Integrating Runtime Consistency Models for Distributed Computing

How should distributed systems preserve consistency in the presence of concurrency and failures? For systems designed as assemblies of independently developed components, concurrent access to data or data structures would normally arise within individual programs, and be controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operations are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group-oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems-often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony to interact with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.     

面向集合预报的高性能计算环境

集合预报中需要大量的高性能计算资源对海量数据进行实时分析和处理,高效的资源管理和数据共享将有效提高预报的效率和时效性。本文在分析集合预报的特点和需求的基础上,设计了基于元数据提取的海量数据管理方案和基于虚拟组织的高性能计算资源管理方案,并采用网格技术对这些资源进行有效管理和共享,为分布在各个地域、不同组织的气象科学家提供一个高效共享的协同开发平台,达到有效提高预报结果的时效性并推动中尺度天气预报事业发展的目标。     

Hardware Technologies for High-Performance Data-Intensive Computing

Data-intensive problems challenge conventional computing architectures with demanding CPU, memory, and I/O requirements. Experiments with three benchmarks suggest that emerging hardware technologies can significantly boost performance of a wide range of applications by increasing compute cycles and bandwidth and reducing latency.     

普适计算应用时空性质的运行时验证

运行时验证是提升普适计算应用可靠性的重要手段.这类应用的很多性质同时涉及时间关系和空间位置关系,这样的时空性质给运行时验证带来了特有的挑战.一方面,传统的时态逻辑难以描述空间性质;另一方面,适合描述空间性质的Ambient Logic在真值不确定等情况下不能很好支持有限轨迹中时间性质的描述.为支持普适计算应用时空性质的运行时验证,本文引入三值逻辑语义,提出了AL₃（3-valued Ambient Logic）;并在此基础上设计实现了基于AL₃的性质检验算法和运行时监控器.最后,通过案例分析和运行效率实验阐明了所提方法的有效性和可行性.     

基于Portlet的高性能计算Portal

提出基于Portlet的高性能计算Ponal——HPCP,提供一个简单、通用、安全、可定制的Web作业管理系统,支持作业提交、查询、终止、目录列表及文件内容实时查看、大文件的数据流无缓存下载等功能。理论分析和实际测试表明。HPCP具有类似桌面应用程序的用户友好、交互性等特点,且有良好的可扩展性和安全性。     

Investigating Autonomic Runtime Management Strategies for SAMR Applications

Dynamic structured adaptive mesh refinement (SAMR) techniques along with the emergence of the computational Grid offer the potential for realistic scientific and engineering simulations of complex physical phenomena. However, the inherent dynamic nature of SAMR applications coupled with the heterogeneity and dynamism of the underlying Grid environment present significant research challenges. This paper presents application/system sensitive reactive and proactive partitioning strategies that form a part of the GridARM autonomic runtime management framework. An evaluation using different SAMR kernels and system workloads is presented to demonstrate the improvement in overall application performance.     

Ad Hoc File Systems for High-Performance Computing

Storage backends of parallel compute clusters are still based mostly on magnetic disks,while newer and faster storage technologies such as flash-based SSDs or non-volatile random access memory(NVRAM)are deployed within compute nodes.Including these new storage technologies into scientific workflows is unfortunately today a mostly manual task,and most scientists therefore do not take advantage of the faster storage media.One approach to systematically include nodelocal SSDs or NVRAMs into scientific workflows is to deploy ad hoc file systems over a set of compute nodes,which serve as temporary storage systems for single applications or longer-running campaigns.This paper presents results from the Dagstuhl Seminar 17202"Challenges and Opportunities of User-Level File Systems for HPC"and discusses application scenarios as well as design strategies for ad hoc file systems using node-local storage media.The discussion includes open research questions,such as how to couple ad hoc file systems with the batch scheduling environment and how to schedule stage-in and stage-out processes of data between the storage backend and the ad hoc file systems.Also presented are strategies to build ad hoc file systems by using reusable components for networking and how to improve storage device compatibility.Various interfaces and semantics are presented,for example those used by the three ad hoc file systems BeeOND,GekkoFS,and BurstFS.Their presentation covers a range from file systems running in production to cutting-edge research focusing on reaching the performance limits of the underlying devices.     

面向云服务的高性能计算柔性服务平台

随着云计算的深入应用,为用户提供高质量的远程高性能云服务成为当前研究的热点。文章提出了面向云服务的高性能计算柔性服务平台,该平台通过虚拟化技术、图形化和面向对象的技术等,设计和实现了全新的高性能计算环境,具有工具整合程度高、用户界面友好等特点,可为远程云服务提供必要支持。     

远程高性能计算软件环境需求及架构设计

高性能计算软件环境对高性能计算机的推广应用具有重要意义。针对高性能计算的一般过程,本文讨论了高性能计算软件环境的需求,给出了远程高性能计算软件环境的架构以及客户端和计算服务器软件的结构设计,探讨了客户端和计算服务器间信息报文的主要类型及报文格式。     

Mochi: Composing Data Services for High-Performance Computing Environments

Technology enhancements and the growing breadth of application workflows running on high-performance computing(HPC)platforms drive the development of new data services that provide high performance on these new platforms,provide capable and productive interfaces and abstractions for a variety of applications,and are readily adapted when new technologies are deployed.The Mochi framework enables composition of specialized distributed data services from a collection of connectable modules and subservices.Rather than forcing all applications to use a one-size-fits-all data staging and I/O software configuration,Mochi allows each application to use a data service specialized to its needs and access patterns.This paper introduces the Mochi framework and methodology.The Mochi core components and microservices are described.Examples of the application of the Mochi methodology to the development of four specialized services are detailed.Finally,a performance evaluation of a Mochi core component,a Mochi microservice,and a composed service providing an object model is performed.The paper concludes by positioning Mochi relative to related work in the HPC space and indicating directions for future work.     

