Aside from checking the kernel log (sudo dmesg) and system log (sudo journalctl -xe) for any interesting messages, I might suggest simply watching for any processes which are abnormally high while the system is running slow. My initial approach would be to use htop (disable “Hide Kernel Threads” and enable “Detailed CPU Time”), and seeing which processes, if any, are eating up your CPU time. The colored core utilization bars at the top show how much CPU time is being spent on what: gray for disk wait, red for kernel, green for regular user process, etc. That information will be a good starting point.
Aside from checking the kernel log (
sudo dmesg) and system log (sudo journalctl -xe) for any interesting messages, I might suggest simply watching for any processes which are abnormally high while the system is running slow. My initial approach would be to usehtop(disable “Hide Kernel Threads” and enable “Detailed CPU Time”), and seeing which processes, if any, are eating up your CPU time. The colored core utilization bars at the top show how much CPU time is being spent on what: gray for disk wait, red for kernel, green for regular user process, etc. That information will be a good starting point.