PFT — A low overhead predictability enhancement technique for non-preemptive NoCs

Performance predictability in Networks-on-Chip usually comes with high area and energy overheads. As an alternative approach, this paper presents a low overhead technique called Priority Forwarding and Tunnelling (PFT) which aims to enhance performance predictability in simple non-preemptive NoC routers. It addresses the negative impact of Head-of-line (HOL) blocking by temporarily boosting the priority of low priority packets that prevent the timely transmission of high priority packets. Further HOL blocking is prevented by opening priority tunnels across the NoC, preventing lower priority packets from acquiring output ports that will be needed by high priority packets in the near future. Extensive evaluation using the R3 NoC under different traffic loads shows the effectiveness of the proposed technique and quantifies the required hardware overheads.