Understanding the CPU utilization

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The five different types of CPU loads used in the CPU utilization reports are described below.

The CPU utilization reports show five different types of CPU load. These types are defined in Table 1, which comes from the sar main page.

Table 1. CPU utilization types
%idle Percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.
%iowait Percentage of time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request.
%system Percentage of CPU utilization that occurred while executing at the system level (kernel).
%nice Percentage of CPU utilization that occurred while executing at the user level with nice priority.
%user Percentage of CPU utilization that occurred while executing at the user level (application).