Implementation and Evaluation of a Congestion Aware Routing Algorithm for Networks-on-Chip

The major part of the state of art routing proposals have a limited view of the NoC congestion, since each router takes decisions based on few neighbors' status. Such local decision may lead packets to other congested regions, therefore being inefficient. The goal of this work is to propose and evaluate an adaptive source routing algorithm, where the path between source and target PEs may be modified due to congestion events. The proposed method requires QoS session establishment and traffic monitoring. A QoS session establishes a connection between two IPs, applying application constraints. Traffic monitoring carries congestion information to the target, leading to a global view of the routing path. Evaluated performance figures include latency, traffic distribution and the delay to switch to a new path. For hot-spot traffic scenarios, the average latency is reduced by 10%. The proposed routing method also achieved a better network occupation.