Performance on hpux 11.0

[vaman]

Some times cpu touching 100% utilisation
Also users facing slow performance in some applications. system is having 4 cpus.
Glance shows issues only in CPU.
In glance it's showing some times cpu goes near 100%.
In CPU graph I/o Rate in some processes is around 70,80.
What could be the performance issue

[Patrick Wallek]

What processes are the top CPU users? What is you memory utilization like? (swapinfo -tam would be helpful) What is disk utilization like? Perhaps you have some disk hotspots and lots of waiting on I/O?

[Sridhar Bhaskarla]

Hi Vaman,

If you see majority of the CPU is consumed by "U" (user processes), then it's most likely either badly written code or the capacity of the system is reached. If you see System CPU, then it can still be user processes working under system mode and it could be a configuration issue. If you see a lot of context switching, then look at the kernel parameter "timeslice" and make sure it is not set to anything other than 10. In anycase, post your 'sar 2 20' output when you it is reaching 100%. Also in glance it will show you the top process. Post it also.


-Sri

[Steven E. Protter]

100% utilization of a CPU is not a problem in and of itsself. A Unix system can happily run at that utilization without any impact at al on users.

What you want to look at is the potential user impact. Is response time slow, are users complaining.

If this is the case, collect some data with the scripts I'm attaching. Use it to identify the resource hogs and deal with the bad applications.

Note also, that if there is not a lot of io/wait on the system, the numbers you are reporting are also not a problem. If disk performance is an issue, you may need to study your raid configuration and lay things out differently.

Oracle and other database vendors recommend data that changes a lot be on raid 1 or raid 10 storage.

SEP