HyCo: A Low-Latency Hybrid Control Plane for Optical Interconnection Networks

Next-generation multiprocessor systems point to the integration of a large number of cores (e.g., processing and memory) where electrical networks-on-chip (eNoCs) can improve the communication performance. As the number of integrated cores increases, metallic interconnect in eNoCs becomes a bottleneck, leading to communication performance degradation and increased power consumption. Optical interconnection networks (OINs) have emerged to outperform the communication infrastructure in multiprocessor systems. Nevertheless, OINs’ full capability is curbed by high latency electrical controllers required to orchestrate and (re)configure the underlying photonic components, realizing a path between sending and receiving cores. Control techniques impose a high latency to perform the network routing, limiting the full utilization of OINs. In this paper, we design a novel low-latency Hybrid Controller (HyCo) that employs acceleration techniques to reduce its execution time. HyCo is developed based on integrating centralized and distributed control techniques as well as by using pre-calculated network routes and a Bloom filter, all of which result in a considerable reduction in HyCo’s latency. Simulation and prototyping results for networks up to 64×64 indicate a latency smaller than 50 ns, in the worst-case scenario.