用VxWorks的信号量机制实现任务同步

为了保证诸任务对临界critical资源resource的互斥访问，VxWorks提供了任务同步机制。二进制信号量是VxWorks系统中实现任务同步的一种重要手段，它保证了任务在并发时结果的一致性。简要介绍二进制信号量，阐述用二进制信号量解决任务互斥和同步的方法，并给出二进制信号量应用在某数据采集系统中的程序框架。某数据采集系统中有效地利用了VxWorks的信号量机制，实现了8个接收通道的数据采集、数据存储以及数据查询等任务对缓冲区的共享。     

Software transactional memories: an approach for multicore programming

The recent advance of multicore architectures and the deployment of multiprocessors as the mainstream computing platforms have given rise to a new concurrent programming impetus. Software transactional memories (STM) are one of the most promising approaches to take up this challenge. The aim of a STM system is to discharge the application programmer from the management of synchronization when he/she has to write multiprocess programs. His/her task is to decompose his/her program into a set of sequential tasks that access shared objects, and to decompose each task in atomic units of computation. The management of the required synchronization is ensured by the associated STM system. This paper presents two existing STM systems, and a new one based on time-window mechanism. The paper, which focuses mainly on STM principles, has an introductory and survey flavor.     

测控设备控制计算机实时应用软件的设计与实现

本文研究了模型化和设计测控设备控制计算机实时应用软件时需要解决的几个关键问题：实时任务划分、实时调度算法的设计和选择以及实时任务驱动和同步方法的设计等。     

Enhancing self-scheduling algorithms via synchronization and weighting

Existing dynamic self-scheduling algorithms, used to schedule independent tasks on heterogeneous clusters, cannot handle tasks with dependencies because they lack the support for internode communication. To compensate for this deficiency we introduce a synchronization mechanism that provides inter-processor communication, thus, enabling self-scheduling algorithms to handle efficiently nested loops with dependencies. We also present a weighting mechanism that significantly improves the performance of dynamic self-scheduling algorithms. These algorithms divide the total number of tasks into chunks and assign them to processors. The weighting mechanism adapts the chunk sizes to the computing power and current run-queue state of the processors. The synchronization and weighting mechanisms are orthogonal, in the sense that they can simultaneously be applied to loops with dependencies. Thus, they broaden the application spectrum of dynamic self-scheduling algorithms and improve their performance. Extensive testing confirms the efficiency of the synchronization and weighting mechanisms and the significant improvement of the synchronized–weighted versions of the algorithms over the synchronized-only versions.     

车载ATP安全技术平台同步机制

车载ATP安全技术平台是基于三模冗余的三取二容错计算机。针对3套计算机系统的同步问题,基于采用公共外时钟同步与时钟漂移变化率有界结合的模型对本地时钟进行偏移和漂移补偿,实现系统本地时钟的同步。在此基础上,软件采用时序控制的方式实现三模系统的任务同步。多次实验结果表明,该同步机制能满足三取二容错计算机在同步技术上的要求。     

Modeling shared resources with generalized synchronization within aPetri net bottom-up approach

This paper proposes a simple and effective way to represent shared resources in manufacturing systems within a Petri net model previously developed. Such a model relies on the bottom-up and modular approach to synthesis and analysis. The designer may define elementary tasks and then connect them with one another with three kinds of connections: self-loops, inhibitor arcs and simple synchronizations. A theoretical framework has been established for the analysis of liveness and reversibility of such models. The generalized synchronization, here formalized, represents an extension of the simple synchronization, allowing the merging of suitable subnets among elementary tasks. It is proved that under suitable, but not restrictive, hypotheses the generalized synchronization may be substituted for a simple one, thus being compatible with all the developed theoretical body.     

系统集成中的时钟同步技术

总结了目前分布环境下时间同步的各种策略、技术、原理和方法 ,着重介绍了一种利用 GPS接收设备作为时间源、About Time共享软件作为同步工具的经济、可靠、准确的系统时钟同步模型     

Analysis of processor allocation in multiprogrammed,distributed-memory parallel processing systems

A main objective of scheduling independent jobs composed of multiple sequential tasks in shared-memory and distributed-memory multiprocessor computer systems is the assignment of these tasks to processors in a manner that ensures efficient operation of the system. Achieving this objective requires the analysis of a fundamental tradeoff between maximizing parallel execution, suggesting that the tasks of a job be spread across all system processors, and minimizing synchronization and communication overheads, suggesting that the job's tasks be executed on a single processor. The authors consider a class of scheduling policies that represent the essential aspects of this processor allocation tradeoff, and model the system as a distributed fork-join queueing system. They derive an approximation for the expected job response time, which includes the important effects of various parallel processing overheads (such as task synchronization and communication) induced by the processor allocation policy     

Effective Implementation of a Parallel Language on a Multiprocessor

A new multiprocessor execution environment integrates semantics of parallel control with mechanisms for synchronization of concurrent tasks.     

