Why can i not use all my 64 cores?

I have a 64 core PC running Centos 6.7 and keep getting java.lang.outofmemory errors when i am only using far less than the 64 cores i have, for example parpool(32).

Answer 1

[Walter Roberson]

The Java memory is being shared among all the workers in order to transfer data back and forth with the cores. See

http://www.mathworks.com/help/matlab/matlab_external/java-heap-memory-preferences.html

For older versions, see http://www.mathworks.com/matlabcentral/answers/92813-how-do-i-increase-the-heap-space-for-the-java-vm-in-matlab-6-0-r12-and-later-versions

[Ian West]

Thanks Walter, i have solved the problem. The max porcesses for the user was set to 1024. i had to use ulimit -u 139820 and everything worked fine.