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Oracle processes staying on one processor

Brent Barton
Occasional Contributor

Oracle processes staying on one processor

We migrated several Oracle instances from a K580 6-way to an N4000 4-way. Ever since the move we have noticed that most (if not all) of the Oracle processes want to run on CPU 0, and will wait for that CPU. Looking at Glance shows:

CPU 0 100% UTIL
CPU 1 2.7% UTIL
CPU 2 0.6% UTIL
CPU 3 1.9% UTIL

I found a post on Dutchworks that the DBA can instruct Oracle to use multiple processors, but I haven't found any evidence on how.
Any Ideas?

Thanks...
6 REPLIES
S.K. Chan
Honored Contributor

Re: Oracle processes staying on one processor

If the same Oracle version is able to run in multi-cpu mode in your K-class it should do the same for the N-class (HP-UX version the same ?).
Anyway we had this situation before on the L-class (11.0) and this 2 patches fixed our problem. Check with HP Response center first.
PHKL_18543 11.00 PM/VM/UFS/async/SCSI/IO/DMAPI/JFS perf patch
PHNE_25385 11.00 Streams PTY cumulative patch
Anthony deRito
Respected Contributor

Re: Oracle processes staying on one processor

Are you using PRM by any chance? The standard HP-UX job scheduler is very complicated and does its best based on loading and priority to maintain load balance between multiple processors. I did not know Oracle has this kind of control. But then again, I don't know much about Oracle. Check if PRM is being used.

Tony
Brent Barton
Occasional Contributor

Re: Oracle processes staying on one processor

PRM is not installed. I am currently working with Response Center to discuss patches, etc. I will reply with their response.

Thanks
Wodisch
Honored Contributor

Re: Oracle processes staying on one processor

Hello Brent,

have you set the "init.ora" parameter "cpu_count" to the number of cpus you want to use for/by Oracle? The default is only one...

HTH,
Wodisch
Sanjay_6
Honored Contributor

Re: Oracle processes staying on one processor

Brent Barton
Occasional Contributor

Re: Oracle processes staying on one processor

We run the security product SeOS by CA. After removing the product the load was then balanced across all 4 processors. I then reinstalled SeOS and the load was still balancing across all cpu's. So my guess is that the initial install of the security product was not clean.