[mpich-discuss] How to change system buffer size for MPI_Send and MPI_Recv?

[Hanjun Kim]

Hi,

I installed mpich2 on a 24-core SMP machine(64bit ubuntu), and
parallelized several programs with MPI. In general, the programs
performed well. However, when large amount of data were sent through
MPI_Send and Recv, the sender became blocked until the receiver
received the data, and its performance became degraded. Is there some
preset system buffer size for MPI_Send and MPI_Recv? If so, how can I
increase the system buffer size? I believe if the system buffer size
of MPI_Send is increased, it will be helpful to get better
performance.

Thank you in advance.

Best,
Hanjun