CPU States

This line indicates the amount of time the CPU spent in each of several states, displayed as percentages. The numbers reflect the percentage of the time since the last screen update that the CPu spent in each state. The output for this line requires past history, and it is not shown on the first display that top produces.

The first four states in the list below are found on most every Unix system. Other state names may appear on different platforms, and some of these are also listed below.

Idle Nothing to do
User Running a user's process
Kernel Handling a kernel call, fault, or interrupt
Nice Running a user's niced process
Wait Waiting on some form of i/o
iowait Waiting on user i/o
Swap Waiting on swapping or paging i/o