[OMPI users] computing the latency with OpenMpi

2010-09-13 Thread Georges Markomanolis
Dear all, I have some questions about the duration of the communication with MPI_Send and MPI_Recv. I am using either SkaMPI either my implementation to measure the pingpong (MPI_Send and MPI_Recv) time between two nodes for 1 byte and more. The timing of the pingpong is 106.8 microseconds. A

[OMPI users] latency #2

2010-09-13 Thread Georges Markomanolis
Dear all, Hi again, after using MPI_Ssend seems to be what I was looking for but I would like to know more about MPI_Send. For example sending 1 byte with MPI_Send it takes 8.69 microsec but with MPI_Ssend it takes 152.9 microsec. I understand the difference but it seems that from one messag