Investigating Scenario-Conscious Asynchronous Rendezvous over RDMA

In this paper, we propose a light-weight asynchronous message progression mechanism for large message transfers in Message Passing Interface (MPI) Rendezvous protocol that is scenario-conscious and consequently overhead-free in cases where independent message progression naturally happens. Without requiring a dedicated thread, we take advantage of small bursts of CPU to poll for message transfer conditions. The existing application thread is parasitized for the purpose of getting those small bursts of CPU. Our proposed approach is only triggered when the message transfer would otherwise be deferred to the MPI wait call, and it allows for full message progression, achieving 100% overlap. It does not add to the memory footprint of the applications, and is effective in improving the communication performance of most of the applications studied in this paper.