-of-life. There have been no substantial changes to the program since 2016.
sysmon-qt is a program similar to GKrellM but based on Qt6. It does not have all the capabilities of GKrellM, but provides the capability of monitoring CPU usage, memory use, and system temperatures. It is also highly configurable with the ability choose which items to monitor and what colors and fonts to use.
There are two versions of sysmon-qt in the repository. The qt5 branch uses qt5 libraries. The git HEAD uses qt6 libraries. The differences are relatively small and the functionality is the same.