Adaptive Multicast Wormhole Routing in 2D Mesh Multicomputers

The issues of adaptive multicast wormhole routing in 2D mesh multicomputers are studied. Three adaptive multicast wormhole routing strategies are proposed and evaluated. The methods include minimal partially adaptive, minimal fully adaptive, and nonminimal adaptive routing. All the algorithms are shown to be deadlock-free. A study has been conducted that compares the performance of these multicast algorithms. The results show that the minimal fully adaptive routing method creates the least traffic; however, double vertical channels are required in order to avoid deadlock. The nonminimal routing algorithm exhibits the best adaptivity, although it creates more network traffic than the other methods.     

Adaptive Fault-Tolerant Multicast in Hypercube Multicomputers

Fault-tolerant message routing mechanism is a key to the performance of reliable multicomputers. Multicast refers to the delivery of the same message from a source node to an arbitrary number of destination nodes. This paper presents two types of partially adaptive fault tolerant multicast algorithms. The Type A algorithm can deliver messages to all destinations through shortest paths if each fault-free node has at most one faulty neighbor. The Type B algorithm can deliver messages to all destinations if the total number of faulty links and faulty nodes is less than the dimension of the hypercube. The proposed algorithms have the following important features: they are distributed, they only require local information to determine the paths, and they need very little additional message overhead. The performance of the algorithms, measured by the traffic created by the communication, is very close to that in fault-free hypercubes.     

用最优通路矩阵实现超立方体多处理机系统的容错路由

针对拓扑结构为超立方体的多处理机系统提出了最优通路矩阵（ＯＰＭ）的概念,并约出了一个基于最优通路矩阵的路由算法。存储于超产方体各节点中的最优通路矩阵记录系统中的故障信息,用于判定消息的源节点和目的节点之间是否存在最优通路（长度等于两节点间Ｈａｍｍｉｎｇ距离的通路）。对于ｎ维超方立体,每个节点所需的存储开销为ｎ＾２个字,基于最优通路矩阵的路由算法所选的通路的长度不超过两点间的Ｈａｍｍｉｎｇ距离加２。     

超立方体多处理机系统中基于扩展安全向量的容错路由

针对超立方体结构的多处理机系统中存在链路故障的情况,修改了吴杰提出的安全向量的概念,提出了扩展安全向量的概念,并给出了一个基于扩展安全向量的容错路由算法,与基于安全向量的路由算法相比,基于扩展安全向量的路由算法搜索最优通路的能力有了非常大的提高,即使故障数较多时,它仍能保证把绝大多数源、目的节点间有最优通路和消息沿最优通路传递。超立方体结构中各节点扩展安全向量的赋值可以通过ｎ－１轮邻接点的信息交换     

Optimal Fully Adaptive Minimal Wormhole Routing for Meshes

A deadlock-free fully adaptive minimal routing algorithm for meshes that is optimal in the number of virtual channels required and in the number of restrictions placed on the use of these virtual channels is presented. It is also proved that, ignoring symmetry, this routing algorithm is the only fully adaptive routing algorithm with uniform routers that achieves both of these goals. This new algorithm requires only 4n-2 virtual channels for an n-dimensional mesh. In addition, if more than the minimum number of virtual channels is available, the routing algorithm can use these additional channels with the fewest possible number of restrictions. The proofs are first presented for the 2D mesh and then generalized to n-dimensional meshes.     

超立方体互连网络自适应简捷盲寻径搜索算法

根据n-cube超立方体互连网络的并行特点，分析了任意当前结点相邻集合类的求解方法，并给出一种自适应优化盲寻径搜索算法，即通过任一当前结点的Hamming距离相邻测度，寻找从任一始发结点到目标结点的所有可能的自适应盲寻径优化算法．     

基于超立方体的静态任务调度

该文给出一个基于超立方体的静态任务调度算法.在算法的设计中,首先建立了任务优先级表和处理机优先级表,任务在调度时总是顺次调度高优先级任务,然后再从处理机优先级表中选择能使该任务最早开始执行的处理机.最后,分别给出了基于LU分解的任务图与随机生成的任务图的调度结果.     

Synchronous Load Balancing in Hypercube Multicomputers with Faulty Nodes

This paper presents a new dynamic load-balancing algorithm for hypercube multicomputers with faulty nodes. The emphasis in our method is on obtaining global load information and performing task migration using “short paths” in a synchronous manner so that a minimal amount of communication overhead is required. To accomplish this, we present an algorithm for constructing a new logical topology from a hypercube topology with faulty nodes. This new topology is used to obtain the global load information and to perform task migration. Simulation results are used to evaluate the performance of our dynamic load balancing method when compared with previous methods     

Mesh网络耐故障虫孔路由

耐故障是互连网络设计中的一个重要问题。本文提出了一种新的耐故障路由算法,并将其应用于使用虫孔交换技术的Mesh网络。由于使用了较低的路由限制,这一算法具有很强的自适应性,可以在各种不同故障域的Mesh网络中保持路由的连通性和无死锁性;由于使用了最小限度的虚拟通道,这一算法所需的缓冲器资源很少,非常适宜构建低成本的耐故障互连网络;由于根据本地故障信息进行绕行故障节点的决策,这一算法的路由决策速度较快并且易于在互连网络中实现。最后网络仿真试验显示,这一算法具有良好的平滑降级使用的性能。     

