协作型虚拟机中设备虚拟化研究

针对当前系统虚拟化中设备模型难以通用、I/O执行效率低等问题,提出一种基于多核平台的设备虚拟化方案。将传统的消息式I/O处理转换成实时I/O处理,通过I/O传递协议消除I/O处理部件与虚拟机监控器(VMM)的紧耦合,在改善I/O处理效率的同时,提高设备虚拟化模型的通用性,结合协作型VMM完成对设备虚拟化的设计与实现。测试结果表明,该方案能提升I/O执行效率,适用于多种虚拟化系统。     

输入/输出子系统体系结构

输入输出(I/O)子系统体系结构的主要问题是中央处理机与I/O子系统之间活动的协调、从外部的I/O处理请求到I/O子系统基本操作之间的转换以及在I/O子系统内部对并行的各处理活动的管理。结构上的进展,例如数据与命令链、通道程序接口、键的自动搜索,旋转位置探测以及成组多路传输等,可以用上述这些基本的事件来评价。提出了许多新论点来说明现行设计优缺点,对于这方面今后的发展作了种种设想。     

支持异构集群并行的高能物理数据处理系统

传统集群计算系统无法充分利用本地磁盘的存储资源和I/O,大量网络I/O成为系统瓶颈,导致资源利用率降低,并造成高昂的存储和网络成本.使用Hadoop处理分析作业可有效利用本地磁盘存储和I/O资源,而集群资源统一管理工具Mesos则使用轻量化的设计和高效的通信机制,能在不同计算集群之间动态共享集群资源.为此,分析高能物理数据处理的特点,利用Mesos构建异构集群间资源共享的高能物理实验数据处理系统,实现Torque/Maui和Hadoop集群的集成.测试结果表明,该系统能够在集群间动态分配集群资源,并利用本地存储和磁盘I/O显著降低网络I/O,提高集群资源利用率.     

用嵌入式系统的SPI模块实现I2C总线通信

I2C一般用于单主机系统中.在单主机系统中,通信系统的主机可能没有I2C接口模块,而直接使用主机的I/O口进行总线模拟.也就是使用一个I/O口模拟I2C总线的SCL时钟信号,使用另外一个I/O口模拟I2C总线的SDA数据信号.     

基于FPGA的I/O控制器的设计和实现

对于计算机信息系统受到攻击基本上可以分为基于CPU和I/O控制器这两种。对于CPU的攻击已经被深入研究,各种成熟的对策也被广泛的应用。但是对于I/O控制器攻击的研究非常缺乏有效的保护机制。为了研究关于I/O控制器的攻击,使用FPGA可编程技术设计和实现了一款PCI Express总线的平台。平台能产生任意种类的关于PCI Express事务层的信息包,为研究各类I/O控制器的攻击提供了基础。     

一种基于虚拟机的高效磁盘I/O特征分析方法

于磁盘系统的机械运动本质,磁盘系统I/O往往会成为计算机系统的性能瓶颈.为了有效地提高系统性能,收集和分析应用系统的磁盘I/O特征信息将成为性能优化工作的重要基础.与以往I/O特征分析方法不同,给出了一种基于Xen 3.0虚拟机系统的磁盘I/O特征在线分析方法.在虚拟机环境下,该磁盘I/O特征采集方法可以透明地应用于任意无须修改的操作系统.该方法可以高效地在线采集多种基本I/O特征数据,其中包括:磁盘I/O块大小、I/O延迟、I/O时间间隔、I/O空间局部性、时间局部性以及磁盘I/O操作热点分布.通过测试和分析,该在线I/O分析方法有着较小的系统开销,并且对应用系统I/O性能的影响很小.此外,还给出了在大文件拷贝、基于Filebench的filemirco和varmail等工作负载下的I/O特征分析结果.     

基于FFT并行算法的并行I/O性能的研究

该研究对象为并行计算机的I/O性能,将任务分发给不同的处理结点,通过进程间的相互协调、有序合作完成FFT并行算法的实现。在完成任务的过程中,通过记录I/O时间与计算时间,求出I/O性能与计算性能,通过分析比较数据从而认识I/O性能的重要性。研究计算机的I/O性能对于如何进一步改进系统以及提高资源利用率具有重要意义。     

基于WordSmith软件的平行语料库加工处理系统设计

平行语料库加工处理过程中,传统的系统很难将当前字的标记与其它序列字符的同现特征统计出来,导致切分错误情况频频发生.为此,设计基于WordSmith软件的平行语料库加工处理系统.在硬件设计上,使用S3C6410处理器实现文本分析功能,生成标注文件,用于后续加工处理;在软件设计上,使用WordSmith软件提取出语料库中的...     

