Solaris多线程体系结构研究及多线程应用

本文介绍了从单线程向多线程操作系统过渡的原因 ,着重论述了Solaris双层多线程体系结构模型、多线程同步机制与函数接口 ,并对多线程实例进行了剖析。     

WindowsNT环境下的进程检查点设置与回卷恢复

阐述了WindowsNT环境下应用程序的检查点设置与回卷恢复机制,并介绍了设计和实现的检查点设置与恢复工具WinNTCkp.WinNTCkpt采用标准WindowsAPI函数,通过代码动态注入和对系统调用进行包裹的方法进行检查点设置与回卷恢复。与同类工具相比,WinNTCkpt具有不需修改应用程序源代码,不需对应用程序进行重新编译或连接,支持对用户文件内容的检查设置与回卷恢复的特点。WinNTCkpt是正在研制开发的高可用性机群计算环境的核心,也是在机群环境下实现进程迁移和负载平衡的技术基础。     

Unix进程检查点设置关键技术

Unix进程的检查点设置是实现分布/并行系统容错、重播调试、进程迁移、系统模拟和作业切换等功能的基础。该论文主要论述UNIX进程检查点基本信息的保存与恢复、文件检查点、检查点信息的优化等关键技术,最后介绍Libckpt、Condor以及自行设计的Libcsm等检查点设置工具。     

基于PVM的协调检查点设置关键技术

本文论述了基于PVM的并行程序运行回卷恢复系统设计和实现过程中的退出再加入PVM机制、任务号隐式映射机制、任务结束前同步机制、防止PVM库重入机制，信号与消息协同触发机制、应用任务初始化机制以及作为前述各机制实现基础的函数包裹与换名机制等关键技术。这些技术已经成功地应用于我们自主开发的ChaRM系统中，证明了技术的正确性和有效性。     

一种基于检查点的卷回恢复与进程迁移系统*

ChaRM是一种并行程序后向故障恢复与进程迁移系统.它不仅实现了对工作站机群系统瞬时故障的恢复,而且通过检查点设置时的Mirror存储技术和进程迁移技术,实现了对机群系统结点永久故障的恢复,并支持系统软硬件的在线维护、处理机资源的排他/限时使用和动态负载平衡等功能.文章主要介绍ChaRM系统的检查点设置与回卷恢复、进程迁移等实现技术,并给出了部分性能评测结果.     

复杂失效分布下的动态检查点设置

检查点技术是保障计算机系统可靠性的一种常用方法.通常假定系统失效的发生服从泊松分布,因此检查点是等间隔设置的.但近几年公布的现场数据表明以上假定不合实际.因此,首先利用现场失效数据对固定检查点间距方法的适应性进行分析,并提出两种检查点动态设置方法,它们根据系统前个阶段的失效信息动态地设置下一个检查点.模拟实验结果表明,所提出的方法在复杂失效分布下所获得的效果达到或者优于最优固定检查点的水平.     

一种基于准同步检查点的虚拟机卷回恢复算法

针对典型的云平台下虚拟化系统的特点,提出了一种结合选择性日志的准同步检查点算法VM_QSC:保持不同虚拟机节点固有的优化检查点周期,通过物理节点Hypervisor选择性地进行虚拟机的消息日志的稳定存储,在全局监控节点维护虚拟机一致线信息,保持全局的一致性。与传统的准同步检查点和同步检查点相比,该算法维持了虚拟机检查点设置的自主性,并显著降低了虚拟化系统的容错开销,可以有效应用于云计算环境下的虚拟资源管理和动态迁移。     

具有O(n)消息复杂度的协调检查点设置算法

协调检查点设置及回卷恢复技术作为一种有效的容错手段,已广泛地运用在集群等并行/分布计算机系统中.为了进一步降低协调检查点设置的时间和空间开销,提出了一种基于消息计数的协调检查点设置算法.该算法无须对底层消息通道的FIFO特性进行假设,并使同步阶段引入的控制消息复杂度由通常的O(n2)降低到O(n),有效地提高了系统的效率和扩展性.     

