Balancing Performance and Energy Efficiency of ONoC by Using Adaptive Bandwidth

On-chip optical links can consume considerable energy. Previous work shows that there exists a trade-off between the optical link bandwidth and energy consumption. In this paper, we analyze the temporal behavior of on-chip communication in typical applications and make the following observation: both ONoC and processor cores are not always busy, and there are significant amounts of time during which these components are relatively idle. Base on such an observation, we present a novel technique called Shifting Link to dynamically changing the bandwidth for optical link according to the workload situation. To evaluate our proposed method, we implement the Shifting Link in FlexiShare ONoC architecture. The experiment result shows that, on geometric mean, Shifting Link reduces the energy consumption by 35.0% with only 5.8% decrease in the performance.