异步通讯模式下的精确时间同步与IEEE1588

从异步通讯模式下的同步时钟的最基本原理出发,通过阐述IEEE1588的基本设计思想,具体分析了在协议具体实现过程中影响同步时钟精度的主要因素。     

利用JAVA多线程并发机制解决生产者—消费者问题

本文分析并描述了JAVA多线程并发过程中的同步机制及消息通信机制的基本原理,探讨如何运用多线程同步机制和消息互通机制切实解决生产者和消费者之间的问题。     

On tasks synchronization with the MMS protocol

The MMS protocol is a powerful tool for communication as well as for synchronization between manufacturing equipment such as robots, programmable logic controllers, etc. This paper shows how the MMS services can be used to handle tasks synchronization in a distributed environment. The MMS weaknesses regarding temporal aspects and possible directions to alleviate these weaknesses are also presented.     

优化并行图重写计算粒度的编译时部分调度策略

并行图重写计算的有效实现需要压缩重写任务的频繁生成、切换和同步开销.为此本文提出了一种编译时重写粒度优化技术——编译时部分调度.其核心思想是基于对重写结点的全序性质和执行语义的分析,编译时构造 保持原有执行语义的粗粒度顺序重写体。在本文定义的形式框架下,我们建立了编译时部分调度的安全条件,并给出了严格的证明.实验研究结果表明编译时部分调度能有效地增大重写粒度,重写任务数压缩了30—60％,并且计算的安全性得到了保证.     

自组织网络时钟同步研究综述

时钟同步是自组织网络研究的关键技术之一,是多种网络功能实现的基础。对自组织网络时钟同步方法进行综述,依据同步原理对现有自组织网络时钟同步方法进行分类,并从可扩展性、网络开销、同步精度等方面对不同类别中具有代表性的时钟同步方法进行比较和分析。同时,根据无线传感器网络(Wireless Sensor Network,WSN)和自组织网络在时钟同步方面的相似性,列举出一些自组织网络可借鉴的WSN时钟同步方法。最后根据自组织网络时钟同步技术面临的新问题以及现有方法中的不足,展望自组织网络时钟同步技术的进一步研究方向。     

基于数据交换与同步的作业调度方案

多机作业调度问题是一个经典的NP难问题,在应用中由于实际需要,会出现各种约束和变形,调度问题的研究成果决定着系统的性能.DataTurbo是作者参与的一个用于解决分布式数据迁移、集成和融合的平台,该平台承担着大数据量的分布式传输任务.在DataTurbo平台基础上,提出一种适用于数据交换与同步的分布式作业调度方案,并构建一个灵活的分布式调度算法框架,解决相关的调度问题.该调度方案是一种在线的、可并发的、作业可分解的多机调度方案.仿真实验结果显示,该调度方案在任务负载大、调度点稀疏情况下优势明显,能适用于数据交换同步作业,可作为数据交换与同步作业的动态调度方案,并为相关启发式算法建立基础模型.     

A framework for argument-based task synchronization with automatic detection of dependencies

Synchronization in parallel applications can be achieved either implicitly or explicitly. Implicit synchronization is typical of programming environments that provide predefined, and often simple, patterns of parallelism such as data-parallel libraries and languages and skeletal operations. Nevertheless, more flexible approaches that allow to express arbitrary task-level parallel computations without a predefined structure request in turn that the user explicitly specifies the synchronization needed among the parallel tasks.     

IEEE 1588精确时间同步协议浅析

本文研究了IEEE 1588精确时间同步协议的基本原理、核心算法和技术特点。该协议主要解决传统网络时间同步技术精度不高和安全性差等问题。相比已有的基于网络时间协议(NTP)或GPS的时间同步技术,基于IEEE 1588协议的时间同步技术具有很高的精确性、安全性和可控性,能够较好地满足通信网同步、电力系统、工业控制、高精密测量等应用领域的时间同步要求。     

IEEE 1588精密时钟同步协议2.0版本浅析

在分布式测控系统中,各分布式设备、独立的智能传感器、作动器与系统之间的时钟同步是系统测控数据有效性的关键。IEEE 1588精密时钟同步协议有效地解决了分布式测控系统时间同步问题,也是新测试系统总线标准LXI的核心技术之一。首先介绍了IEEE 1588时钟同步的基本原理,之后主要针对最新发布的IEEE 1588 2.0版本所采用的新技术、新方法进行了分析,为进一步研究打下基础。     

基于WEB服务的分布式异构数据同步设计

分析分布式数据同步的方式,解决基于互联网WEB端口的异构数据同步问题,结合SOA架构的特征提出一种分布式异构数据同步模型WLDSS（Web-levelDataSynchronizationSystem）,给出了该模型的设计原理、关键策略,通过分布式太阳能热水系统的控制系统数据同步的应用验证了WLDSS模型稳定性。