PVM应用移植到MPI问题的探讨

消息传递方式是广泛应用于一些并行机,特别是分布存储并行机的一种模式。ＰＶＭ（ＰａｒａｌｌｅｌＶｉｒｔｕａｌＭａｃｈｉｎｅ）和ＭＰＩ（ＭｅｓｓａｇｅＰａｓｓｉｎｇＩｎｔｅｒｆａｃｅ）都是目前是广受欢迎的基于消息传递的并行程序库,其中ＰＶＭ的消息传递接口,因其简单性,而没有给用户最大的灵活性以实现最佳的性能：为此,消息传递标准的讨论会工作组制定了消息传递接口ＭＰＩ标准,为ＰＶＭ实现最佳性能提供了可能。该文通过对ＰＶＭ和ＭＰＩ的比较,指出了从ＰＶＭ应用移植到ＭＰＩ应用时有利的方面和潜在的缺陷。如果一个应用程序能避开这些缺陷的影响,那么它就能够从移植中提高通信的性能,从而提高其分布式计算的性能。     

网络环境中MPI和PVM的分析与比较

消息传递接口(MessagePassingInterface,MPI)和并行虚拟机(ParallelVirtualMachine,PVM)是两种广泛应用的网络分布式并行计算环境。论文首先介绍了消息传递接口和并行虚拟机两者各自的起源和特点,然后在此基础上从可移植性、点对点通信、集体通信、资源管理和容错能力等多方面分析和比较了这两者的功能特点。     

基于PVM的安全线程机制的研究

PVM并行虚拟机是一种广为使用的分布并行消息库,使用进程作为并行任务的基本单位。但是PVM不支持安全的线程机制。在研究借鉴先前研究经验的基础上,研究支持PVM线程安全的机制,在PVM库和POSIX线程库之上设计了支持PVM线程应用的库PTL,使基于进程的消息传递模型可以基于线程来实现。阐述了其设计原理,给出了程序设计示例,最后给出总结。     

基于快速消息传递的高性能PVM

并行虚拟机(parallelvirtualmachine,简称PVM)是并行工作站机群系统中流行的并行软件环境之一.分析了PVM的实现机制,指出PVM低效的原因,并给了基于高速精简通信层调整消息传递(fastmessagepassing,简称FMP)的高性能PVM(high-performancePVM,简称HPVM)的详细设计和实现.     

基于MapReduce的互联网拓扑特征参数算法研究

针对传统单机算法在计算大规模互联网拓扑特征参数时效率低的问题,基于MapReduce分布式计算框架对网络拓扑特征参数算法进行研究。通过分析单机图算法并行移植时存在的问题,提出了图算法并行化设计的原则和消息传递机制;根据设计原则和消息传递机制,为4个网络拓扑参数设计了并行算法。实验证明,并行的拓扑参数算法能够有效提高计算效率,且具备良好的可扩展性。     

若干发展的消息传递界面：PVMPI，IMPI与FT—MPI

本文介绍了诸如PVMPI、IMPI的改进型消息传递界面(在异构环境中不同的MPI实现能够彼此互操作)，也介绍了具有容错能力的FI—MPI。分析了MPI的特征和体系结构及其性能。     

基于网格的消息传递接口的实现:MPICH-G2

MPI(消息传递接口)作为一种著名的底层并行编程模型已被提出来作为网格编程的基础。描述了基于网格的消息传递接口的实现MPICH-G2，它基于MPICH和Gllobus工具包实现，在启动和管理中隐藏了异构性，具有良好的异构通讯性能。用一个例子说明如何在一个由Globus搭建的计算网格环境中通过MPICH-G2来创建和执行MPI计算。     

SIFT特征分布式并行提取算法

SIFT(scale invariant feature transform)特征在物体检测和识别、图像配准与融合、纹理识别、场景分类、人脸检测、图像检索、三维重建、数字水印、影像追踪等领域具有广泛应用,但存在计算量大、消耗时间长的缺点.基于消息传递机制,采用数据并行策略,提出了在PC机群或COW(cluster ofworkstation)上提取图像SIFT特征的分布式并行算法(DP-SIFT算法):根据特征空间-高斯尺度金字塔的特点提出了高度宽度受限的数据块划分算法,设计了数据分配和特征调整方法;研究了数据块划分和数据发送方法对通信时间的影响,提出了基于消息传递机制的并行图像处理中数据块划分与数据发送方式协同对通信优化的策略;实验结果表明DP-SIFT算法具有良好的加速性能和较高的处理器利用效率,千兆以太网连接32核的PC机群系统图像规模为1024×768时,加速比和处理器效率分别可以达到20和0.6;图像规模为2048×1536时可达18和0.56.     

