Xmesh：一个mesh-like片上网络拓扑结构  

Xmesh: A Mesh-Like Topology for Network on Chip

作　　者：朱晓静[1] 胡伟武[2] 马可[1] 章隆兵[2] 

机构地区：[1]中国科学技术大学计算机科学技术系,安徽合肥230027 [2]中国科学院计算技术研究所系统结构重点实验室,北京100080

出　　处：《软件学报》2007年第9期2194-2204,共11页Journal of Software

基　　金：Supported by the National Natural Foundation of China for Distinguished Young Scholars under Grant No.60325205(国家杰出青年基金);the National Natural Science Foundation of China under Grant No.60673146(国家自然科学基金);the National High-Tech Research and Development Plan of China under Grant Nos.2005AA110010;2005AAl19020(国家高技术研究发展计划(863));the National Basic Research Program of China under Grant No.2005CB321600(国家重点基础研究发展计划(973));the Natural Science Foundation of Beijing of China under Grant No.4072024(北京市自然科学基金);Knowledge Innovation Program of the Institute of Computing Technology;the Chinese Academy of Sciences under Grant Nos.20056240;20066012(中国科学院计算技术研究所知识创新课题)

摘　　要：针对片上网络(network on chip,简称NoC)的节点数量少、距离近、物理实现复杂度受到限制的特点,提出了一种新的Xmesh拓扑结构,并为该结构提出了XM路由算法.该结构在经典的mesh结构的基础上添加了两个对角线型的回边,缩短了节点间的距离,而且路由计算的复杂性不高,实现的复杂度基本没有增加.将Xmesh与经典的Mesh和Torus结构进行了理论分析比较,同时,在Popnet模拟器上基于均衡负载和热点负载两种负载模式进行性能比较.模拟结果表明,Xmesh平均延时不到Mesh结构的70%.对于均衡负载,当网络规模较小时,Xmesh的延时比Torus的更小;对于热点负载,当热点距离网络中心或者对角线比较近时,Xmesh的延时比Torus的小10%～30%.反之,其延时比Torus的大10%～30%.总的来说,Xmesh的性能与Torus比较接近,但其物理实现更为简单,Xmesh比Mesh结构的性能更好.Network on chip （NoC） has many characteristics, such as less nodes number, shorter distance between the cores, the need of less physical implementation difficulty, and so on. To satisfy the special need of the NoC, this paper presents a new topology named Xmesh and its routing algorithm called XM. This paper adds some diagonal edges on the Mesh topology to form Xmesh, sequentially reduce the average distances of the topology. Given the same network size, Xmesh has the same edge number with Torus topology, this paper compares the performance of Mesh, Xmesh and Torus topologies. A detailed theoretical analysis for Mesh, Xmesh and Torus topologies is given, and a simulation analysis based on the Popnet simulator using uniform traffic pattern and hotspot traffic pattern as benchmarks is also presented. As the simulation result shows, the average latencies of Xmesh and Torus topologies are less than 70% of the average latency of Mesh topology. For uniform traffic pattern, when the network size is small, the performance of Xmesh is better than Torus topology. For hotspot traffic pattern, when the hot node is near to the network center or the two diagonals, the latency of Xmesh is about 70%-90% of the latency of Torus topology, otherwise, the latency of Torus is about 70%-90% of the latency of Xmesh topology. In conclusion, Xmesh has a good performance just like Torus, but its physical implementation is simpler than Torus＇s, and both of which have a better performance than Mesh topology.

关 键 词：拓扑 路由算法 性能分析 负载模式 片上网络 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]