BIXBAR: A low cost solution to support dynamic link reconfiguration in networks on chip

Abstract

Improving link utilization is a key aspect in interconnection network design. Reconfigurable-direction interrouter links optimize network resource utilization, which substantially increases the maximum achievable throughput. In the case of On-chip Networks, the short distance between adjacent routers makes feasible fast link arbitration, which makes dynamic link reconfiguration an attractive solution. In this paper we propose a low-cost router micro-architecture that is able to deal with reconfigurable links with a marginal cost over a conventional router. The key element of the proposal is a bidirectional crossbar, which enables reconfiguration of links, without significantly increasing router area and energy. The results obtained indicate that with this proposal, system performance could be improved, for some selected workloads, by up to 25% while energy-performance tradeoff is reduced by 20%, avoiding the additional costs entailed in other state-of-the-art routers capable of performing dynamic link reconfiguration.