Towards graceful aging degradation in NoCs through an adaptive routing algorithm

Continuous technology scaling has made aging mechanisms such as Negative Bias Temperature Instability (NBTI) and electromigration primary concerns in Network-on-Chip (NoC) designs. In this paper, we model the effects of these aging mechanisms on NoC components such as routers and links using a novel reliability metric called Traffic Threshold per Epoch (TTpE). We observe a critical need of a robust aging-aware routing algorithm that not only reduces power-performance overheads caused due to aging degradation but also minimizes the stress experienced by heavily utilized routers and links. To solve this problem, we propose an aging-aware adaptive routing algorithm and a router microarchitecture that routes the packets along the paths which are both least congested and experience minimum aging stress. After an extensive experimental analysis using real workloads, we observe a 13%, 12.7% average overhead reduction in network latency and Energy-Delay-Product-Per-Flit (EDPPF) and a 10.4% improvement in performance using our aging-aware routing algorithm.