Research On Pivotal Technologies Of Network-on-Chip In Triplet-Based Architecture

With the continuous improvement of integrated circuit manufacturing and architecture design,microprocessor chip has entered the multi-core era.However,as the number of ex-ecution units increases,diminutive feature sizes exacerbate the impact of the interconnect delay,making the Network-on-chip(No C)become a critical bottleneck in meeting the per-formance of multi-core system.How to solve the problems of high latency,low bandwidth and high power consumption in No C is one of the serious challenges in the multi-core era.Triplet-based Architecture(TriBA)is a novel chip multiprocessor which directly sup-ports object-oriented at the hardware level.This dissertation presents deeply researches and discussions on some pivotal technologies of the TriBA No C,such as routing algorithm,router microarchitecture and physical layout.More specifically,the primary research and contribu-tions of this dissertation are as follows:(1)We propose a shortest-path routing algorithm for TriBA network(SPR4T).SPR4T adopts the distributed routing strategy,which computes the shortest-path at each hop based on the binary coding of the current node and the target node.Such binary computing will improve the efficiency of computation.Moreover,SPR4T establish a powerful coding system for TriBA network,whose elements has the same concept as the famous S₃group.Since the TriBA topology has symmetry for S₃transform,SPR4T leverage the cyclic permutation of S3 group to simplify the calculation.The experimental results show that SPR4T can achieve lower network latency and higher throughput against DDRA and SPORT.(2)We propose a novel router microarchitecture for TriBA network,called LA-Router.LA-Router optimizes the baseline router architecture via four measures:look-ahead routing strategy,minimized buffer strategy,segmented crossbar and injection control strategy.In particular,look-ahead routing strategy helps significantly cut down packet latency by re-ducing the number of pipeline stages in a router without packing more logic into each stage.Minimized buffer strategy effectively reduces the buffer usage and hence cuts down router energy and area.Segmented crossbar significantly reduces the router energy by using only the minimally needed wire segments to forward packet.Injection control strategy alleviates network congestion to a certain extent,thus reducing communication delay.The experimen-tal results show that LA-Router can not only effectively reduce the communication delay and power consumption of TriBA network,but also help to boost throughput.(3)We propose dynamic express virtual channel(EVC)for TriBA network.The con-struction of EVC requires the decision support of routing mechanism.Current EVC-based designs are almost based on dimension-ordered routing,however,dimension-ordered routing is not suitable for TriBA.In order to introduce EVC to TriBA network,we explore a dimen-sion judgment model,and on this basis,the FSP detection mechanism is designed to provide decision support for establishing express virtual channel.The experimental results show that our EVC-based design achieves superior performance over the baseline in terms of latency,throughput and energy.(4)We propose a tiled layout scheme to address the issue of physical implementation of Hybrid-TriBA network.In view of the characteristics of on-chip network traffic,we propose a Hybrid-TriBA network,which consists of two sub-networks:inter-core communication sub-network and memory sub-network.Subsequently,our proposed implementation design for the two sub-networks involves tiled placement of inter-core communication sub-network in a Manhattan-like grid with the remaining space filled with memory sub-network.The ex-perimental results show that this tiled layout scheme is feasible,and more importantly,the Hybrid-TriBA network has obvious advantages in terms of average network latency,through-put and power consumption compared with the single-TriBA network.