AIX : Use sar to check cpu usage

stephane

If you’re looking for CPU usage statistics and system performance on IBM AIX, sar might just be the tool your looking for. It’ll display information for 5 minutes intervals from midnight to current time. The output looks like this :

login@servername:/> sar

AIX servername 3 5 00CFE81B4C00    01/25/10

Configuration du système : lcpu=20 ent=8,00

00:00:01    %usr    %sys    %wio   %idle   physc   %entc
00:05:01       2       2       0      96    0,40     5,0
00:10:01       3       2       0      94    0,48     6,0
00:15:00       1       1       0      98    0,21     2,6
00:20:01       1       1       0      98    0,23     2,9
00:25:01       2       1       1      97    0,25     3,2
00:30:01       1       1       0      98    0,23     2,9
00:35:00       2       1       1      96    0,31     3,8
00:40:01       1       1       0      98    0,21     2,6
00:45:01       1       1       0      98    0,22     2,7
00:50:00       1       1       0      98    0,23     2,8
00:55:00       1       1       0      98    0,21     2,6
01:00:00       1       1       0      98    0,21     2,6
01:05:00       2       1       0      96    0,35     4,4

The columns are the usual for this type of tools :

  1. %usr : the percent of time spent in user land. The higher the more CPU intensive processes you are running.
  2. %sys : the percent of time spent in kernel. This is mostly due to I/O intensive processes and/or processes performing a lot of syscalls.
  3. %wio : I’ve got no idea about that one … If you’ve got an explanation for this, feel free to hit the comments. I suspect this is the time spent waiting for I/Os to complete, or waiting after a busy device. This could be a sign of I/O (disk, network) bottlenecks
  4. %idle : the percent of time spent doing … nothing. The higher this number, the more underused your machine
  5. physc : no idea neither !
  6. %entc : the number of CPU used to absorb the load

If you’re looking for a top like tool, topas is the standard AIX equivalent.