一种挖掘多核处理器存储级并行的算法

多核处理器中,各个处理器核之间可以并发地进行外部存储访问,提供不同于单处理器的存储级并行(memory level parallelism)能力.不规则应用中的循环,传统的并行方法难以识别其并行性,不能充分利用多核处理器存储级并行能力和并行计算能力.对基于软件开发多核处理器存储级并行进行了讨论,提出一种前瞻并行多线程算法LLSM(loop level speculative mssultithreading).LLSM对不规则应用中的循环进行并行化,在多核处理器上的测试数据表明:该算法能够有效地挖掘多核处理器的存储级并行能力和计算能力,同时指出多核环境下存储级并行计算公式需要考虑线程同步开销.     

多核并行技术在分子动力学模拟中的应用

为了充分利用多核处理器资源,研究了一种用于分子动力学模拟中的多核并行技术。在多核处理器上利用OpenMP技术实现多线程创建与同步、动态设置子线程的调度运行方式以及负载均衡以减少子线程执行等待时间。通过对不同分子体系结构下的动力学模型测试,得出在不同子线程下并行计算的时间,并且得到了良好的性能加速比。实验结果表明,采用OpenMP并行技术可有效地提高电荷求解过程在分子动力学模拟运算中的时间效率,以及多核计算机资源的利用率。     

时钟共享多线程处理器通信机制的设计与实现

多核多线程处理器~([1])是并行技术的一个发展方向,基于多核多线程处理器,提出了一种时钟共享多线程处理器。该处理器有近邻通信和线程间通信两种通信机制,近邻通信采用近邻共享FIFO来传递信息,线程间通信通过线程间共享存储来传递信息,这样可以提高处理器的资源利用率和并行执行能力。     

IA-64的并行架构及其寄存器文件

同时多线程能在同一时钟周期执行不同线程的指令,并且指令级并行和线程级并行。显式并行指令计算关注于编译器和硬件的相互协作。寄存器文件的设计在高性能处理器设计中十分重要,寄存器栈和寄存器栈引擎是提高其性能的重要手段。该文设计和实现一套并行环境,其中包括并行编译器OpenUH和基于IA-64的同时多线程体系结构EDSMT,实验表明,该并行架构适用于大多数并行应用,针对NAS的并行测试程序,该架构相对于SMTSIM平均有12.48%的性能提升。     

基于TBB任务调度器的N皇后多核并行算法

为了充分利用多核处理器资源,研究了Intel线程构建模块并行编程模式.基于任务调度器,建立了逻辑线程和物理线程最佳匹配和映射的面向任务编程模式.利用任务调度器,设计了N皇后问题在多核处理器的并行算法.该算法将任务自动地映射到多线程,减少消息传递和数据移动带来的额外开销,提高多核CPU的使用效率.并行算法的加速比接近核数,CPU使用效率超过90%,实验结果表明,该算法有效地提升了多核计算机资源的利用率.     

基于线程级的同时多线程处理器功耗评估

针对同时多线程处理器中每个线程的功耗评估问题,提出一种同时多线程基于线程级的功耗评估方法。该方法可使系统在运行过程中统计出各线程对各部件的详细功耗情况,方便地衡量在多线程运行时各线程所产生的功耗。为同时多线程处理器进行基于功耗已知的线程调度和取指策略研究提供了基础条件。实验结果表明,各线程的功耗之和与总功耗相等。     

一种基于IA-64的并行架构的研究

同时多线程（SMT）能在同一时钟周期执行不同线程的指令,同时开发了指令级并行（ILP）和线程级并行（TLP）。显式并行指令计算（EPIC）关注于编译器和硬件的相互协作。在本文中,我们设计和实现了一套并行环境,其中包括并行编译器OpenUH和基于IA-64的同时多线程体系结构EDSMT,并通过NAS并行测试程序作出了性能评测。     

基于EPIC的同时多线程处理器取指策略

EPIC硬件简单，同时多线程易于开发线程级并行，在EPIC上实现同时多线程可以结合二者的优点。取指策略对同时多线程处理器的性能有重要影响。该文介绍了几种有代表性的超标量同时多线程处理器取指策略，分析了这些策略在EPIC同时多线程处理器上的适用性，提出了一种新的适用于EPIC的取指策略SICOUNT。分析表明SICOUNT策略可以充分利用EPIC软硬件协同的优势，在选择取指线程时使用编译器所提供的停顿信息，能更精确地估计各个线程的流动速度，使取出指令的质量更高。     

