hide cpu cores from an application

thllgo · 06-16-2010, 10:33 AM

Is it possible to hide cpu cores from an application?

I am running RHEL 5.5 on a Sun 4450 with 24 cores. We use Sybase database. Licensing for Sybase is by core. I would like to restrict Sybase to using 8 of the 24 cores and allow other apps on the system to use the rest of the cores. I want to reserve 8 cores for Sybase use only and Sybase only has access to those 8 cores.

Am I dreaming?
Thank you for any help.

thllgo · 06-16-2010, 10:40 AM

Note: I don't think limits.conf will work as it limits cpu time. I want to limit the number of cpus Sybase sees.

edenCC · 06-17-2010, 03:42 AM

I'd say it should be possible.
It would be better to disable other cores and leave only 8 cores.

I ever did similar things on Dell r410/r710 servers, turned off some unwanted cores with the help of OMSA, but not sure whether it's supported by Sun 4450.

As Sun Fire X4450 has 4 CPUs, you probably need to make sure whether they are hyper-threaded or just physical core.

syg00 · 06-17-2010, 04:08 AM

Check out cgroups.