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Determine Total CPU Utilization

MikeL_4
Super Advisor

Determine Total CPU Utilization

 

We are running on HP-UX 11.31 itanium server, and CA's monitor keeps alerting on High CPU usage 95+%

 

However when we go into glance it is showing in the 30% range...

 

 Glance 11.00.044               05:45:53 tmopdb01     ia64                    Current  Avg  High
------------------------------------------------------------------------------------------------
CPU  Util   S  SU              U                                               |                               30%       32%      53%

 

So I guess the question is what command gives a true "Total CPU Percentage"  ???

 

Also noticed in glace that although it is showing at a current 30% usage level, there is a line that also

shows an oracle process at 95% utilization

 

Top CPU user: PID       4452, oracletmop         95.3% cpu util
Active CPUs: 16

 

Do you know why this would show a difference like this ???

2 REPLIES
Patrick Wallek
Honored Contributor

Re: Determine Total CPU Utilization

It is entirely possible that one Oracle process could be using 95% of a single CPU, but overall your TOTAL (meaning ALL 16 CPUs in the system) usage is just 30%.  

 

 

Bill Hassell
Honored Contributor

Re: Determine Total CPU Utilization

You'll have to ask CA what their report means. As is true for any computer, CPU usage is only meaningful when there is exactly one processor installed. With 16 processors, you will need 16 copies of Oracle running at the same time to reach 100% system PU usage. One process running at 100% on your system doesn't affect the other processes at all.

 

The question is: Is there a problem with Oracle? Is it normal for Oracle to use almost 100% CPU? Is the 100% CPU usage lasting for hours or days at a time? You'll have to ask your DBA whether this is normal.

 

CPU usage can be very tricky to report. A multithreaded application can show much more than 100% (like 150% or 200%) since all the threads are normally accumulated with the main program.



Bill Hassell, sysadmin