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System Administration Guide

How to Check CPU Utilization (sar)

Display CPU utilization with the sar -u command. 


$ sar -u
SunOS venus 5.6 Generic sun4m    08/20/96
00:00:03    %usr    %sys    %wio %idle
01:00:02       0       1       0    99

(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 Table 64-17.

Table 64-17 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 5.6 Generic sun4m    08/20/96
14:28:12    %usr    %sys    %wio   %idle
14:29:12      22      27      18      32
14:30:12       6      24      13      57
14:31:12       8      28      19      45
 
Average       12      27      17      45