Local Traffic-Based Energy-Efficient Hybrid Switching for On-Chip Networks

Abstract

Advanced flow control mechanisms employed by modern on-chip networks are the reasons of large energy footprint and long per-hop latency. On the other hand, dated and simpler flow controls such as circuit switching can draw far less power and offer an end-to-end latency analogous to wire delay. In this paper, we present a hybrid flow control mechanism, which mixes both virtual channels and circuit-switching, to provide a latency-competitive and energy-efficient on-chip network design. Contrary to existing hybrid switching designs, our proposal is based on local traffic so that circuits are formed without the knowledge of end-to-end traffic. When compared to on-chip networks with virtual channels, our proposal achieves a very competitive latency per flit, for up to 4% lower, while also dramatically suppressing the energy per flit by up to 18%.