A Monitored NoC with Runtime Path Adaptation

Networks-on-chip (NoCs) are already a common choice of communication infrastructure for complex systems-on-chip (SoCs) containing a large number of processing resources and with critical communication requirements. A NoC provides several advantages, such as higher scalability, efficient energy management, higher bandwidth and lower average latency, when compared to bus-based systems. Experiments with applications running on NoCs with more than 10% of bandwidth usage show that most of a typical message latency refers to buffered packets waiting to enter the NoC, while the latency portion that depends on packets traversing the NoC is often negligible. This work proposes a Monitored NoC called MoNoC, which is based on a monitoring mechanism and on the exchange of high-priority control packets. Practical experiments show that our fast adaptation method enables transmitting packets with smaller latencies, by using non-congested NoC areas, which reduces the most significant part of message latency.