一种用于并行系统的非阻塞消息队列机制

并行线程之间的消息传递和同步机制与系统的并行性能密切相关。在并行系统中,人们期望不必要的同步尽可能少,以充分开发系统的并行性,提高系统的运行效率。非阻塞缓冲区机制(NBB)允许消息生产者和消费者在不使用同步机制的情况下实现消息传递。但是,NBB机制存在着消息缓冲区有限、在多生产者和/或多消费者情况下使用不便、有时甚至功能不能满足要求等问题。本文介绍的非阻塞队列机制(NBL)可看作是NBB的链表实现,但NBL可以有效地避免NBB的上述缺陷。本文描述了相关算法及其正确性证明。最后讨论了NBL机制的使用方法,并进行了有效性和性能评测。     

一种基于XML及SOAP的分布式工作流系统消息传递机制

为满足工作流系统在跨平台、分布式计算和可扩展性方面的需求,本文提出一种基于XML及SOAP的分布式工作流系统的混合模式消息传递机制.采用XML作为系统消息及数据交换的统一标准,提供MOM消息与SOAP消息间自动转换机制,捆绑HTTP协议传输SOAP消息,最终达到实现异构分布式工作流系统间通信的目的.     

Sybase整编消息队列

4月2日获悉:Sybase公司推出dbQ新型数据库消息排队系统,使Sybase成为全球首家在DBMS中集成消息排队机制的数据库厂商。 Sybase的dbQ可使基于Java、ActiveX或其他开发环境的开发人员,在快速应用软件开发中方便地进行数据库与消息排队。dbQ的队列传输管理器QTM能够确保消息在多种分布式平台之间的传递。QTM提供了灵活的消息传递选项,其中包括消息传递的优先级以及消息传递的确认。除了能够实现消息在多个dbQ服务器之间的传递外,dbQ还能够实现与IBM MQSeries间的信息共享。     

DotNet环境下分布式并发离散事件仿真建模与实现

DotNet环境对多线程技术提供了良好的支持,对于分布式离散事件,多线程技术能够以最少代价、最便捷的方式实现其并发活动的仿真。异步多线程仿真编程中的主要问题是线程的引入与控制、对各结点间的仿真时钟同步问题、线程间活动的同步与消息传递、临界变量的访问与保护机制等。从系统实现角度对这些问题进行分析是建模的必要条件件。本文进一步讨论了各结点间通过消息交互的加工过程,最后以控制台方式将分布式离散事件仿真中的主要关键活动编程实现。通过对仿真实现全过程的讨论可以看出,多线程技术能够有效地实现分布式并发离散事件的仿真。     

用DCOM对基于多Agent的专家系统进行组件化设计

用面向对象的方法来构造一个基于多Agent的专家系统,在分布式环境下对Agent进行基于DCOM组件化设计,并根据多Agent系统的协作需要,确定了合适的组件线程模型和异步消息传递机制。     

一种分布式SCADA消息中间件设计方案测控技术与仪器仪表

随着分布式SCADA系统在铁路牵引供电应用的不断推广,SCADA系统节点之间以及与其他异构系统之间进行消息数据传递面临着效率降低、接口不统一等问题。针对此问题,提出一种基于发布/订阅模式的分布式SCADA消息中间件的设计方案,该方案使用了N-Tree结构将系统消息进行逻辑区域划分,设计了一套完善的消息传递与反馈处理机制,方案中利用Quorum-Based改进型算法确保了分布式节点的消息一致性。实践及仿真实验证明,本方案提高了SCADA系统的消息传递效率,降低了分布式系统的运行负载和通信开销。     

μC/OS-Ⅱ实现实时消息传递

在众多的嵌入式实时操作系统中,μC/OS-Ⅱ因简单易学、源码清晰易读、结构协调、注解详尽,是嵌入式操作系统最佳的选择.设计一个消息传递系统,该系统实现的3个发送任务不断向消息队列发送消息,以及一个接受任务实时从消息队列接受消息.     

