关键词： Multiprocessing systems  

摘要： Global virtual time (GVT) is used in the time-warp synchronization mechanism to perform irrevocable operations and to reclaim storage. GVT computation is much simpler in shared-memory multiprocessors than in message-passing systems because they normally guarantee that no two processors will observe a set of memory operations as occurring in different orders. Exploiting this fact, an efficient, asynchronous, shared-memory GVT algorithm is proposed and its correctness is proven. A new mechanism called on-the-fly fossil collection which enables efficient storage reclamation for simulations containing large numbers is also proposed. It can be used in time-warp systems executing on shared-memory or message-based machines.

关键词： 多处理器   容错执行软件   航空电子系统   MTE  

摘要： 介绍了多处理器容错执行软件（ＭＴＥ）的设计及其结构特点；阐述了ＭＴＥ软件如何通过任务转移实现系统容错功能及对应用软件的简化，以提高应用软件的维护性和质量。

关键词： memory bank contention   memory delays   parallel machine models   performance analysis   parallel algorithms   shared memory   multiprocessors  

摘要： For years, the computation rate of processors has been much faster than the access rate of memory banks, and this divergence in speeds has been constantly increasing in recent years. As a result, several shared-memory multiprocessors consist of more memory banks than processors. The object of this paper is to provide a simple model (with only a few parameters) for the design and analysis of irregular parallel algorithms that will give a reasonable characterization of performance on such machines. For this purpose, we extend Valiant's bulk-synchronous parallel (ssp) model with two parameters: a parameter for memory bank delay, the minimum time for servicing requests at a bank, and a parameter for memory bank expansion, the ratio of the number of banks to the number of processors. We call this model the (d, x)-BSP. We show experimentally that the (d, x)-BSP captures the impact of bank contention and delay on the GRAY C90 and J90 for irregular access patterns, without modeling machine-specific details of these machines. The model has clarified the performance characteristics of several unstructured algorithms on the GRAY C90 and J90, and allowed us to explore tradeoffs and optimizations for these algorithms. In addition to modeling individual algorithms directly, we also consider the use of the (d, x)-BSP as a bridging model for emulating a very high-level abstract model, the Parallel Random Access Machine (PRAM). We provide matching upper and lower bounds for emulating the EREW and QRQW PRAMS on the (d, x)-BSP.

关键词： average fault tolerance   deterministic fault tolerance   fault-tolerant multiprocessors   linear error-correcting codes   matching   network flow   node-covering   VLSI layout   reconfiguration  

摘要： Structural fault tolerance (SFT) is the ability of a multiprocessor to reconfigure around faulty processors or links in order to preserve its original processor interconnection structure. In this paper, we focus on the design of SFT multiprocessors that have low switch and link overheads, but can tolerate a very large number of processor faults on the average. Most previous work has concentrated on deterministic k-fault-toterant (k-FT) designs in which exactly k spare processors and some spare switches and links are added to construct multiprocessors that can tolerate any k processor faults. However, after k faults are reconfigured around, much of the extra links and switches can remain unutilized. It is possible within the basic node-covering framework, which was introduced by Dutt and Hayes as an efficient k-FT design method, to design FT multiprocessors that have the same amount of switches and [inks as, say, a two-FT deterministic design, but have s spare processors, where s much greater than 2, so that, on the average, k = theta(s) (k less than or equal to s) processor failures can be reconfigured around. Such designs utilize the spare link and switch capacity very efficiently, and are called probabilistic FT designs. An elegant and powerful method to construct covering graphs or CG's, which are key to obtaining the probabilistic FT designs, is to use linear error-correcting codes (ECCs). We show how to construct probabilistic designs with very high average fault tolerance but low wiring and switch overhead using ECCs like the 2D-parity, full-two, 3D-parity, and full-three codes. This design methodology is applicable to any multiprocessor interconnection topology and the resulting FT designs have the same node degree as the non-FT target topology. We also analyze the deterministic fault tolerance for these designs and develop efficient layout strategies for them. Finally, we compare the proposed probabilistic designs to some of the best deterministic and probab

