[mpich-discuss] The max amount of data each process can send in MPI_Alltoallv

Pavan Balaji balaji at mcs.anl.gov
Sun Dec 15 19:21:11 CST 2013

On Dec 16, 2013, at 9:49 AM, Huiwei Lu <huiweilu at mcs.anl.gov> wrote:
> @JT, yes, if the data continue to grow and there is no proper way to do it in MPI type, I will have to partition the buffer to smaller trunks.

MPI (standard) can send infinitely large data using Rajeev’s suggestion.  The internal MPICH stack can allow up to 64-bits (16 exabytes) because of its internal bookkeeping.  When people start sending more than 16 exabytes in a single message, we’ll fix that.  :-)

Pavan Balaji

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