Fault-Tolerant Irregular Topology Design Method for Network-on-Chips

As the technology sizes of integrated circuits (ICs) scale down rapidly, current transistor densities on chips dramatically increase. While nanometer feature sizes allow denser chip designs in each technology generation, fabricated ICs become more susceptible to wear-outs, causing operation failure. Even a single link failure within an on-chip fabric can halt communication between application blocks, which makes the entire chip useless. In this study, we aim to make faulty chips designed with Network-on-Chip (NoC) communication usable. Specifically, we present a fault-tolerant irregular topology generation method for application specific NoC designs. Designed NoC topology allows a different routing path if there is a link failure on the default routing. We compare fault-tolerant topologies with regular fault-tolerant ring topologies, and non-fault-tolerant application specific irregular topologies on energy consumption, performance, and area using multimedia benchmarks and custom-generated graphs.