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In the movement from a multi‐core to a many‐core era, cores count on the chip increases quickly thus interconnect plays a large role in achieving the desired performance. Network‐on‐chip (NoC) is the most widely used interconnect as a scalable alternative for traditional shared bus in many‐core chips. As the dimensions of mesh‐based NoC increase, routers and links serve as a major part to achieve the desired performance and low‐latency communication between cores. In this study, the authors propose an arbitration mechanism for NoC that leads to a reduction in congestion delay in routers as well as the network latency. The proposed mechanism is compatible with the bypass and baseline pipeline in routers. System simulations with Noxim demonstrate reduction in latencies and power consumption using different routing algorithms for 4×4,8×8 and 16×16 mesh topologies, as compared with a baseline router. [ABSTRACT FROM AUTHOR]

Network-on-chip (NoC) architecture is regarded as a solution for future on-chip interconnects. However, the performance advantages of conventional NoC architectures are limited by the long latency and high power consumption due to multi-hop long-distance communication among processing elements. To solve these limitations, we employed on-chip wireless communication as express links for transferring data so that transfer latency can be reduced. A hybrid NoC architecture utilizing both wired and wireless communication approaches is proposed in this paper. We also devised a deadlock-free routing algorithm that is able to make efficient use of the incorporated wireless links. Moreover, simulated annealing optimization techniques were applied to find optimal locations for wireless routers. Cycle-accurate simulation results showed a significant improvement in transfer latency. Area and power consumption analysis demonstrates the feasibility of our proposed NoC architecture. [ABSTRACT FROM AUTHOR]

Efficient on-chip communication is necessary for exploiting enormous computing power available on a many-core chip. Routing algorithms play a major role for the communication quality and performance of the on-chip interconnection networks. This paper proposes TagNoC, as an on-chip network router architecture with novel hybrid routing approach which reduces latency and power consumption at a fixed cost based on information redundancy. TagNoC is a hybrid routing approach which combines the source and distributed routing methods together. While eliminating packet routing in each router, TagNoC determines the forwarding output port in parallel with input buffering. For a marginal cost increase in header size, as compared to distributed routing techniques, routing latency can be hidden while eliminating power consuming portion of the routing, increasing router throughput and decreasing latency. The proposed TagNoC router is compared to baseline router with distributed routing implementation on a 16-node CMP mesh. Physical implementation of all routers is modeled using synthesized RTL, detailed area analysis, and accurate channel models. Performance evaluation is also carried out utilizing RTL simulation and detailed power analysis on both synthetic and application traffic is performed using post-synthesis gate-level simulation. The simulation results illustrate that TagNoC outperforms as compared to baseline distributed architecture and other source routing methods in terms of power, latency, and throughput. [ABSTRACT FROM AUTHOR]

Abstract: Adaptive routing algorithms have been employed in interconnection networks to improve network throughput and provide better fault tolerance characteristics. However, they can harm performance by disturbing any inherent global load balance through greedy local decisions. This paper proposes a novel scalable load balancing congestion-aware Network-on-Chip (NoC) architecture that not only enhances network transmission performance while maintaining a feasible implementation cost, but also improves overall network throughput for various traffic scenarios. This congestion control scheme which consists of dynamic input arbitration and adaptive routing path selection is proposed to balance global traffic load distribution so as to alleviate congestion caused by heavy network activities. Furthermore, faulty links information can be broadcasted by existing congestion management control signals to prevent packets from routing through defected areas in order to eliminate potential heavy congestion situations around these regions. Experimental results show that throughput is improved dramatically while maintaining superior latency performance for various traffic patterns. Compared to a baseline router, the proposed congestion management mechanism requires negligible cost overhead but provides better throughput for both mesh and diagonally-linked mesh NoC platforms. [Copyright &y& Elsevier]

2D-NoCs have been the mainstream approach used to interconnect multi-core systems. 3D-NoCs have emerged to compensate for deficiencies of 2D-NoCs such as long latency and power overhead. A low-latency routing algorithm for 3D-NoC is designed to accommodate high-speed communication between cores. Both simulation and analytical models are applied to estimate the communication latency of NoCs. Generally, simulations are time-consuming and slow down the design process. Analytical models provide, within a fraction of the time, nearly accurate results which can be used by simulation to fine-tune the design. In this paper, a high performance and adaptive routing algorithm has been proposed for partially connected 3D-NoCs. Latency of the routing algorithm under different traffic patterns, different number of elevators and different elevator assignment mechanisms are reported. An analytical model, tailored to the adaptivity of the algorithm and under low traffic scenarios, has been developed and the results have been verified by simulation. According to the results, simulation and analytical results are consistent within a 10 percent margin. [ABSTRACT FROM AUTHOR]

3D ICs can take advantage of a scalable communication platform, commonly referred to as the Networks-on-Chip (NoC). In the basic form of 3D-NoC, all routers are vertically connected. Partially connected 3D-NoC has emerged because of physical limitations of using vertical links. Routing is of great importance in such partially connected architectures. A high-performance, fault-tolerant and adaptive routing strategy with respect to the communication flow among the cores is crucial while freedom from livelock and deadlock has to be guaranteed. In this paper we introduce a new routing algorithm for partially connected 3D-NoCs. The routing algorithm is adaptive and tolerates the faults on vertical links as compared to the predesigned routing algorithms. Our results show a $40-50\%$ improvement in the fraction of intact inter-level communications when the fault tolerant algorithm is used. This routing algorithm is light-weight and has only one virtual channel along the $Y$ dimension. [ABSTRACT FROM AUTHOR]

Abstract: 3-D Networks-on-Chip (NoCs) have been proposed as a potent solution to address both the interconnection and design complexity problems facing future System-on-Chip (SoC) designs. In this paper, two topology-aware multicast routing algorithms, Multicasting XYZ (MXYZ) and Alternative XYZ (AL+XYZ) algorithms in supporting of 3-D NoC are proposed. In essence, MXYZ is a simple dimension order multicast routing algorithm that targets 3-D NoC systems built upon regular topologies. To support multicast routing in irregular regions, AL+XYZ can be applied, where an alternative output channel is sought to forward/replicate the packets whenever the output channel determined by MXYZ is not available. To evaluate the performance of MXYZ and AL+XYZ, extensive experiments have been conducted by comparing MXYZ and AL+XYZ against a path-based multicast routing algorithm and an irregular region oriented multiple unicast routing algorithm, respectively. The experimental results confirm that the proposed MXYZ and AL+XYZ schemes, respectively, have lower latency and power consumption than the other two routing algorithms, meriting the two proposed algorithms to be more suitable for supporting multicasting in 3-D NoC systems. In addition, the hardware implementation cost of AL+XYZ is shown to be quite modest. [Copyright &y& Elsevier]