My objective is I want to calculate the time perform by MPI_Send &
MPI_Recv . In case MPI_Send, i can put the timer before the MPI_Send and
after its. like this "
tsend= t2 -t1; it mean when the message go to the system buffer, the
control return to the sending process. So I can measure the MPI_Send.
But my problem in MPI_Recv. If i do like MPI_Send( put the timer before
and after MPI_Recv) I think it wrong. Because we dont know exactly when the
message reach the system buffer in receiving side.
So how can we measure the MPI_Recv operation time( time when the
message is copied from the system buffer to the receive buffer) ?