All-to-all broadcast on switch-based clusters of workstations

This paper presents efficient all-to-all broadcast algorithms for arbitrary irregular networks with switch-based wormhole interconnection and unicast message passing. First, all-to-all broadcast is considered within a single switch cluster. Both combining and non-combining algorithms are compared via analytical modeling and simulation. The characteristics of optimal all-to-all broadcast operation are considered and applied to the development of multiswitch algorithms. The single switch algorithms are considered on two switch clusters and a near-optimal algorithm is developed which schedules use of interconnecting links where the potential for link contention exists. Finally, the link scheduling concept is extended to handle arbitrary irregular networks. Operation of this algorithm is simulated on a 128-node irregular network, and shows a 27.1% improvement in performance compared to other algorithms.