多线程中实现MFC成员函数的调用

分析了MFC成员函数在分别使用指针和句柄作为参数开启线程时遇到的不同问题,提出了使用消息传递机制,在子线程中发送消息到主线程,通过消息处理函数,实现对MPC类成员函数的调用,并通过一个具体的实例详细阐述了实现的方法。     

在MSM32中开发多线程程序

本文介绍了在MASM32环境下,进程、线程的操作方法,重点介绍了多线程程序的开发思路,以及三种线程间的通讯机制——使用全局变量、使用Windows消息传递机制和使用事件对象,以实现不同线程间的协同工作。     

在MASM32中开发多线程程序

本文介绍了在MASM32环境下,进程、线程的操作方法,重点介绍了多线程程序的开发思路,以及三种线程间的通讯机制——使用全局变量、使用Windows消息传递机制和使用事件对象．以实现不同线程间的协同工作。     

面向并行图像处理的实时分布式操作系统的设计与实现

针对多片TMS320C64 DSP构成的多计算机体系结构的实时图像识别系统，设计并实现了面向并行图像处理的实时分布式操作系统PIPORTDOS（Parallel image processing-oriented real-time distributed operating system）．PIPORTDOS基于微内核体系结构，包括硬件抽象层、系统核心层、分布式消息通信机制和系统服务层四个层次．其多任务内核实现了基于优先级的抢先式调度、任务闻的同步和通信原语、实时的中断处理以及面向应用的缓存管理机制．为了实现对分布式并行图像处理的支持，PIPORTDOS采用了基于消息传递（Message Passing）的方式，并在实现中充分考虑了上层图像处理算法的应用需求以及DSP的硬件功能．相关性能指标表明，本文设计实现的PIPORTDOS完全可以满足系统的强实时性要求．在功能上也能适应算法对不同并行结构的需求．     

Customized Message Passing

Replacing traditional operating systems communication implementations with customized implementations increases the performance of parallel and distributed applications. This paper describes the design and implementation of customizable message passing systems. The customized message passing systems are generated using application-specific information such as the profile of an application's communication pattern. FFT, Simplex, and Cholesky are used as example parallel applications. The message passing system has also been customized for different types of distributed system services including a distributed scheduling facility. The customized message passing system likewise improves the performance of these facilities and enhances their scalability. As a practical concern, as there are a large number of possible optimizations, object-oriented frameworks are employed to organize the implementations and to facilitate the choice of optimizations.     

Comparing shared and distributed memory computers

There are two distinct types of MIMD (Multiple Instruction, Multiple Data) computers: the shared memory machine, e.g. Butterfly, and the distributed memory machine, e.g. Hypercubes, Transputer arrays. Typically these utilize different programming models: the shared memory machine has monitors, semaphores and fetch-and-add; whereas the distributed memory machine uses message passing. Moreover there are two popular types of operating systems: a multi-tasking, asynchronous operating system and a crystalline, loosely synchronous operating system.

In this paper I firstly describe the Butterfly, Hypercube and Transputer array MIMD computers, and review monitors, semaphores, fetch-and-add and message passing; then I explain the two types of operating systems and give examples of how they are implemented on these MIMD computers. Next I discuss the advantages and disadvantages of shared memory machines with monitors, semaphores and fetch-and-add, compared to distributed memory machines using message passing, answering questions such as “is one model ‘easier’ to program than the other?” and “which is ‘more efficient‘?”. One may think that a shared memory machine with monitors, semaphores and fetch-and-add is simpler to program and runs faster than a distributed memory machine using message passing but we shall see that this is not necessarily the case. Finally I briefly discuss which type of operating system to use and on which type of computer. This of course depends on the algorithm one wishes to compute.     

Dawning-1000 PROOS Distributed Operating System

PROOS is a distributed operating system running on the computing nodes of massively parallel processing computer Dawning-1000.It is an efficient and easily extendible micro kernel operating system.It supports the Intel NX message passing interface for communication.     

