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Hi sys cpu utilization

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Regular Advisor

Hi sys cpu utilization

Hi All,

On two of my boxes System CPU utilization is about 80% and User CPU utilization is about 20%.
Is that mean that I have CPU bottleneck?

Honored Contributor

Re: Hi sys cpu utilization

Hi ,

Sys CPU utilization should not be that high . Typically it is the other way round . User is high and Sys is low.

Run top on you machine and find out which processes are taking high CPU .

Keep it simple
Regular Advisor

Re: Hi sys cpu utilization

Hi Vikas,

These are K460 servers with 4 CPU and I am running SYBASE.
On the "top" are "dataserver"s and BMC Patrol Agent.
Honored Contributor

Re: Hi sys cpu utilization

Typically, when your system CPU utilization numbers are that high, it means that you are suffering from some sort of disk i/o bottleneck.

If you have glance, use it to get a better idea of where your bottlenecks are, otherwise use sar and vmstat.
Remember, wherever you go, there you are...
Regular Advisor

Re: Hi sys cpu utilization

Hi Jim,

Can you give me some directions what exactly to look at the output of "sar" and "vmstat".
Respected Contributor

Re: Hi sys cpu utilization

Hi Troyan,

Like what Jim said, your system may be suffering from heavy disk I/O as the kernel was getting very busy on moving disk blocks. To have a deeper look at the problem, run glance (hope you have it), call up the system call report screen then you'll see which is the most busy system call in your systems, you may see the "read" and "write" calls are among the top of the list. Almost you should check out if these disk I/Os are being spreaded evenly among the disks (eg. use sar -d 3 99).

The other system call that you should pay attention to is "select". If the system spend large amount of cpu time on it then check out the Sybase configure parameter "runnable process search count", and see if it was being set to a very high value.

Regular Advisor

Re: Hi sys cpu utilization

The sys cpu usage should not be so high.
Also check up if this situation is consistent or happens only when you try to do some "extra" stuff on the box.
To use glance is also a good idea.
you can try thes commands to have a quick idea of what is happening.
2:33pm up 2 days, 18:42, 24 users, load average: 0.03, 0.07, 0.06

Here the load average of anything above 1.5 to 2 means the processes are waiting for the CPU.
#vmstat -n
This will give u some idea about page ins and outs .There should not be any page ins or outs.
#sar -d 5 20
will tell u if there is lot of io happening.

Its ALL in the MATRIX