主动消息与MPI

本文详细分析了消息传递的开销问题,并对可降低开销的一种机制：主动消息进行了深入探计,在此基础上给出了将主动消息引入ＭＰ少基于主动消息实现ＭＰＩ的原型。     

大规模并行计算机系统并行性能模拟技术研究

性能模拟技术是计算机系统性能评价的重要手段.介绍了面向大规模并行计算机系统以及消息传递应用程序的并行性能模拟技术,总结了相关的关键技术和国内外研究现状.对几个代表性的并行模拟器系统进行了详细介绍.结合并行计算机系统和应用的发展趋势,讨论了未来并行模拟器设计、实现面临的问题和可能的解决方案.     

基于多核集群系统的并行编程模型的研究

并行计算技术是计算机技术发展的重要方向之一。当前并行程序模型主要有消息传递模型和共享存储模型两种。随着处理器多核技术的发展,在一枚多核处理器中集成两个或多个完整的计算引擎（内核）,并充分利用多核计算机的特性,发挥多核计算机的性能成为一个很重要的研究方向。介绍一种新的MPI实现机制,这种机制集成了共享存储模型和消息通信模型的优点,在节点内使用共享存储模型,在节点间使用消息传递模型,并且通过自动生成线程级的任务来获得更好的性能。．     

High-performance message-passing over generic Ethernet hardware with Open-MX

In the last decade, cluster computing has become the most popular high-performance computing architecture. Although numerous technological innovations have been proposed to improve the interconnection of nodes, many clusters still rely on commodity Ethernet hardware to implement message-passing within parallel applications. We present Open-MX, an open-source message-passing stack over generic Ethernet. It offers the same abilities as the specialized Myrinet Express stack, without requiring dedicated support from the networking hardware. Open-MX works transparently in the most popular MPI implementations through its MX interface compatibility. It also enables interoperability between hosts running the specialized MX stack and generic Ethernet hosts. We detail how Open-MX copes with the inherent limitations of the Ethernet hardware to satisfy the requirements of message-passing by applying an innovative copy offload model. Combined with a careful tuning of the fabric and of the MX wire protocol, Open-MX achieves better performance than TCP implementations, especially on 10 gigabit/s hardware.     

有限差分离散模型分布并行计算支持库技术

本文研究实现了一个面向有限差分离散模型的分布并行计算支持库YHLIB。YHLIB库基于MPI消息传递接口设计实现,通过提供有限差分离散模型并行计算接口支持计算区域分解、域间通信、域内通信、循环下标转换、分布式I/O、动态负载平衡等功能,封装了并行计算实现细节,提高了并行程序开发效率。抽象模型实现和实际应用测试表明,YHLIB具有较高的并行效率。     

Efficient scheduling of MPI applications on networks of workstations

The availability of a large number of workstations connected through a network can represent an attractive option for high-performance computing for many applications. The message-passing interface (MPI) software environment is an effort from many organisations to define a de facto message-passing standard. In other words, the original specification was not designed as a comprehensive parallel programming environment and some researchers agree that the standard should be preserved as simple and clean as possible. Nevertheless, a software environment such as MPI should have somehow a scheduling mechanism for the effective submission of parallel applications on network of workstations. This paper presents an alternative lightweight approach called Selective-MPI (S-MPI), which was designed to enhance the efficiency of the scheduling of applications on an MPI implementation environment.     

A novel strategy for building interoperable MPI environment in heterogeneous high performance systems

Breakthrough advances in microprocessor technology and efficient power management have altered the course of development of processors with the emergence of multi-core processor technology, in order to bring higher level of processing. The utilization of many-core technology has boosted computing power provided by cluster of workstations or SMPs, providing large computational power at an affordable cost using solely commodity components. Different implementations of message-passing libraries and system softwares (including Operating Systems) are installed in such cluster and multi-cluster computing systems. In order to guarantee correct execution of message-passing parallel applications in a computing environment other than that originally the parallel application was developed, review of the application code is needed. In this paper, a hybrid communication interfacing strategy is proposed, to execute a parallel application in a group of computing nodes belonging to different clusters or multi-clusters (computing systems may be running different operating systems and MPI implementations), interconnected with public or private IP addresses, and responding interchangeably to user execution requests. Experimental results demonstrate the feasibility of this proposed strategy and its effectiveness, through the execution of benchmarking parallel applications.     

