PreNoc: Neural Network based Predictive Routing for Network-on-Chip Architectures

In this paper, we introduce a neural network based predictive routing algorithm for on-chip networks which uses anticipated global network state and congestion information to efficiently route network traffic. The core of the algorithm is a multi-layer neural network machine learning approach where the inputs are level of occupancy of virtual channels, average latency for a particular router to be selected for route computation, the probability of virtual channel allocation, and the probability of winning switch arbitration at the crossbar. The algorithm lends itself to both node routing and source routing. To evaluate the PreNoc routing algorithm, we simulate both synthetic traffic and real application traces using a cycle-accurate simulator. In most test cases, the proposed approach outperforms current deterministic and adaptive routing techniques in terms of latency and throughput. The hardware overhead for supporting the new routing algorithm is minimal.