[OMPI users] Performance of MPI_Isend() worse than MPI_Send() and even MPI_Ssend()

[Jeremias Spiegel]

Hi,
I'm working with Open-Mpi on an infiniband-cluster and have some strange 
effect when using MPI_Isend(). To my understanding this should always be 
quicker than MPI_Send() and MPI_Ssend(), yet in my program both MPI_Send() 
and MPI_Ssend() reproducably perform quicker than SSend(). Is there something 
obvious I'm missing?

Regards,
Jeremias