Achieving balanced buffer utilization with a proper co-design of flow control and routing algorithm

Buffer resource minimization plays an important role to achieve power-efficient NoC designs. At the same time, advanced switching mechanisms like virtual cut-through (VCT) are appealing due to their inherited benefits (less network contention, higher throughput, and simpler broadcast implementations). Moreover, adaptive routing algorithms exploit the inherited bandwidth of the network providing higher throughput. In this paper, we propose a novel flow control mechanism, referred to as type-based flow control (TBFC), and a new adaptive routing algorithm for NoCs. First, the reduced flow control strategy allows using minimum buffer resources, while still allowing VCT. Then, on top of TBFC we implement the safe/unsafe routing algorithm (SUR). This algorithm allows higher performance than previous proposals as it achieves a proper balanced utilization of input port buffers. Results show the same performance of fully adaptive routing algorithms but using less resources. When resources are matched, SUR achieves up to 20% throughput improvement.