MATLAB 2024 default number of threads

Hello,

I have 16 logical threads in my system but matlab rejects to use more than 8. How can I increase the limit. I used to be able to control it in 2022 version, but once I upgraded to 2024 I could not use more than 8.

[Walter Roberson]

Could you confirm that you are using the Parallel Computing toolbox, and that you are talking about BackgroundPool (thread-based) instead of about Parpool (process-based) ?

[Fadhel Alsaffar]

Yes, I'm using Parallel Computing toolbox with thread-based not process-based.

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/matlab/ref/parallel.backgroundpool.html

If you have a license for Parallel Computing Toolbox, NumWorkers is equal to the number of physical cores you have. For example, if you run MATLAB on a machine with four physical cores, the value is 4. You can reduce this value using maxNumCompThreads before first usage of backgroundPool.

So you cannot increase the number of threads beyond the number of physical cores your system has.

[Fadhel Alsaffar]

Thanks for your answer. I have 16 physical cores. I can run process-based parpool with 16 workers but not more than 8 with thread-based.

I tried to use maxNumCompThreads to change it from 8 to 16 or 12 but could not.

Answer 2

[Edric Ellis]

You can change the maximum number of workers to use with a thread pool by modifying the NumWorkers property in the "Cluster Profile Manager". This will allow you to run a thread pool of size 16.