Energy-Efficient Multiple Network-on-Chip Architecture With Bandwidth Expansion

As technology feature sizes diminish to the nanometer regime, the leakage power crisis has become a major challenge in network-on-chip (NoC) design. Power gating (PG) is used to mitigate growing leakage power as an effective static power-saving technique. Applying PG in a multiple NoC (Multi-NoC) rather than a traditional NoC is a promising solution. However, limited by the channel width of the subnets, the increase in packet length will bring a severe serialization issue and performance loss. Previous Multi-NoC schemes have to wake up more subnets to minimize the performance loss, which also sacrifices their energy efficiency. In this article, we introduce an architecture, namely, BandExp, which allows subnets to expand their bandwidth by utilizing the idle physical links of other subnets. More bandwidth helps subnets mitigate the serialization issue and reduce the performance loss. Meanwhile, other subnets gain longer sleep cycles and thus save more energy. Evaluation results indicate that compared to the state-of-the-art Catnap, the proposed architecture reduces the average packet latency and execution time of different benchmarks by 19.3% and 3.2%, respectively. Also, the net static energy of the network is reduced by 23.2% on average, while the incurred area overhead is only 1.3%.