We propose a network-on-chip (NoC)-based whole system design, whose communication architecture is compatible with the advanced microcontroller bus architecture advanced extensible interface 4 (AXI4) protocol and supports high-performance multiple quality-of-service (QoS) schemes. In our system, the network interface (NI) between the NoC and the master/slave node is proposed to make the NoC architecture independent from the AXI4 protocol via message format conversion between the AXI4 signal format and the packet format, offering high flexibility to the NoC design. Besides, a QoS inheritance mechanism is applied in the slave-side NI to support QoS during packets’ round-trip transfer in the NoC. The NoC system contains time-division multiplexing (TDM) and virtual channel (VC) subnetworks to apply multiple QoS schemes to AXI4 signals with different QoS tags, and the NI is responsible for signals distribution between two subnetworks. Besides, a traffic converter is proposed in each NI to balance the traffic between the two subnetworks when necessary. The experimental results show that our proposed architecture ensures a high-throughput and low-latency NoC system. By applying the traffic converter, the packet latency can be improved.

We present a smart communication service called Advance Virtual Channel Reservation (AVCR) to provide a highway to target packets, which can greatly reduce their contention delay in NoC. AVCR takes advantage of the fact that we can know or predict the destination of some packets ahead of their arrival at the network interface (NI). Exploiting the time interval before a packet is ready, AVCR establishes an end-to-end highway from the source NI to the destination NI. This highway is built up by reserving the virtual channel (VC) resources ahead of the target packet transmission and offering priority service to flits in the reserved VC in the wormhole router, which can avoid the target packets' VC allocation and switch arbitration delay. Additionally, optimization schemes are proposed to increase resources utilization and system performance. We evaluate AVCR with GEM5 full-system simulations by using 24 benchmarks in PARSEC and OMP2012. Compared to the state-of-art mechanisms and the priority-based mechanism, experimental results show that our mechanism can significantly reduce the target packets' transfer latency and thus effectively decrease the average region-of-interest (ROI) time by 18.1 percent (maximally by 29.4 percent) across all benchmarks.

We propose an admission control method in Network-on-Chip (NoC) with a centralized Artificial Neural Network (ANN) admission controller, which can improve system performance by predicting the most appropriate injection rate of each node via the network performance information. In the online control process, a data preprocessing unit is applied to simplify the ANN architecture and make the prediction results more accurate. Based on the preprocessed information, the ANN predictor determines the control strategy and broadcasts it to each node where the admission control will be applied. Compared to the previous work, our method builds up a high-fidelity model between the network status and the injection rate regulation. The full-system simulation results show that our proposed method can enhance application performance by 17.8% on average and up to 23.8%.

We present a smart communication service called Advance Virtual Channel Reservation (AVCR) to provide a highway to packets, which can greatly reduce their contention delay in NoC. AVCR takes advantage of the fact that we can know or predict the destination of some packets ahead at the network interface (NI). Exploiting the time slack before a packet is ready, AVCR establishes an end-to-end highway from the source NI to the destination NI. This highway is built up by reserving virtual channel (VC) resources ahead and at the same time, offering priority service to those VCs in the router, which can therefore avoid highway packets' VC allocation and switch arbitration delay in NoC. Additionally, optimization schemes are developed to reduce VC overhead and increase highway utilization. We evaluate AVCR with cycle-accurate full-system simulations in GEM5 by using all benchmarks in PARSEC. Compared to the state-of-art mechanisms and the priority based mechanism, experimental results show that our mechanism can significantly reduce the target packets' transfer latency and effectively decrease the average region-of-interest (ROI) time by 22.4% (maximally by 29.4%) across PARSEC benchmarks.