Energy profile of rollback-recovery strategies in high performance computing

Extreme-scale computing is set to provide the infrastructure for the advances and breakthroughs that will solve some of the hardest problems in science and engineering. However, resilience and energy concerns loom as two of the major challenges for machines at that scale. The number of components that will be assembled in the supercomputers plays a fundamental role in these challenges. First, a large number of parts will substantially increase the failure rate of the system compared to the failure frequency of current machines. Second, those components have to fit within the power envelope of the installation and keep the energy consumption within operational margins. Extreme-scale machines will have to incorporate fault tolerance mechanisms and honor the energy and power restrictions. Therefore, it is essential to understand how fault tolerance and energy consumption interplay. This paper presents a comparative evaluation and analysis of energy consumption of three different rollback-recovery protocols: checkpoint/restart, message logging and parallel recovery. Our experimental evaluation shows parallel recovery has the minimum execution time and energy consumption. Additionally, we present an analytical model that projects parallel recovery can reduce energy consumption more than 37% compared to checkpoint/restart at extreme scale.     

资源管理系统中基于作业检查点的自动容错

本文提出了在资源管理系统中基于作业检查点实现自动容错支持,深入分析了作业与任务检查点分离、映像文件管理、自动恢复执行等关键技术。基于BLCR在SLURM中实现了作业的自动检查点/恢复,详细介绍了实现中的关键技术难题。分析与测试表明,检查点与恢复执行功能正确,并能有效缩短大规模作业成功运行所需的时间。     

Online scheduling on two parallel-batching machines with limited restarts to minimize the makespan

We study online scheduling on two unbounded parallel-batching machines with limited restarts to minimize the makespan. In this system jobs arrive over time and a batch can be restarted if and only if all the jobs in it have never been restarted. To tackle this difficult problem, we make the second-restart assumption whereby we can only interrupt a running batch B at time t if both machines are busy at time t and batch B has a later starting time than the other running batch. For this case, we provide a best online algorithm with a competitive ratio . For the general problem, we show that no online algorithms can have a competitive ratio less than 1.298, leaving a gap from 1.298 to 1.366.     

Abaqus重启动分析技术在风力机齿轮箱弹性支撑强度分析中的应用

齿轮箱弹性支撑强度分析系统大、组件多、网格多和工况多,常规的有限元分析时间很长、效率很低.采用Abaqus的重启动分析技术,对风力机齿轮箱弹性支撑进行强度分析,将复杂分析工况进行简化,大大地缩短分析时间,提高分析效率,且对分析精度没有影响.     

解大规模非对称线性方程组的Lanczos方法和精化Lanczos方法

引言科学工程计算的核心问题之一是数值求解大规模线性方程组,即给定n阶非奇异的非对1期贾仲孝等:解大规模非对称线性方程组的Lanczos方法和精化Lanczos方法称矩阵A和n维向量b,求一个。维向量x,使得Ax=b.(l)观察到该问题可以转化为     

防晃电技术及其在石化行业中的应用

由于石化行业具有工艺复杂,技术密集,高温高压和连续生产的特殊性质,针对其供电系统发生晃电时带来的不良影响,必须采取有效的防晃电技术来解决问题。为此,在重点分析晃电产生的原因、对供电回路的影响后,对5种常见防晃电技术的优、缺点进行了分析比较。最后介绍某石化企业在炼油区的几套关键装置上采用再启动控制器实现相关设备的晃电再启动的应用情况。     

面向IPv4／v6的BGP平滑重启的设计与实现

BGP通过平滑重启机制,可以最小化BGP重启所引起的对路由的负面影响,保证BGP在重启阶段仍然可以提供转发数据服务。文中着重于面向IPv4/v6的平滑重启能力的具体实现,介绍了平滑重启的工作过程和设计实现方法,并阐述了关键技术难点。目前,BGP的平滑重启功能已经在基于Linux的T比特路由器中实现。     

Virtual‐machine‐based heterogeneous checkpointing

Checkpointing an application is the act of saving the application's state during its execution on stable storage, so that if the application fails it can be restarted from the last saved state, thereby avoiding loss of the work that was already done. A heterogeneous checkpoint/restart mechanism allows one to restart an application on a possibly different hardware architecture and/or operating system than those in which the application was saved. This paper explores how to construct such a mechanism at the virtual machine level. That is, rather than dumping the entire state of the application process, the mechanism reported here dumps the state of the application as maintained by a virtual machine. During restart, the saved state is loaded into a new copy of the virtual machine, which continues running from there. The heterogeneous checkpoint/restart mechanism reported here was developed for the OCaml variant of ML. The paper reports on the main issues encountered in building such a mechanism and the design choices made, presents performance evaluations, and discusses some lessons and ideas for extending the work to native code OCaml and Java. Copyright © 2002 John Wiley & Sons, Ltd.     

整数标号的Brouwer不动点的构造性算法

本文提出计算标准单纯形上连续自映射不动点的一种整数标号的变维数单纯重复开始算法，该算法给出了Ｂｒｏｕｗｅｒ不动点定理一个新的构造性证明。数值结果表明新的算法是行之有效的。     

Kernel support for zero‐loss Internet service restart

Owing to long serving time and huge numbers of clients, Internet services can easily suffer from transient faults. Although restarting a service can solve this problem, information of the on‐line requests will be lost owing to the service restart, which is unacceptable for many commercial or transaction‐based services. In this paper, we propose an approach to achieve the goal of zero‐loss restart for Internet services. Under this approach, a kernel subsystem is responsible for detecting the transient faults, retaining the I/O channels of the service, and managing the service restart flow. In addition, some straightforward modifications to the service should be made to take advantage of the kernel support. To demonstrate the feasibility of our approach, we implemented the subsystem in the Linux kernel. Moreover, we modified a Web server and a CGI program to take advantage of the kernel support. According to the experimental results, our approach incurs little runtime overhead (i.e. less than 3.2%). When the service crashes, it can be restarted quickly (i.e. within 210 μs) with no information loss. Furthermore, the performance impact due to the service crash is small. These results show that the approach can efficiently achieve the goal of zero‐loss restart for Internet services. Copyright © 2006 John Wiley & Sons, Ltd.