Solaris系统的安全设置技巧

本文叙述Solaris系统在安全方面的一些特点，通过对用户帐号、文件系统、用户登录、远程访问、系统服务安全性的设置，系统ASET（自动安全增强工具）的使用，以及如何使系统达到C2安全级，来说明一些设置技巧和管理经验。     

Predicting and Bounding the Speedup of Multithreaded Solaris Programs

In Solaris, threads are frequently relocated. The data associated with a relocated thread have to be moved from the cache of the old processor to the new processor. In order to avoid poor memory performance due to thread relocation, threads can be bound to processors—static scheduling. Finding a static schedule which results in maximum speedup is NP-hard. It is even difficult to determine if a static schedule is close to the optimal case or not. Here, a technique for predicting the speedup of multithreaded Solaris programs is presented. Based on an existing theoretical result, a lower bound on the maximal speedup is also obtained. The predicted speedup and the bound are based on recordings from a single-processor execution. When comparing the predictions with the real speedup using a multiprocessor with eight processors, we see that the predictions are very good. By comparing the speedup of a static schedule with the bound, we see that it is worthwhile to look for other schedules.     

多线程同步控制在构建Internet服务器中的应用研究

详细提出了一种在Internet上利用多线程程序设计技术构建服务器的方法，实验证明，它能很好地处理多线程共享资源同步问题。     

SWICH: A Prototype for Efficient Cache-Level Checkpointing and Rollback

Existing cache-level checkpointing schemes do not continuously support a large rollback window. Immediately after a checkpoint, the number of instructions that the processor can undo falls to zero. To address this problem, we introduce Swich, an FPGA-based prototype of a new cache-level scheme that keeps two live checkpoints at all times, forming a sliding rollback window that maintains a large minimum and average length     

基于检查点和Rejuvenation的软件运行模型分析

近来的研究表明,长时间运行的通信软件往往存在老化现象。为防止软件老化引起的突发性系统停机,提高系统的可靠性,人们提出了一种预防性的软件容错策略,称为rejuvenation。由于它的过程复杂,总的停机成本仍然是可观的。检查点是一种轻量级的软件容错策略,其成本远小于rejuvenation的成本。该文通过合理结合rejuvenation和检查点技术,实现了降低总的系统停机成本的目的。文中给出了系统的Petri网模型,并结合实例进行了分析。     

面向大规模MPI程序的应用级checkpointing技术

应用级checkpointing是一种在大规模科学计算领域中备受关注的容错技术.但是应用级checkpointing技术要求用户决定哪些是需要保存的关键数据,这增加了用户的负担.介绍一个基于MPI并行程序活跃变量分析的源到源的预编译工具ALEC,它可用于辅助应用级checkpointing.在一个512处理器的Cluster系统上,对经过ALEC编译的5个Fortran/MPI应用进行了性能评测.结果表明,ALEC能够有效减小checkpoint的大小和应用级checkpointing保存和恢复的开销.     

A Survey of Analytic Models of Rollback and Recovery Stratergies

There are several ways to increase system reliability. Choosing the most cost-effective one is not easy, but models such as those outlined in this paper can help.     

A Simple Sequential Reasoning Approach for Sound Modular Verification of Mainstream Multithreaded Programs

Reasoning about multithreaded object-oriented programs is difficult, due to the non-local nature of object aliasing, data races, and deadlocks. We propose a programming model that prevents data races and deadlocks, and supports local reasoning in the presence of object aliasing and concurrency. Our programming model builds on the multi-threading and synchronization primitives as they are present in current mainstream languages. Java or C# programs developed according to our model can be annotated by means of stylized comments to make the use of the model explicit. We show that such annotated programs can be formally verified to comply with the programming model. In other words, if the annotated program verifies, the underlying Java or C# program is guaranteed to be free from data races and deadlocks, and it is sound to reason locally about program behavior. Our approach supports immutable objects as well as static fields and static initializers. We have implemented a verifier for programs developed according to our model in a custom build of the Spec# programming system, and have validated our approach on a case study.