Making path selection faster: a routing algorithm for ONoC

Optical network-on-chip (ONoC) is an effective communication architecture to realize high performance and energy efficiency. Diverse routing algorithms are proposed to avoid the congestion, tolerate the faults, and reduce the insertion loss or energy consumption. However, existing algorithms did not consider the characteristic optical circuit-switching of ONoC, which aggravates the network congestion and degrades the associated performance severely. In this paper, by exploiting congestion prediction technique, we propose a new routing algorithm for ONoC, named loophole-routing, to improve the success rate of path-setup and decrease the latency. We use the congestion prediction technique to analyze the latency and predict the port condition caused by the network congestion. Theoretical analysis and experimental results of different synthetic traffic patterns show that the loophole-routing improves network latency over XY routing and OE-turn routing by 15.56%, 25.71%, 18.92%, 66.67% and 42.86% under uniform, hotspot1, hotspot2, transpose2 and transpose3 traffic patterns while improving the saturation throughput by 31.43%, 34.33%, 35.29%, 67.86% and 99.5% under uniform, hotspot1, hotspot2, transpose2 and transpose3 traffic patterns on average than XY routing. In addition, our proposed loophole-routing has the benefits of high path diversity and adaptive degree and low computing complexity and overhead and the potential to make fault-tolerant path selection.