有效的数组私有化方法:相关-覆盖方法

数组私有化是并行化编译中的重要技术,该方针对现有数级私有化方法的不足,分析了数组私有化的本质,提出了一个数组私有方法：相关－覆盖方法。它将相关性分析技术和数据覆盖技术有机地结合在一起,具有了执行效率高、处理能力强、独立于数据表示的特点。     

基于压缩后缀数组技术的搜索引擎

目前,搜索引擎的核心模块(索引器)均采用倒排文件结构,对短语查询的准确率较低。该文引入后缀数组技术进行全文索引,为克服全文索引时占用空间大的缺点,研究了压缩后缀数组技术,把后缀数组索引的大小压缩到了O(n)位,并给出应用压缩后缀数组索引的步骤和核心操作伪代码。对比实验表明,基于压缩后缀数组的索引比传统倒排文件索引的短语查准率提高了近20%。     

基于压缩后缀数组的搜索引擎技术

搜索引擎(Search Eng ine)技术是在网络数据成指数级增加的情况下出现的新技术。然而现在的搜索引擎在检索时都采用的是倒排文件,从后缀数据技术出发探讨了压缩后缀数组(Com pressed Su ffix A rray)技术在搜索引擎技术中的应用,从而大大提高了搜索引擎的性能。     

基于后缀数组的分词技术①

中文分词技术是机器翻译、分类、搜索引擎以及信息检索的基础,但是,互联网上不断出现的新词严重影响了分词的性能,为了提高新词的识别率,建立待分词内容的后缀数组,然后计算其公共前缀共同出现的次数,采用阈值对其进行过滤筛选出候选词语,实验结果表明,该方法在新词识别方面有一定的优势。     

基于多重数组的词典技术研究与实现

词典的查询速度直接影响到分词系统的处理速度,从而影响到整个系统的性能,基于多重数组的分词词典技术很好的解决了词典的查询速度问题。     

多核微机基于OpenMP的并行计算

随着四核微机走向市场和八十核处理器在实验室研制成功,多核正引领软件研发发生基础性变化。开发人员需要在代码中添加线程来利用系统所提供的多个内核,从而提升PC应用软件的功能和性能。文中探讨在多核微机上进行并行计算的实现技术。介绍了共享存储系统并行编程接口OpenMP的模型、指令和库函数,以及Intel C 编译器9.1和Microsoft Visual Studio 2005等对OpenMP的支持;着重探讨了二维离散快速傅里叶变换并行算法的设计、实现与优化技术;展望了高性能并行计算软构件库的开发前景。     

多核微机基于OpenMP的并行计算

随着四核微机走向市场和八十核处理器在实验室研制成功，多核正引领软件研发发生基础性变化。开发人员需要在代码中添加线程来利用系统所提供的多个内核，从而提升PC应用软件的功能和性能。文中探讨在多核微机上进行并行计算的实现技术。介绍了共享存储系统并行编程接口OpenMP的模型、指令和库函数，以及Intel C＋＋编译器9．1和Microsoft Visual Studio 2005等对OpenMP的支持；着重探讨了二维离散快速傅里叶变换并行算法的设计、实现与优化技术；展望了高性能并行计算软构件库的开发前景。     

基于类的VB.NET控件数组设计

为了解决VB.NET中控件不能象VB6.0使用数组的问题,提出了基于类的控件数组解决方案,并就类控件数组的设计原理和实现方法进行了介绍。     

基于密文数据库中数组检索的研究

通过比较集中索引以及分散索引,提出一种更为快捷的数组索引的密文查询方法,并较详细阐述了三者在时间、空间、安全性等方面的特点,从而体现出这种索引数组特有的优越性.     

基于数组的增量式属性约简研究*

为了在动态变化的决策表中,快速方便地获得新的属性约简,利用数组元素对差别矩阵中的属性组合进行计数,提出一种基于数组的增量式属性约简更新算法。当决策表动态变化时,根据数组元素的取值变化,获得差别矩阵中增加和减少的元素,依据这些元素更新原属性约简,快速得到新的最小属性约简。理论分析及实例验证了提出的算法是有效的。     

Supporting OpenMP on Cell

The Cell processor is a heterogeneous multi-core processor with one power processing engine (PPE) core and eight synergistic processing engine (SPE) cores. There is a significant amount of ongoing research in programming models and tools that attempts to make it easy to exploit the computation power of the Cell architecture. In our work, we explore supporting OpenMP on the Cell processor. It is attractive to support OpenMP because programmers can continue using their familiar programming model, and existing code can be re-used. We base our work on IBM’s XL compiler, and developed new components in the XL compiler and a new runtime library. Three major issues are addressed: (1) synchronization support on heterogeneous cores; (2) code generation targeting the different instruction sets; (3) data transfers and implement the OpenMP memory model. We present experimental results for some SPEC OMP 2001 and NAS benchmarks to demonstrate the effectiveness of this approach. A visualization tool based on Paraver is also used to provide some insights into actual thread and synchronization behaviors.     

