Low-cost fault-tolerant routing for regular topology NoCs

This paper presents a novel low-cost routing algorithm for regular (mesh) topology networks-on-chip. While deterministic NoC routing algorithms such as XY routing are still widely used, they can fail when a link or router in the NoC fails temporarily or permanently, because they provide no adaptivity. However, switching to a topology-agnostic routing algorithm can be a very costly approach in terms of performance and/or area. Instead, we propose switching the dimension order to YX instead of XY routing and back accordingly. Preliminary experimental results show that this approach maintains the simplicity of dimension-order routing and, therefore, its hardware efficiency, while greatly improving reachability. This approach can be combined with topology-agnostic approaches to reduce packet loss during algorithm reconfiguration time.