Inconsistent CPU Usage from sar & top

[Richard Riley]

I have encountered the same thing on a couple of my machines.  I found
that if I run "sar -P ALL" it shows utilization per CPU with realistic
utilization numbers.  This seems to only happen on some new Dell
machines.  Have yet to figure out why.  Hopefully someone will have an
answer for both of us.

Richard

> -----Original Message-----
> From: redhat-sysadmin-list-bounces at redhat.com [mailto:redhat-
> sysadmin-list-bounces at redhat.com] On Behalf Of Claude Lindo
> Sent: Tuesday, June 19, 2007 2:21 PM
> To: redhat-sysadmin-list at redhat.com
> Subject: Inconsistent CPU Usage from sar & top
> 
> Hi,
> 
> I use both sar and top to monitor system resource utilization my
> RHEL 4
> servers, but I notice that they report different CPU statistics for
> the
> same time period, e.g:
> > sar 1 5
> 17:00:01 CPU %user %nice %system %iowait %idle
> 17:00:02 all 20.00 0.00   5.00   75.00  0.00
> 17:00:03 all 22.00 0.00   6.00   72.00  0.00
> 17:00:04 all 15.00 0.00   9.00   76.00  0.00
> 17:00:05 all 13.00 0.00   5.00   82.00  0.00
> 17:00:06 all  7.00 0.00   3.00   90.00  0.00
> Average: all 15.40 0.00   5.60   79.00  0.00
> 
> > top
> top - 17:00:07 up 13 days, 9:56, 22 users, load average: 0.95, 0.88,
> 0.91
> Tasks: 176 total, 2 running, 173 sleeping, 0 stopped, 1 zombie
> Cpu(s): 8.1% us, 11.8% sy, 0.0% ni, 75.5% id, 4.4% wa, 0.1% hi, 0.1%
> si
> 
> PID    USER   PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 3267  informix 17 0 3052 1176 748 S 11.1 0.2 6:46.73 top
> 14729 root     16 0 2736 896  660 R  3.7 0.2 0:00.05 top
> 2656 informix  15 0 213m 166m 165m R 1.9 33.0 535:39.68 oninit
> 2660 root 15 0 213m 141m 141m S 1.9 28.1 43:36.36 oninit
> 1 root 16 0 1788 516 460 S 0.0 0.1 0:05.61 init
> 2 root 34 19 0 0 0 S 0.0 0.0 0:00.18 ksoftirqd/0
> 3 root 5 -10 0 0 0 S 0.0 0.0 0:00.11 events/0
> 
> This happens on several servers and across time periods. The two
> utils
> report different CPU usage stats; which one is correct or is it that
> I
> am using them incorrectly?
> 
> Claude.
> 
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