How to Check CPU Utilization ( `sar -u`)

Display CPU utilization with the sar -u command.

$ sar -u
00:00:00 %usr %sys %wio %idle
01:00:00 0 0 0 100

(The sar command without any options is equivalent to sar -u.) At any given moment, the processor is either busy or idle. When busy, the processor is in either user or system mode. When idle, the processor is either waiting for I/O completion or "sitting still" with no work to do.

Output from the -u option is described in the table below.

Table 36-17 Output From the sar -u Command


Field Name	Description
`%sys`	Lists the percentage of time that the processor is in system mode
`%user`	Lists the percentage of time that the processor is in user mode
`%wio`	Lists the percentage of time the processor is idle and waiting for I/O completion
`%idle`	Lists the percentage of time the processor is idle and is not waiting for I/O

A high %wio generally means a disk slowdown has occurred.

Example--Checking CPU Utilization

The following example shows output from the sar -u command.

$ sar -u
SunOS venus 5.8 Generic sun4u 09/07/99
00:00:00 %usr %sys %wio %idle
01:00:00 0 0 0 100
02:00:02 0 0 0 100
03:00:00 0 0 0 100
04:00:00 0 0 0 100
05:00:01 0 0 0 100
06:00:00 0 0 0 100
07:00:00 0 0 0 100
08:00:01 0 0 0 100
08:20:00 0 0 0 100
08:40:00 0 0 0 100
09:00:00 0 0 0 100
09:20:00 0 0 0 100
09:40:00 0 0 0 100
10:00:00 0 0 0 100
10:20:00 0 0 0 100
10:40:01 0 0 0 100
11:00:00 5 2 10 82
Average 0 0 0 100