An Improved Router Design for Reliable On-Chip Networks

Aggressive technology scaling into the deep nanometer regime has made the Network-on-Chip (NoC) in multicore architectures increasingly vulnerable to faults. This has accelerated the need for designing reliable NoCs. To this end, we propose a reliable NoC router architecture capable of tolerating multiple permanent faults. The proposed router achieves a better reliability without incurring too much area and power overhead as compared to the baseline NoC router or other fault-tolerant routers. Reliability analysis using Mean Time to Failure (MTTF) reveals that our proposed router is six times more reliable than the baseline NoC router (without protection). We also compare our proposed router with other existing fault-tolerant routers such as Bullet Proof, Vicis and RoCo using Silicon Protection Factor (SPF) as a metric. SPF analysis shows that our proposed router is more reliable than the mentioned existing fault tolerant routers. Hardware synthesis performed by Cadence Encounter RTL Compiler using commercial 45nm technology library shows that the correction circuitry incurs an area overhead of 31% and power overhead of 30%. Latency analysis on a 64-core mesh based NoC simulated using GEM5 and running SPLASH-2 and PARSEC benchmark application traffic shows that in the presence of multiple faults, our proposed router increases the overall latency by only 10% and 13% respectively while providing better reliability.