The script calculates the CPU, Memory and I/O pressures by reading the PSI (Pressure Stall Information) provided by the Linux kernel. It should work with Linux kernel 5.2+, according to PSI by Example.
Example, returning the pressures every 0.5 seconds,
./psi-mon.py 0.5
It works well with Polybar. Just add the following to your Polybar config.
[module/psi-mon] type = custom/script tail = true exec = python -u ~/.local/share/polybar/psi-mon.py 0.5
It is important to pass -u option to python to
Force the stdout and stderr streams to be unbuffered.