Coarse and fine-grained monitoring and reconfiguration for energy-efficient NoCs

Comparative evaluations of centralized, clustered and distributed architectures, for energy management in NoCs, are presented. The paper starts with the systematic examination of the monitoring, decision-making, and reconfiguration processes in building coarse and fine-grained self-adaptation architectures. With examining the physical support in modern technology, network-wide, cluster-wide and per-node energy-management architectures on NoCs are presented, utilizing either voltage regulators or multiple on-chip power delivery networks (MPNs). To identify the effectiveness and efficiency of energy-performance tradeoffs, extensive quantitative simulations are performed with various temporal and spatially changing traffics. Based on the results, we can first observe that the centralized architecture can not adapt to the traffic´s spatial locality for effective energy-performance tradeoff. Second, the distributed energy management has the lowest energy-delay product mostly attributed to the fast voltage switching of MPNs, while the synchronization incurs noticeable energy overhead. The clustered architecture, last but not least, is a suitable alternative when the advanced MPN technology is not available. It has low energy and energy-delay product, with very small energy overhead from the monitoring communication.