Fault-Tolerant Network-on-Chip Design with Flexible Spare Core Placement

Abstract

Network-on-Chip (NoC) has been proposed as a promising solution to overcome the communication challenges of System-on-Chip (SoC) design in nanoscale technologies. With the advancement in the nanoscale technology, the integration density of Intellectual Property (IP) cores in a single chip have increased, leading to heat dissipation, which in turn makes the system unreliable. Therefore, efficient fault-tolerant methods are necessary at different levels to improve overall system performance and make the system to operate normally. This article presents a flexible spare core placement technique for mesh-based NoC by taking several benchmark applications into consideration. An Integer Linear Programming (ILP)-based solution has been proposed for the spare core placement problem. Also, Particle Swarm Optimisation (PSO)-based meta-heuristic has been proposed for the same. Experiments have been performed by taking several application benchmarks reported in the literature and the applications generated using the TGFF tool. Comparisons have been carried out using our approach and the approach followed in the literature (i) by varying the network size with fixed fault percentage in the network, and (ii) by fixing the network size while varying the percentage of faults in the network. We have also compared the overall communication cost and CPU runtime between ILP and PSO approaches. The results show significant reductions in the overall communication cost, average network latency, and network power consumption across all the cases using our approach over the approaches reported in the literature.