The Promise of High-Performance Reconfigurable Computing

Several high-performance computers now use field-programmable gate arrays as reconfigurable coprocessors. The authors describe the two major contemporary HPRC architectures and explore the pros and cons of each using representative applications from remote sensing, molecular dynamics, bioinformatics, and cryptanalysis.     

高性能小型无人机导航计算平台设计

针对小型无人机长航时、高精度的导航要求,研究了一种低成本、高性能小型无人机组合导航系统。构建了由惯性元件、气压高度计和双天线GPS姿态测量系统构成的组合导航计算平台,采用了基于FPGA的SOPC技术,实现了系统功能的高度集成。针对信息融合算法中滤波延时较大的问题,采用了非对称双核的设计,在进行卡尔曼滤波的同时完成了捷联解算,大幅提高了导航信息的更新频率。     

基于网格的分布并行计算策略

网格计算为用户处理很多复杂问题提供了新方法,用网格实现大规模分布并行计算是必然的趋势。文章给出了基于网格中间件Globus Toolkit来实现分布并行计算的两种策略：紧密耦合并行程序和松散耦台并行服务,并给出实现这两种策略的实现方法,为实现分布并行计算提供了新方法。最后根据所提出的并行计算策略,在网格计算环境下实现了一个分布并行计算实例,并给出了相应的试验结果。     

Runtime Techniques to Enable a Highly-Scalable Global Address Space Model for Petascale Computing

Over the past decade, the trajectory to the petascale has been built on increased complexity and scale of the underlying parallel architectures. Meanwhile, software developers have struggled to provide tools that maintain the productivity of computational science teams using these new systems. In this regard, Global Address Space (GAS) programming models provide a straightforward and easy to use addressing model, which can lead to improved productivity. However, the scalability of GAS depends directly on the design and implementation of the runtime system on the target petascale distributed-memory architecture. In this paper, we describe the design, implementation, and optimization of the Aggregate Remote Memory Copy Interface (ARMCI) runtime library on the Cray XT5 2.3 PetaFLOPs computer at Oak Ridge National Laboratory. We optimized our implementation with the flow intimation technique that we have introduced in this paper. Our optimized ARMCI implementation improves scalability of both the Global Arrays programming model and a real-world chemistry application—NWChem—from small jobs up through 180,000 cores.     

Alias Analysis in Java with Reference-Set Representation for High-Performance Computing

In this paper, a flow-sensitive, context-insensitive alias analysis in Java is proposed. It is more efficient and precise than previous analyses for C++, and it does not negatively affect the safety of aliased references. To this end, we first present a reference-set alias representation. Second, data-flow equations based on the propagation rules for the reference-set alias representation are introduced. The equations compute alias information more efficiently and precisely than previous analyses for C++. Third, for the constant time complexity of the type determination, a type table is introduced with reference variables and all possible types for each reference variable. Fourth, an alias analysis algorithm is proposed, which uses a popular iterative loop method for an alias analysis. Finally, running times of benchmark codes are compared for reference-set and existing object-pair representation.     

The Paradigm of Power Bounded High-Performance Computing

Journal of Computer Science and Technology - Modern computer systems are increasingly bounded by the available or permissible power at multiple layers from individual components to data centers. To...     

Telegraphos: A Substrate for High-Performance Computing on Workstation Clusters

Networks of workstations and high-performance microcomputers have been rarely used for running parallel applications, because, although they have significant aggregate computing power, they lack the support for efficient message-passing and shared-memory communication. In this paper we presentTelegraphos, a distributed system that provides efficient message-passing and shared-memory support on top of a workstation cluster. We focus on the network interface of Telegraphos that provides a variety of shared-memory operations such as remote read, remote write, remote atomic operations, and DMA, all launched from user level without any intervention of the operating system. Telegraphos I, the Telegraphos prototype, has been implemented. Emphasis was placed on rapid prototyping, so the technology used was conservative: FPGAs, SRAMs, and TTL buffers.     

System-Level Resource Monitoring in High-Performance Computing Environments

Low-overhead resource monitoring is key to the successful management of distributed high-performance computing environments, particularly when applications have well-defined quality of service (QoS) requirements. The dproc system-level monitoring mechanisms provide tools both for efficiently monitoring system-level events and for notifying remote hosts of events relevant to their operation. Implemented as extension to the Linux kernel, dproc provides several key functions. First, utilizing the familiar /proc virtual filesystem, dproc extends this interface with resource information collected from both local and remote hosts. Second, to predictably capture and distribute monitoring information, dproc uses a kernel-level group communication facility, termed KECho, which implements events and event channels. Third, and the focus of this paper, is dproc's run-time customizability for resource monitoring, which includes the generation and deployment of monitoring functionality within remote operating system kernels. Using dproc, we show that (a) data streams can be customized according to a client's resource availabilities (dynamic stream management), (b) by dynamically varying distributed monitoring (dynamic filtering of monitoring information), an appropriate balance can be maintained between monitoring overheads and application quality, and (c) by performing monitoring at kernel-level, the information captured enables decision making that takes into account the multiple resources used by applications.