An efficient scheduler of RTOS for multi/many-core system

Recently there is a trend to broaden the usage of lower-power embedded media processor core to build the future high-end computing machine or the supercomputer. However the embedded solution also faces the operating system (OS) design challenge which the thread invoking overhead is higher for fine-grained scientific workload, the message passing among threads is not managed efficiently enough and the OS does not provide convenient enough service for parallel programming. This paper presents a scheduler of master-slave real-time operating system (RTOS) to manage the thread running for the distributed multi/many-core system without shared memories. The proposed scheduler exploits the data-driven feature of scientific workloads to reduce the thread invoking overhead. And it also defines two protocols: (1) one is between the RTOS and application program, which is used to reduce the burden of parallel programming for the programmer; (2) another one is between the RTOS and networks-on-chip, which is used to manage the message passing among threads efficiently. The experimental results show that the proposed scheduler can manage the thread running with lower overhead and less storage requirement, thereby, improving the multi/many-core system performance.     

Modelling and performance analysis of inter-processor messaging in distributed systems

This paper addresses some performance modelling issues arising from the inter-processor messaging requirements of distributed real-time processing systems. We consider two basic classes of message transfer protocols, namely clocked schemes where message transfer is initiated as a periodic timed task, and event-driven schemes where the transfer mechanism is triggered by the messaging requests themselves. The aim is to maximize system efficiency by passing messages in batches. It is shown how the classes of protocols may be modelled by a two-stage queueing systems, which is analysed using the theory of imbedded Markov chains and semi-Markov processes. The results are used to show how the important performance measures are derived, and how the protocol parameters should be chosen to optimize the overall message system performance. The methods are illustrated by numerical examples.     

基于消息帧的动态时间设计

分布式实时系统应用日益增长,网络处理实时消息的能力变得越来越重要。通过对消息帧的时间特性的研究,提出了一种基于消息帧的动态时间设置的方法,使消息帧的优先级可以动态更改,提高消息帧传送的实时性,使得CAN总线更适应于实时应用。     

一种基于分布式结构的雷达系统仿真引擎机制研究*

随着系统规模的不断扩大,系统复杂度大大提高,采用单一的仿真程序已不能满足大规模复杂系统仿真的需求,采用分布式结构进行雷达系统仿真逐渐成为一种解决复杂系统仿真的主要方法。仿真引擎机制的研究是雷达仿真系统设计的关键,有利于深化和提升雷达仿真的效率。阐述了雷达仿真系统模型,采用分布式结构,提出了基于消息服务中心MSC和运行监控中心SC两层控制结构的仿真引擎机制,将用户接口服务与消息传递服务分离开来,增强了雷达仿真软件的灵活性和易操作性。在这种机制下,进一步提出了消息传递算法MPA并进行了系统性能测试和验证,仿真实验结果表明,MPA算法可以快速、可靠地实现雷达系统内部各执程体间的互连互通,准确地完成雷达仿真过程的控制与监视。     

面向分布式控制系统的实时SOA研究与应用

SOA(Service Oriented Architecture)已广泛应用于传统信息系统领域。如何将sOA思想应用于社会上广泛存在的分布式控制系统的构建,是服务计算领域的一个新的研究课题。针对分布式控制系统的特点及面向服务的思想,提出一种可有效解决消息可靠性传输、服务实时性处理的层次化实时SOA模型,给出各层次模型的详细思路与实现机制。基于该模型,设计并实现了电力配网自动化系统的底层多网络冗余实时消息总线原型系统,并给出了相关结 论。     

基于请求应答方式消息传递机制有色Petri网模型

分布式系统的对等模型中,各个节点从功能上看是对等关系,相互之间进行消息的请求和响应。讨论了一种将广播请求和点到点应答两种通信方式相结合的消息传递机制FMPRR(Fast Message Passing based on Request Response mode)的实现,这种机制采用wormhole寻径流控策略。用有色Petri网来形式化描述和分析FMPRR,通过模型状态空间分析结果,对FMPRR消息传递机制进行验证。