Re: CPU not used when multi-threaded

Although Oracle sets CPU_COUNT based on the number of CPUs it finds and then uses that to determine some dependent parameters [eg LOG_SIMULTANEOUS_COPIES], it does not physically tie itself to the number of CPUs. Thus, you could always change CPU_COUNT {now _cpu_count ??} and LOG_SIMULTANEOUS_COPIES in earlier releases.
AFAIK, there is nothing in the Oracle code or instance parameters to limit itself to a certain number of CPUs.

On Unix, Oracle actually runs multi-processes. It is for the OS Scheduler to assign processes to different CPUs {although you can use OS commands to specify CPU-affinity}.

Hemant

At 05:39 PM Wednesday, The Human Fly wrote:
>List,
>
>For one of our business critical database, we have assigned 12 cpus
>with multi-thread(logical) of 24 cpus. What we have noticed that
>oracle is not using all the CPU avaibale, at least 4 (8 logical) cpus
>are not being utilized. We have checked from OS level using sar report
>to confirm the sam during business peak hours.
>Is there any limitation with oracle not to use many logical CPUs?
>

Hemant K Chitale
http://web.singnet.com.sg/~hkchital

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