Fully adaptive routing algorithms and region-based approaches for two-dimensional and three-dimensional networks-on-chip

Network congestion has negative impact on the performance of networks-on-chip (NoC). In traditional congestion-aware techniques, congestion is measured at a router level and delivered to other routers, either local or non-local. One of the contributions of this study is to show that performance can be improved if the congestion level is measured for a group of routers, called cluster, and propagated over the network, rather than considering the congestion level of a single router. The presented approach is discussed in both two-dimensional (2D) and three-dimensional (3D) mesh networks. To collect and propagate the congestion information of different clusters, a distributed approach is presented. The gathered information is utilised at routing units to deliver packets through the less congested regions. To distribute packets over the network without forming deadlock, routing algorithms should be carefully designed. The authors take advantage of fully adaptive routing algorithms, providing the maximum degree of adaptiveness for distributing packets. For 2D NoCs, a conventional fully adaptive routing algorithm, named dynamic XY (DyXY), is utilised. However, for 3D NoCs a fully adaptive routing algorithm is proposed and this method is called 3D-FAR. On top of each fully adaptive routing algorithm, a region-based approach is developed.