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From: Juan Carlos Guzman (juan.guzman_at_[hidden])
Date: 2007-07-30 01:47:04


Hi,

Does anyone know the maximum buffer size I can use in MPI_Send()
(MPI_Recv) function?. I was doing some testing using two nodes on my
cluster to measure the point-to-point MPI message rate depending on
size. The test program exchanges MPI_FLOAT datatypes between two
nodes. I was able to send up to 4 GB of data (500 Mega MPI_FLOATs)
before the process crashed with a segmentation fault message.

Is the maximum size of the message limited by the sizeof(int) * sizeof
(MPI data type) used in the MPI_Send()/MPI_Recv() functions?

My cluster has openmpi 1.2.3 installed. Each node has 2 x dual core
AMD Opteron and 12 GB RAM.

Thanks in advance.
   Juan-Carlos.