[mvapich-discuss] 64-bit sized messages?

[Chavarria, Daniel G]

Hi MVAPICH developers,

I have a problem where I would like to send and receive messages of MPI_BYTE type where each message is more than 2GB in size.

This is for a big data type problem where I'm initializing the in-memory data containers.  Our local machine here has 64GB per node so 2GB is only a fairly small fraction of the node memory, particularly in the context of a multithreaded run with a single process per node.

Consulting with our local MPI experts they have suggested to send the message in multiple chunks or to use a derived datatype where each element is "large".  I'll likely take one of these routes, however it would be nice to have an interface where I could execute a MPI_Irecv(void *buf, int64_t count, …).

Is this something that you guys have thought about?  Does it come up in the community?

Thanks in advance for your time and attention.

Greetings,

____________________________

Daniel G. Chavarría
Research Scientist
HIGH PERFORMANCE COMPUTING

Pacific Northwest National Laboratory
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daniel.chavarria at pnnl.gov<applewebdata://2EBC18AC-C046-4FAF-954A-01ED68CF1E45/daniel.chavarria@pnnl.gov>
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