A Refinement Calculus for Shared-Variable Parallel and Distributed Programming

Parallel computers have not yet had the expected impact on mainstream computing. Parallelism adds a level of complexity to the programming task that makes it very error-prone. Moreover, a large variety of very different parallel architectures exists. Porting an implementation from one machine to another may require substantial changes. This paper addresses some of these problems by developing a formal basis for the design of parallel programs in the form of a refinement calculus. The calculus allows the stepwise formal derivation of an abstract, low-level implementation from a trusted, high-level specification. The calculus thus helps structuring and documenting the development process. Portability is increased, because the introduction of a machine-dependent feature can be located in the refinement tree. Development efforts above this point in the tree are independent of that feature and are thus reusable. Moreover, the discovery of new, possibly more efficient solutions is facilitated. Last but not least, programs are correct by construction, which obviates the need for difficult debugging. Our programming/specification notation supports fair parallelism, shared-variable and message-passing concurrency, local variables and channels. The calculus rests on a compositional trace semantics that treats shared-variable and message-passing concurrency uniformly. The refinement relation combines a context-sensitive notion of trace inclusion and assumption-commitment reasoning to achieve compositionality. The calculus straddles both concurrency paradigms, that is, a shared-variable program can be refined into a distributed, message-passing program and vice versa. Received July 2001 / Accepted in revised form May 2002     

基于SMP集群系统的并行编程模式研究与分析

并行计算技术是计算机技术发展的重要方向之一,SMP与集群是当前主流的并行体系结构。当前并行程序设计方法主要采用基于消息传递模型的MPI和基于共享存储模型的OpenMP,两种编程模式各有特点和适用范围。对SMP集群以及MPI和OpenMP的特点进行了分析,介绍了在SMP集群系统中利用MPI和OpenMP混合编程的可行性方法。     

Testing Moderately Parallel Environments for an Ocean Modeling Application

Due to the high costs of accessing massively parallel and vector environments, as well as the overworking of high-performance computers, there is now a need for a different approach to parallel computing. The feasibility of ocean modeling in a moderately parallel environment is tested using a 2-D (vertically-integrated) ocean circulation model. The parallel algorithm is based on the Glenda message-passing software and follows the master-worker paradigm. It is evaluated on both internal and external communication environments. The numerical experiments show that the internal communication environment is only slightly more efficient than the external communication environment. This is due to a combination of shared memory problems in the internal communication environment and to inefficiencies in the message-passing software. The tests also demonstrate how efficiency depends on the domain sub-divisions. Most importantly, they show that both environments effectively outperform their sequential counterparts, reducing the program elapsed time, and offering quicker access to the model outputs. The parallel version provided a time-saving alternative to the sequential version of the same model on both internal and external communication platforms. This research supports the conclusion that both environments are a viable alternative to single-CPU machines and that moderately parallel environments are feasible computer platforms for ocean modeling applications.     

From Design Patterns to Parallel Architectural Skeletons

The concept of design patterns has been extensively studied and applied in the context of object-oriented software design. Similar ideas are being explored in other areas of computing as well. Over the past several years, researchers have been experimenting with the feasibility of employing design-patterns related concepts in the parallel computing domain. In the past, several pattern-based systems have been developed with the intention to facilitate faster parallel application development through the use of preimplemented and reusable components that are based on frequently used parallel computing design patterns. However, most of these systems face several serious limitations such as limited flexibility, zero extensibility, and the ad hoc nature of their components. Lack of flexibility in a parallel programming system limits a programmer to using only the high-level components provided by the system. Lack of extensibility here refers to the fact that most of the existing pattern-based parallel programming systems come with a set of prebuilt patterns integrated into the system. However, the system provides no obvious way of increasing the repertoire of patterns when need arises. Also, most of these systems do not offer any generic view of a parallel computing pattern, a fact which may be at the root of several of their shortcomings. This research proposes a generic (i.e., pattern- and application-independent) model for realizing and using parallel design patterns. The term “parallel architectural skeleton” is used to represent the set of generic attributes associated with a pattern. The Parallel Architectural Skeleton Model (PASM) is based on the message-passing paradigm, which makes it suitable for a LAN of workstations and PCs. The model is flexible as it allows the intermixing of high-level patterns with low-level message-passing primitives. An object-oriented and library-based implementation of the model has been completed using C++and MPI, without necessitating any language extension. The generic model and the library-based implementation allow new patterns to be defined and included into the system. The skeleton-library serves as a framework for the systematic, hierarchical development of network-oriented parallel applications.     

一种可靠的移动Agent组通信系统

为满足大规模计算任务的需求,设计一种移动Agent组通信系统。提出移动Agent组通信系统的模型,在此基础上提出移动Agent可靠消息传输协议和组管理协议,消息传输协议保证了消息传递可靠性,即使Agent正在移动,也能保证消息最终可以到达目标,组管理协议保证了组成员管理的灵活性、可扩展性,保证了故障检测完整性、精确性和网络负载低。