To see how Linux CPU utilization, one command is enough.
The top command monitors CPU utilization, process statistics, and memory utilization. The top section contains information related to overall system status – uptime, load average, process counts, CPU status, and utilization statistics for both memory and swap space.
I use a Centos OS, no swap space now.
To quit from the real time screen, press button q.
If you find a process is always have many memory or running so long, you can kill it to free resource.