多态并行处理器中的线程管理器设计

基于多态并行处理器提出了一种硬件线程管理器,支持MIMD模式8个线程管理操作和SIMD模式SC控制器统一管理两种工作模式,实现了线程级并行计算;可以监测各个线程的工作情况以及近邻通信寄存器和路由器的状态;能够在通信时停止、切换、启动线程,记录每个线程的工作状态,同时避免了因数据阻塞带来的等待问题,能够最大程度地提高单个处理器的执行效率。     

面向多核处理器的多实例并行BGP协议模型设计与实现

开发BGP的线程级并行可以满足不断膨胀的互联网应用对协议性能的迫切需求。本文提出了一种面向多核处理器的多实例并行BGP协议模型,它以邻居会话划分为基础,借助数据并行思想实现了不同邻居会话在多个线程上的并行处理。首先,通过分析BGP协议特点,我们给出了该模型的总体框架设计,然后在Quagga BGP的基础上完成了具体实现。在Intel Xeon四核服务器上的性能测试结果显示,多实例并行BGP协议较BGP协议的性能加速均值在2.73左右,并且能够有效利用多核处理器计算资源,为改善协议处理能力提供了更大的提升空间。     

Three-Link Mechanism as a Model of a Person on a Swing

Journal of Computer and Systems Sciences International - We model movements of a person swinging on a swing. We consider a flat three-link hinged mechanism as the main mechanical model of the...     

On a nonlinear problem of a sequential control with a parameter

The problem of evasion of a group of moving points from a nonlinear controlled object, whose goal is consecutively approach these points in a prescribed order, is analyzed. The movement of each point is defined uniquely by a scalar parameter chosen at the initial time instant. The controlled object minimizes a certain cost function, and the group of the points, acting cooperatively, maximize this cost function by choosing the parameters. Necessary optimality conditions for parameters are obtained. A model problem of an evasion of moving points from a vehicle is solved.     

Splitting a configuration in a simplex

This paper presents a new method of partition, named-splitting, of a point set ind-dimensional space. Given a pointG in ad-dimensional simplexT, T(G;i) is the subsimplex spanned by G and the ith facet ofT. LetS be a set ofn points inT, and let be a sequence of nonnegative integers ₁, ..., n_d+1 satisfying _i=1 ^d+1 ₁=n The-splitter of (T, S) is a pointG inT such thatT(G;i) contains at least _i points ofS in its closure for everyi=1, 2, ...,d + 1. The associated dissection is the re-splitting.The existence of a-splitting is shown for any (T, S) and, and two efficient algorithms for finding such a splitting are given. One runs inO(d²n logn + d³n) time, and the other runs inO(n) time if the dimensiond can be considered as a constant. Applications of re-splitting to mesh generation, polygonal-tour generation, and a combinatorial assignment problem are given.     

Combining a monad and a comonad

We give a systematic treatment of distributivity for a monad and a comonad as arises in giving category theoretic accounts of operational and denotational semantics, and in giving an intensional denotational semantics. We do this axiomatically, in terms of a monad and a comonad in a 2-category, giving accounts of the Eilenberg–Moore and Kleisli constructions. We analyse the eight possible relationships, deducing that two pairs are isomorphic, but that the other pairs are all distinct. We develop those 2-categorical definitions necessary to support this analysis.     

Not a castaway but a stowaway

A portable keyboard that's no larger than my phone, that's theiGo Stowaway.     

Building a sonar map in a specular environment using a singlemobile sensor

The physical properties of acoustic sensors are exploited to obtain information about the environment for sonar map building. A theoretical formulation for interpreting the sensor databases on the physical principles of acoustic propagation and reflection is presented. A characterization of the sonar scan that allows the differentiation of planes, corners, and edges in a specular environment is described. A single sensor mounted on an autonomous vehicle in a laboratory verifies the technique. The implications for sonar map building and the limitations of differentiating elements with one sensor are discussed     

Motion control of a rotor with a cavity with a viscous fluid

A formulation and solution procedure of optimal control problems for perturbed relative uniform motion of a body with a cavity filled with a viscous incompressible fluid are proposed. In this paper, the case with a cylinder is considered; however, this approach is basically true for the a cavity of an arbitrary form. The formula for the angular velocity of perturbed motion depending on an external perturbing element is devised. After that, we have a possibility to set different optimal control problems and apply the formalism elaborated in the optimal control theory. Two illustrated problems are given.