关键词： 回波抵消   多机系统   语声信号处理  

摘要： 介绍了多处理器的构成及其在３０路回波抵消器中的应用。在分析比较了几种多处理器控制方案的基础上，根据３０路回波抵消器的特点，提出了一种改进的多处理器逻辑控制方案，在３０路回波抵消器的实际应用中取得了较好的效果。

关键词： 示波器   高采样率示波器   多处理器  

摘要： 基于多处理器的高采样率示波器原作者：Ｒ．ＳｃｏｔＢｒｕｎｔｏｎＨＰ５４６１５Ｂ和５４６１６Ｂ示波器将专利高速采样技术与ＤＳＰ能力融为一体，通过验证的用户界面，提供了先进的功能特性。ＨＰ５４６１５Ｂ和５４６１６Ｂ示波器的设计着力于在ＨＰ５４６００系列产...

关键词： 图   立方体   多处理器   容错路由   最优路由  

摘要： 对n-立方体结构的多处理器系统，本文考查了出故障的处理器非常集中时的容错路由对策，给出了一种判断出故障的处理器是否全部或绝大部分集中于某一（n—1）-子立方体的方法，证明了当差错非常集中时任意两个有效处理器之间可在线性时间（即o(n)时间）内找到最光或接近最优路由的有效路由．

关键词： 多处理器   AutoCAD   应用程序   Web服务器   电源管理   存储器带宽   软件   无人值守   UPS电源   优先权  

摘要： APC最近宣布与UPS捆绑销售的Power Chute plus 5.0版网络电源管理软件具有前所未有的强大功能,可实现网络电源保护的无人值守。APC大中国区总经理程小丹先生说:“这是具有前所未有的强大功能的电源管理软件。此版软件的推出,意味着实现了稳定可靠的无人值守网络电源保护。尤其对用于Web服务器保护的UPS用户来说,APC的捆绑有Power Chute Plus 5.0电源管理软件的UPS是其最理想的选择。”

关键词： .iteration   redundant   iterative   determining   OPTIMIZING   synchronizations   strongly connected   self-timed   synchronization graph   synchronization overhead   multiprocessor implementations  

摘要： This paper is concerned with multiprocessor implementations of embedded applications specified as iterative dataflow programs in which synchronization overhead call be significant, We develop techniques to alleviate this overhead by determining a minimal set of processor synchronizations that are essential for correct execution, Our study is based in the context of self-timed execution of iterative dataflow programs, An iterative dataflow program consists of a dataflow representation of the body of a loop that is to be iterated an indefinite number of times;dataflow programming in this form has been studied and applied extensively, particularly in the context of signal processing software, Self-timed execution refers to a combined compile-time/run-time scheduling strategy in which processors synchronize with one another based only on interprocessor communication requirements, and thus, synchronization of processors at the end of each loop iteration does not generally occur, We introduce a new graph-theoretic framework based on a data structure called the synchronization graph for analyzing and optimizing synchronization overhead in self-timed, iterative dataflow programs, We show that the comprehensive techniques that have been developed for removing redundant synchronizations in noniterative programs can be extended in this framework to optimally remove redundant synchronizations in our context, We also present an optimization that converts a feedforward dataflow graph into a strongly connected graph in such a way as to reduce synchronization overhead without slowing down exeuction.

关键词： circular lists   critical sections   hot-spot contention   linked lists   multiprocessors   mutual exclusion   tree of locks  

摘要： Mutual exclusion in shared-memory multiprocessors is realized by employing a lock to determine the processor among those which compete for the critical section. Accesses to such a mutual exclusion lock may create heavy synchronization traffic and/or serious contention over the network, thereby degrading system performance considerably. In this paper, we introduce an efficient scheme which keeps synchronization traffic low and avoids serious hot-spot contention. This is made possible by constructing a circular list of the processors waiting for the critical section and by dispersing accesses to the lock. Extensive simulation of the proposed approach was conducted and the lower bound on the elapsed time was derived. Our simulation results demonstrate that the proposed scheme indeed achieves better performance than prior techniques, with its elapsed time close to the lower bound for the whole range of simulated system sizes, thus promising good scalability for large systems.