How is CPU usage calculated?

Question

On my desktop, I have a little widget that tells me my current CPU usage. It also shows the usage for each of my two cores.

I always wondered, how does the CPU calc

Answer 1

1. The CPU does not get 'hung' up, it is simply operating at peak capacity, meaning it is processing as many instructions as it is physically capable every second. The process that is calculating CPU usage is some of those instructions. If applications try to do operations faster than the CPU is capable, then simply they will be delayed, hence the 'hung up'.

2. The calculation of CPU utilization is based on the total available utilization. So if a CPU has two cores, and one core has 30% usage, and the other is 60%, the overall utilization is 45%. You can also see the usage of each individual core.