Runtime multi-optimizations for energy efficient on-chip interconnections1

On-chip interconnection (or NoC) is a major performance and power contributor to modern and future multicore processors. So far, many optimization techniques have been developed to improve its bandwidth, latency and power consumption. But it is not clear how energy efficiency is affected since an optimization technique normally comes with overheads. This paper thus attempts to address when and how such optimization techniques should be applied and tuned to help achieve better energy efficiency. We firstly model the performance and energy impacts of representative NoC optimization techniques. These models help us more easily understand the consequences when applying these optimization techniques and their combinations under different circumstances. Moreover, based on such modeling, we propose and implement an adaptive control over these NoC optimization techniques to improve both performance and energy efficiency of the network. Our results show that, this proposal can achieve an average improvement of 26% and 57% on network performance and energy delay product, respectively.