Hierarchical Scheduling of Dynamic Parallel Computations on Hypercube Multicomputers

In this paper a hierarchical task scheduling strategy for assigning parallel computations with dynamic structures to large hypercube multicomputers is proposed. Such computations represent a wide range of recursive and divide/conquer algorithms for which structure of the problem varies dynamically. To achieve load balancing and reduce processor contentions, the system is divided into multiple regions of processors for which the first level of scheduling is done by the host computer that spreads out the initial computations into these regions. The second level scheduling is done by a set of median processors of these regions which enable the processors of their regions to optimally balance the dynamically created load and to communicate with each other with reduced overhead. The results of an extensive simulation study are presented that exhibit the performance of the proposed strategy under different loading conditions, varying degrees of depth and parallelism, and communication costs. The proposed dual-level hierarchical scheduling is shown to outperform a well known distributed scheduling strategy.     

一种基于Wormhole Routing的寻径技术*

先锋网(Pionet)是一种具有自主知识产权的网络互连结构,将介绍先锋网寻径技术——先锋信令寻径技术(Pionet-Routing)。先锋网上层协议简单,实验数据显示：该网络系统效率高,适合于进行机群科学计算。     

虫孔网络中的自适应路由算法

互连网络是大规模并行计算机的重要组成部分,路由算法是其中决定网络性能的重要因素,自适应路由算法视网络工作状态可以在源到目的结点之间存在的多条路径中选择合适的一条传送消息,因此选径的灵活性和通道利用率高,提高了网络效率,增强了网络容错能力。文中在直接网络结构基础上对采用虫孔路由的自适应算法进行讨论,给出了一个总结综述。     

Broadcasting on Meshes with Wormhole Routing

We address the problem of broadcasting on two-dimensional mesh architectures with an arbitrary (non-power-of-two) number of nodes in each dimension. It is assumed that such mesh architectures employ cut-through or wormhole routing. The primary focus is on avoiding network conflicts in the various proposed algorithms. We give algorithms for performing a conflict-free minimum-spanning tree broadcast, a pipelined algorithm that is similar to Ho and Johnsson's EDST algorithm for hypercubes, and a novelscatter–collectapproach that is a natural choice for communication libraries due to its simplicity. Results obtained on the Intel Paragon system are included.     

A Performance Model of Adaptive Wormhole Routing in k-Ary n-Cubes in the Presence of Digit-Reversal Traffic

Several analytical models of fully adaptive routing in wormhole-routed k-ary n-cubes under the uniform traffic pattern have recently been proposed in the literature. Although the uniform reference model has been widely used by researchers, it is not always true in practice as there are many applications that exhibit traffic nonuniformity. There has hardly been any study that describes an analytical model of fully adaptive routing under nonuniform traffic conditions. This paper describes the first analytical model of fully adaptive routing in k-ary n-cubes in the presence of nonuniform traffic generated by the digit-reversal permutation, which is an important communication operation found in many matrix computation problems. Results obtained through simulation experiments confirm that the model predicts message latency with a good degree of accuracy under different working conditions.     

基于虫洞路由的无HoL阻塞环形架构

提出一种基于虫洞路由的无HoL阻塞环形片上互联网络架构,实现了在不消耗太多资源的前提下,用一级流水线以类虚拟输出队列的方式完全消除队头阻塞和死锁。评估不同参数下该环形架构的性能,与CELL EIB等环形实现相比,该架构以单数据包仅11周期最小延时的性能明显优于其他环形架构,同时最大吞吐率达到25.6 Gb/s。     

网络中的蛀孔寻径技术

文章从网络通信的角度研究了大规模并行计算机系统(Massivelyparallelprocessingsystem)中实时网络的通信问题,介绍了蛀孔寻径技术的原理和相应的算法。     

一种针对虫洞攻击的安全路由方法

Ad Hoc网络的虫洞攻击危害较大且难以防御。为此,提出一种基于时间和跳数的安全路由方法。将时间差值和跳数差值作为2个限制量,分别与规定值进行比较,判断并抛弃可能存在虫洞攻击的路由,并选择相对安全的路由,建立可信的数据传输通道。NS2仿真结果表明,该方法可提高虫洞攻击的检测率,降低数据传输的丢包率。     

交换超立方网中的最短路径路由算法

针对交换超立方网络的最短路由问题,提出一个交换超立方网中的最短路径路由算法.利用图论的方法,通过引进子网的概念,研究交换超立方网的拓扑性质,给出节点各边可进行最短路径路由的充要条件,得到其时间复杂度为O(s+t)2).理论分析和仿真结果表明,该算法可输出交换超立方网中任意两节点间的一条最短路径.     

Rearrangeable Circuit-Switched Hypercube Architectures for Routing Permutations

Rearrangeable hypercube architectures and routing algorithms are developed to realize arbitrary permutations in circuit switching. We prove that if each connection between two neighboring nodes consists of two pairs of links (two full-duplex communication lines), the hypercube can handle two arbitrary permutations simultaneously. We also prove that a hypercube is rearrangeable if one additional pair of links is provided in any one dimension of connections.