Hi,

In my program I have a loop of this form:

loop {
  MPI_Send(small message)
  MPI_Isend(big message)
}
do_some_computation()
MPI_Waitall

The sends and isends all have the same target rank.

Is there a risk that an MPI_Send forces a previously posted MPI_Isend to complete before it can complete itself (in which case I would loose the benefit of using non-blocking sends)?

Thanks,

Matthieu