On-chip Network Service Quality Assurance Study

Network-on-chip is a new infrastructure of system-on-chip (NoC). Usually the services in NoC has two types: Best Effort and Guaranteed Services. The guaranteed services of QoS include hard guarantees (Hard GT) and statistical guarantees (Soft GT). In this paper, the QoS-NoC system based on Hard GT is designed, by reserving resources, i.e. Connection-oriented. Using circuit switching to set up the connections is used to offer hard GT. Once a connection is set up, its performance is assured due to no contention exists. But if the connection request is failed, the transmission delay and throughtput can not be assured. In this paper, we improve the network performance by optimizing the routing algorithm and network infrastructure to increase the success probobility of setting connections, while the number of virtual channels are limited. We propose the dualnet-QoS-NoC, DY-QoS-NoC and DY-dualnet-QoS-NoC machanism, and the performances are verified on the QoS-NoC simulators.The main contributions in this paper are as follows:(1) Develope a MSNS-QoS-NoC simulator based on SystemC language, which offers multi-levels of hard guaranteed service.(2) Use dual-subnets infrastructure, i.e. dualnet-QoS-NoC, to improve the success probobility of connection requests, thus effectively decreases the packet delay and increases the throughput of NoC .(3) Propose the DY-QoS-NoC infrastructure by using dynamic virtual channel allocation strategies in the NoC to improve the success probobility of setting connections and to reduce the chip area.(4) Designed the DY-dualnet-QoS-NoC machamism by combining dual-subnets infrastructure and dynamiclly virtual channel allocation strategies in the NoC system. The success probobility of setting connections is improved and the chip area is saved, while and the transmission delay is recuded due to the balance of the traffic flows.