Performance and scalability analysis of image processing applications on the IBM Cell BE simulator

The IBM Cell Broadband Engine （BE） simulator simulates parallel execution of programs on a state-of-the-art 9-core Cell processor model. In this paper, we report our experience with implementing, simulation, and analyzing the performance of image processing applications on the IBM Cell Broadband Engine Simulator measured on the IBM Cell We report the performance simulator for PPE-only and embedded applications, and with various input data file sizes or numbers of SPEs enabled. The simulator results indicate that Cell BE processor can outperform modern single-core RISC processors in orders of magnitude on SIMD compute intensive applications such as edge detection. We also explore different features and development processes available on the simulator. Different techniques for obtaining accurate results （close to real hardware result） are also explored.     

浅谈IBM pSeries平台的灾难备份

文章介绍了灾难备份的重要性，并描述了IBM HAGEO（High Availlability Geographics Cluster)灾难备份解决方案GeoRM(Geographics Remote Mirroring)远程数据镜像解决方案。     

Optimizing OpenMP Programs on Software Distributed Shared Memory Systems

This paper describes compiler techniques that can translate standard OpenMP applications into code for distributed computer systems. OpenMP has emerged as an important model and language extension for shared-memory parallel programming. However, despite OpenMP's success on these platforms, it is not currently being used on distributed system. The long-term goal of our project is to quantify the degree to which such a use is possible and develop supporting compiler techniques. Our present compiler techniques translate OpenMP programs into a form suitable for execution on a Software DSM system. We have implemented a compiler that performs this basic translation, and we have studied a number of hand optimizations that improve the baseline performance. Our approach complements related efforts that have proposed language extensions for efficient execution of OpenMP programs on distributed systems. Our results show that, while kernel benchmarks can show high efficiency of OpenMP programs on distributed systems, full applications need careful consideration of shared data access patterns. A naive translation (similar to OpenMP compilers for SMPs) leads to acceptable performance in very few applications only. However, additional optimizations, including access privatization, selective touch, and dynamic scheduling, resulting in 31% average improvement on our benchmarks.     

MPI+OpenMP混合并行编程模型应用研究

多处理器结点集群在高性能计算市场上日趋流行,如何在多处理器上编写出高效的并行代码成为研究的热点。MPI+OpenMP为多处理器结点集群提供了一种有效的并行策略,结点内部共享内存空间编程模式适合 OpenMP并行,消息传递模型MPI被用在集群的结点与结点之间,这样就实现了并行的层次结构化。     

Study of OpenMP applications on the InfiniBand-based software distributed shared-memory system

For the past decades computer engineers have focused on building high-performance and large-scale computer systems with low-cost. One of the examples is a distributed-memory computer system like a cluster, where fast processing nodes to use commodity processors are connected through a high speed network. But it is not easy to develop applications on this system, because a programmer must consider all data and control dependences between processes and program them explicitly. For alleviating this problem the distributed virtual shared-memory (DVSM) system has been proposed. It is well known that the performance of the DVSM system highly depends on the network’s performance and programming semantics, and currently its performance is very limited on a conventional network. Recently many advanced hardware-based interconnection technologies have been introduced, and one of them is the InfiniBand Architecture (IBA) which supports shared-memory programming semantics by means of remote direct-memory access (RDMA) and atomic operations. In this paper, we present the implementation of our InfiniBand-based DVSM system and analyze the performance of SPEC OMP benchmarks in detail by comparing with the DVSM based on the traditional network architecture and the hardware shared-memory multiprocessor (SMP) system. As experiment result, we show that our DVSM system to use full features of the IBA can improve the performance significantly over the IPoIB-based traditional system on the IBA, and furthermore the performance of one application on the IBA-based DVSM system is better than on the hardware SMP.     

机群OpenMP系统的设计与实现

OpenMP以其易用性和支持增量并行的特点成为共享存储体系结构的编程标准．目前机群系统已成为高性能计算的主流平台,研究机群OpenMP系统对推进并行应用的开发和普及非常有意义．该文作者以软件DSM系统JIAJIA作为OpenMP的运行时系统,结合一个前端编译器OMP2JIA,在机群系统上实现了OpenMP／JIAJIA计算环境,同时在提高性能方面根据机群系统特点扩展了OpenMP制导,优化了后端运行时库。通过11个OpenMP应用,作者比较了该计算环境和一个支持OpenMP的硬件cc-NUMA系统(SGI 2100)的性能．结果表明,作者的机群OpenMP系统的7机平均加速比为4．62;SGI 2100系统为4．55,二者性能相当．     

基于OpenMP的动态模式识别并行计算

考虑到实现确定学习理论中的动态模式识别过程耗时过多,提出一种适用于识别过程计算的多核并行技术。以压气机Mansoux模型为研究背景,首先对其模式获取和识别的过程进行简单描述,其次,在四核PC的硬件平台上,使用OpenMP编程,实现了对动态模式识别的并行计算。通过设置不同的线程数,讨论了几个影响并行程序性能的重要因素。结果表明,要综合考虑各种因素的影响才能设计出高效的并行识别程序。     

基于混合并行的Kriging插值算法研究

普通Kriging方法是进行空间降水插值的一种有效方法。然而一方面由于海量数据插值计算量大,另一方面该算法的时间复杂度大,为减少空间降水插值的计算时间,采用OpenMP和MPI混合并行技术,实现Kriging并行算法。在Windows操作系统上搭建并行计算环境,实验数据表明,该并行算法能有效地节省计算时间。