how to ask for a pool size when using parpool with threads
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Dear all,
using R2020b, looks like the flag "threads" when using a parpool excludes providing a pool size... is there a reason for that? How can provide an explicite number of workers?
thanks,
Daniel
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Accepted Answer
Raymond Norris
on 19 Nov 2020
Edited: Raymond Norris
on 19 Nov 2020
There isn't from within parpool. When you create a Threads pool, the size of the pool is identical to maxNumCompThreads, which by default is the number of physical cores on the machine.
One workaround is as follows. Assume you have 4 cores and you want a thread pool of 2.
old_thread_count = maxNumCompThreads(2);
p = parpool("threads");
Keep in mind, adjusting maxNumCompThreads could have an impact on other MATLAB functions (though perhaps not since you're now running a pool), so I'd suggest setting it back once you're done with the pool.
p.delete
maxNumCompThreads(old_thread_count);
Is there a particular reason you want to adjust the size?
4 Comments
Rick Amos
on 2 Oct 2023
As an update to Raymond's answer, we added this capability to thread-based pools in R2022b. For R2022b or later, you can control thread-based pool size directly via parpool:
parpool("threads", 2);
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