How to Check CPU Utilization (sar -u)

1. Use the sar -u command to display CPU utilization statistics.

   $ 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 the sar -u command. At any given moment, the processor is either busy or idle. When busy, the processor is in either user mode or system mode. When idle, the processor is either waiting for I/O completion or “sitting still” with no work to do.

   The following list describes output from the -u option.

   %usr

   Lists the percentage of time that the processor is in user mode

   %sys

   Lists the percentage of time that the processor is in system mode

   %wio

   Lists the percentage of time that the processor is idle and waiting for I/O completion

   %idle

   Lists the percentage of time that the processor is idle and not waiting for I/O

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

Example 13–14 Checking CPU Utilization (sar -u)

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

$ sar -u

SunOS balmyday 5.10 s10_51 sun4u    03/18/2004

00:00:04    %usr    %sys    %wio   %idle
01:00:00       0       0       0     100
02:00:01       0       0       0     100
03:00:00       0       0       0     100
04:00:00       0       0       0     100
05:00:00       0       0       0     100
06:00:00       0       0       0     100
07:00:00       0       0       0     100
08:00:00       0       0       0     100
08:20:00       0       0       0      99
08:40:01       0       0       0      99
09:00:00       0       0       0      99
09:20:00       0       0       0      99
09:40:00       4       1       0      95
10:00:00       4       2       0      94
10:20:00       1       1       0      98
10:40:00      18       3       0      79
11:00:00      25       3       0      72

Average        2       0       0      98