Best of both worlds: A bus enhanced NoC (BENoC)

While NoCs are efficient in delivering high throughput point-to-point traffic, their multi-hop operation is too slow for latency sensitive signals. In addition, NoCS are inefficient for multicast operations. Consequently, although NoCs outperform busses in terms of scalability, they may not facilitate all the needs of future SoCs. In this paper, the benefit of adding a global, low latency, low power shared bus as an integral part of the NoC architecture is explored. The Bus-enhanced NoC (BENoC) is equipped with a specialized bus that has low and predictable latency and performs broadcast and multicast. We introduce and analyze MetaBus, a custom bus optimized for such low-latency low power and multicast operations. We demonstrate its potential benefits using an analytical comparison of latency and energy consumption of a BENoC based on MetaBus versus a standard NoC. Then, simulation is used to evaluate BENoC in a dynamic non-uniform cache access (DNUCA) multiprocessor system.