Smart Butterfly: Reducing static power dissipation of network-on-chip with core-state-awareness

摘要

While power gating is a promising technique to reduce the static power consumption of network-on-chip (NoC), its effectiveness is often hindered by the requirement of maintaining network connectivity and the limited knowledge of traffic behaviors. In this paper, we present Smart Butterfly, a core-state-aware NoC power-gating scheme based on flattened butterfly that utilizes the active/sleep state information of processing cores to improve power-gating effectiveness. Smart Butterfly exploits the rich connectivity of the flattened butterfly topology to allow more on-chip routers to be power-gated when their attached cores are asleep. We present two heuristic algorithms to determine the set of routers to be turned on to maintain connectivity and allow tradeoff between power consumption and average packet latency. Simulation results show an average of 42.85% and 60.48% power reduction of Smart Butterfly over prior art on 4×4 and 8×8 networks, respectively.