Asynchronous MPI messaging on Myrinet

MPI-NP II is a network processor based message manager for MPI. The objectives of MPI-NP II were to reduce host processing and to make use of the processor on the network interface board to do message scheduling and message matching. The design of MPI-NP II is based on microchannels and message rendezvous. MPI-NP II implements MPI nonblocking communication as asynchronous communication and is able to overlap computation with communication. We introduce the concept of k.safe programs to guarantee message delivery based on the available envelope resources independent of the message size. We achieve these benefits without unduly burdening the NIC processor. We obtain a latency of 22 microseconds and a bandwidth of 92 MB/s, which is comparable to other Myrinet MPI implementations that perform MPI message management on the host.