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Allocate the memory of an entire node on a single MPI process

Vasileios_K_
Beginner
136 Views

Dear all,

I want to benchmark an implementation in cluster architectures. The number of processes need not be high, however I need as much memory as possible on each MPI process. For example, I have access to a large cluster where each node has two sockets and each socket has 6 multithreaded cores. Assume that I launch one MPI process per node (or per socket). Can I make this particular MPI process to access the entire node's (socket's) memory? Right now I can launch a single MPI process per socket but the amount of memory that the process sees is only the that of a single core.

Thank you!

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Heinrich_B_Intel
Employee
136 Views

Hi Vasileios,

I wonder why you get the strange behavior with MPI on your nodes. A single MPI process should be able to access the whole memory unless you did restrict it by using numactl. Do you have a reproducer for this behavior? How much memory were you able to allocate? How much memory was available (shown by e.g. top).

thanks, 
Heinrich

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