Implementation and analysis of nonblocking collective operations on SCI networks

Nonblocking collective communication operations are currently being considered for inclusion into the MPI standard and are an area of active research. The benefits of such operations are documented by several recent publications, but so far, research concentrates on InfiniBand clusters. This paper describes an implementation of nonblocking collectives for clusters with the Scalable Coherent Interface (SCI) interconnect. We use synthetic and application kernel benchmarks to show that with nonblocking functions for collective communication performance enhancements can be achieved on SCI systems. Our results indicate that for the implementation of these nonblocking collectives data transfer methods other than those usually used for the blocking version should be considered to realize such improvements.