operating-system User Space and Kernel Space Exam CPU time allocation between user space and kernel space

Example

Use top command to exam CPU time allocation between user space and kernel space.

Explanation:

1. 24.8 us (user space): 24.8% of CPU time is spent on user process.
2. 0.5 sy (system): 0.5% of CPU time is spent on kernel space.
3. ni (niceness): the ratio of CPU time spent on low priority processes.
4. id (idle): the ratio of CPU time spent on idle processes (during the period of time, CPU can not do anything).
5. wa (wait): the ratio of CPU time spent on waiting for I/O (during the period of time, CPU can not do anything).
6. hi (hardware interrupt): the ratio of CPU time spent on responding hardware interruption.
7. si (software interrupt): the ratio of CPU time spent on responding software interruption.
8. st (stole time): the ratio of CPU time stolen by virtual machine.