how many kernels running parallel in Mathematica?

Question

Wolfram site states that typically only 4 cores are used with its Parallel feature. If you want more than 4 you need to contact them and pay up.

I have a machine with 2 quad-core hyperthreaded processors. When I run Parallel commands, it starts up 16 kernels 2 x 4 x 2 (factor of 2 for HT, I guess). So it looks like 16 kernels are used and not 4. Correct? It may be the case that my university's license allows for > 4 cores. I just wanted to check to see if I am actually using all available cores.

Thanks.

Answer 1

A standard Mathematica license will have 2 kernels and then 4 sub-kernels for each of the kernels. So that would be 8 if your program used more than 1 normal kernel. Subkernels are essentially what you use for parallel processing.

If you wanted to see how many subkernels you were allowed, please either

(1) Contact Wolfram customer support about this at [email protected]

(2) Check your user portal account at user.wolfram.com. After entering in your password, go to "My Products and Services" and select the copy of Mathematica you are interesting in looking at. In that products page, you will see an entry called "Processes" which will tell you how many different processes your license gives you.

You can use commands such as $KernelCount to see how many subkernels are running.