Improving the Performance of a Wormhole Router and Wormhole Flow Control

As an emerging and advanced technology, Network-on-Chip (NoC) may become the alternative of the traditional bus-based System-on-Chip (SoC). In an interconnection network structure, interconnected routers are the core of the whole system and the network’s performance mainly depends on their performance. There are many significant factors which determine the working mechanism of a router and its performance, such as topology, switching strategy, routing algorithm, and flow control mechanism. The research topic of this thesis, wormhole flow control, is an excellent flow control mechanism and widely used in interconnection networks. One purpose of this thesis is to enhance the performance of previous wormhole virtual-channel router implementations. The improvement applies to different flit-admission and flit-ejection models. Synthesis results show that the speed of the previous wormhole router is increased from 76 MHz to 200 MHz, and the number of gate counts is reduced by 13.5%. The other purpose of the project is to enhance the performance of wormhole virtual-channel router in general. Traditional wormhole routers arbitrate link usage flit-by-flit. By logically partitioning the flits of packets into groups, we propose a new flow control mechanism which arbitrate link usage group-by-group. This method makes efficient use of buffers, leading to reduced latency and improved network throughput. Its feasibility is validated not only from theoretical analysis, but also from a great deal of simulation results. In addition, synthesis results regarding speed and area show minimal implementation overhead.