MPI_Reduce algorithm for OpenFlow-enabled network

The MPI reduction operation such as MPI_Reduce and MPI_Allreduce are frequently used and time-consuming operations. The performance enhancement of these operations can substantially speed up large-scale parallel applications. In this paper, a greedy based MPI_Reduce algorithm called Greedy Shortest Binomial Tree (GSBT) is proposed. This proposed algorithm leverages SDN technology and OpenFlow network to speed up MPI reduction operations. This is accomplished using network topology information from the OpenFlow controller to reduce overall hops in message transmission. The implementation of the proposed algorithm by modifying MPI library and OpenFlow controller is presented. The proposed GSBT algorithm has been evaluated in a real test-bed to compare with the traditional approaches used in both MPICH and Open MPI. The result shows that GSBT algorithm is faster than standard algorithms 30.48-66.35% for Open MPI and faster 50.77-82.89% for MPICH when message size between 2 KB - 24 KB.