Signals,timers, and continuations for multithreaded user‐level protocols

Precise timing and asynchronous I/O are appealing features for many applications. Unix kernels provide such features on a per‐process basis, using signals to communicate asynchronous events to applications. Per‐process signals and timers are grossly inadequate for complex multithreaded applications that require per‐thread signals and timers that operate at finer granularity. To respond to this need, we present a scheme that integrates asynchronous (Unix) signals with user‐level threads, using the ARIADNE system as a platform. This is done with a view towards support for portable, multithreaded, and multiprotocol distributed applications, namely the CLAM (connectionless, lightweight, and multiway) communications library. In the same context, we propose the use of continuations as an efficient mechanism for reducing thread context‐switching and busy‐wait overheads in multithreaded protocols. Our proposal for integrating timers and signal‐handling mechanisms not only solves problems related to race conditions, but also offers an efficient and flexible interface for timing and signalling threads. Copyright © 2006 John Wiley & Sons, Ltd.     

An E?cient and Flexible Deterministic Framework for Multithreaded Programs

Determinism is very useful to multithreaded programs in debugging, testing, etc. Many deterministic ap-proaches have been proposed, such as deterministic multithreading (DMT) and deterministic replay. ...     

基于GPRS和嵌入式Linux的远程图像监控系统

阐述了一种基于GPRs和嵌入式Linux的远程图像监控系统设计和实现方法。该系统主要由嵌入式视频采集终端和监控中心服务器组成。其中,嵌入式视频采集终端主要由摄像头视频采集模块、ARM模块、SIM900模块组成,监控中心服务器可实时监控远程终端的图像。系统软件采用嵌入式Linux,可编程实现图像数据采集、压缩和GPRs模块的网络连接与传输。     

The Impact of Speculative Execution on SMT Processors

By executing two or more threads concurrently, Simultaneous MultiThreading (SMT) architectures are able to exploit both Instruction-Level Parallelism (ILP) and Thread-Level Parallelism (TLP) from the increased number of in-flight instructions that are fetched from multiple threads. However, due to incorrect control speculations, a significant number of these in-flight instructions are discarded from the pipelines of SMT processors (which is a direct consequence of these pipelines getting wider and deeper). Although increasing the accuracy of branch predictors may reduce the number of instructions so discarded from the pipelines, the prediction accuracy cannot be easily scaled up since aggressive branch prediction schemes strongly depend on the particular predictability inherently to the application programs. In this paper, we present an efficient thread scheduling mechanism for SMT processors, called SAFE-T (Speculation-Aware Front-End Throttling): it is easy to implement and allows an SMT processor to selectively perform speculative execution of threads according to the confidence level on branch predictions, hence preventing wrong-path instructions from being fetched. SAFE-T provides an average reduction of 57.9% in the number of discarded instructions and improves the instructions per cycle (IPC) performance by 14.7% on average over the ICOUNT policy across the multi-programmed workloads we simulate. This paper is an extended version of the paper, “Speculation Control for Simultaneous Multithreading,” which appeared in the Proceedings of the 18th International Parallel and Distributed Processing Symposium, Santa Fe, New Mexico, April 2004.     

合同战术训练评估系统体系结构

在介绍合同战术训练评估需求分析、系统总体结构的基础上,研究了其中的演习结果评估子系统的框架和层次结构,横向上将其分为主框架、行动评估模块、算法插件3个部分,纵向上把它分为数据采集、数据处理、成绩报告3层,从而有效地降低了系统各组成部分间的耦合程度,并使系统能综合运用多样化的数据采集手段以及效能分析方法,具有一定的参考价值。     

Sama机制在多线程方式下的消息传输

Sama是Hojjat Jafarpour,Nasser Yazdani,Navid Bazzaz-zadeh提出的在分布式系统中实现移动Agent组通信的机制,该机制很好的解决了移动Agent的组间通信问题。该文基于这一个通信机制,对其做了相关该进,给出了多线程下组间通信的算法,并举例说明了该算法的执行过程。     

基于VC++ 6.0的多串口通信方法

介绍了实现多串口通信的基本方法,采用VC 6.0并结合定时器和多线程技术编写,提出了实现多串口通信的三种方法,给出了实现的方法和步骤,并对三种方法进行了比较.实践证明,这三种模型均有效地实现了多串口通信.     

远程电表集抄系统软件设计与实现

通过分析当前电业局的需求,设计并实现了一种开放式多线程的远程电表集抄系统,介绍系统的总体设计及各模块的功能,详细描述了抄录数据功能和报表分析生成模块的具体实现。     

磁敏测速系统的数据采集平台实现

串口同步采集是工业控制应用的重要环节,为克服由于不准确的数据采集所带来的乘性误差,进而对多串口的同步采集进行了研究。利用VS2005编程环境,设计实现了多串口的上位机数据采集平台,该平台开辟线程对多个串口采取重叠读取方式,实现了对测速系统中大量的串口数据同步读取、保存并实现波形动态显示的功能,满足了智能测速系统的测速算法研究的需要。此平台可以广泛的应用在测速系统之中,也可辅助用于各种工业控制的高级要求。     

基于PCI总线的多功能可定制数据采集系统

为满足航空电子总线数据采集系统的通用性和多功能性,设计了基于PCI总线的多功能可定制数据采集系统;研究了相关总线板卡的驱动函数;采用自顶向下和模块化的方法设计了数据采集系统的系统运行管理模块、数据采集显示模块、数据分析处理模块和记录数据管理模块;使用了多线程、多视图、双缓存和Teechart控件等关键技术.设计实现的数...