[OMPI users] Maximum message size for MPI_Send()/MPI_Recv() functions

[Juan Carlos Guzman]

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.