并行文件系统的设计

随着处理机速度和网络传输速度越来越快,外部1/0设备的速度却相对落后了三、四个数量级,已经成为影响整个系统速度的瓶颈.另一方面,诸如多媒体、图像处理这些应用所需要的数据传输率越来越大,因而有必要支持高速的I/O子系统以弥补磁盘与处理机之间速度的差异,支持I/0密集的应用之高数据传输率。为了提高1/0速率,提供大的I/O带宽,在硬件结构上可以并行使用磁盘来解决。对于一个MIMD系统中使用多磁盘输入/输出子系统,     

多模式并行I/O测试程序Jetter的研究与实现

并行I/O系统有多种存取模式,它们有各自的存取特点和适用范围。为了获得不同模式下的系统性能,并行I/O测试中往往要综合使用多种微测试程序。这不仅要求用户深入了解并行I/O的特点,而且要求他们熟悉各种并行I/O微测试程序的输入与输出。提出并实现了一个并行I/O测试Jetter,它从接口类型、存取模式和进程－文件关系的角度划分了并行I/O接口,不仅能够测试I/O系统在上述模式下的性能,而且简化了测试工作。实际应用Jetter表明,并行I/O系统对不同模式的支持效果不同,最高差异可以达到两个数量级以上,这些测试结论有助于用户开发高质量的并行程序。     

Input/output optimization and disk architectures: A survey

The file system, and the components of the computer system associated with it (disks, drums, channels, mass storage, tapes and tape drives, controllers, I/O drivers, etc.) comprise a very substantial fraction of most computer systems; substantial in several aspects including amount of operating system code, expense for components, physical size and effect on performance. In this paper we survey the state of the art file and I/O system design and optimization as it applies to large data processing installations. In a companion paper, some research results applicable to both current and future system designs are summarized.Among the topics we discuss is the optimization of current file systems, where some material is provided regarding block size choice, data set placement, disk arm scheduling, rotational scheduling, compaction, fragmentation, I/O multipathing and file data structures. A set of references to the literature, especially to analytic I/O system models, is presented. The general tuning of file and I/O systems is also considered. Current and forthcoming disk architectures are the second topic. The count key data architecture of current disks (e.g. IBM 3350, 3380) and the fixed block architecture of new products (IBM 3310, 3370) are compared. The use of semiconductor drum replacements is considered and some commercially available systems are briefly described.     

基于I/O空闲率的硬盘功耗建模与评估方法研究

存储设备的功耗在整个计算机系统尤其是数据中心所占的比例已经越来越大。要进行硬盘功耗优化,在缺少硬件直接测量硬盘功耗的情况下就需要对硬盘功耗进行建模。现代操作系统通过文件系统层进行硬盘I/O操作管理,并提供实时监控数据。通过对EXT2、EXT4和NILFS2等常用文件系统的硬盘I/O过程进行实验分析,发现不同的文件系统对硬盘功耗具有不同的影响,为了刻画这种差异性,提出基于I/O空闲率的硬盘功耗建模与评估方法。同时使用I/O空闲率来指导硬盘进行功耗优化,将视频播放器的I/O空闲率由4.79%提高到96.55%,硬盘的功耗降低45.28%。     

并行文件系统的设计

在大规模并行处理巨型机（ＭＰＰ）的设计中，提高Ｉ／Ｏ性能同提高计算能力和通信能力同样重要。并行文件系统（ＰＦＳ）在多个Ｉ／Ｏ结点的多个磁盘上，分布文件系统和文件的磁盘块，将文件读写在计算结点转化成多个对物理块的直接Ｉ／Ｏ请求，利用预读，预分配，磁盘缓冲式区和异步Ｉ／Ｏ增加Ｉ／Ｏ的并发生，在特定的文件使用模式下，也是ＭＰＰ应用的主要Ｉ／Ｏ模式，获得很高的Ｉ／Ｏ效率。     

并行文件系统扩容与I/O节点负载平衡策略

在规模并行处理系统ＭＰＰ商业化应用中,并行文件系统容量与Ｉ／Ｏ节点的负载平衡一直是挖掘整个系统并行性,进而提高系统性能的关键问题之一。本文从分析Ｐａｒａｇｏｎ大规模并行处理系统的体系结构和并行文件系统的体系结构出发,给出了并行文件系统的扩容策略,使用ＭＰＰ系统的Ｉ／Ｏ节点平衡负载理论模型,给出了实际工程应用中的负载平衡策略。     

基于C++的Windows CE文件I/O处理技术

通过对Windows文件系统的分析以及各种文件I／O处理方法的进一步研究,发现大多数Windows CE应用程序的文件I/O处理都是使用基于Win32 API函数的方法或基于MFC类库中CFile类的方法,本文讨论了这两种文件处理方法的基本原理及其运用。     

An adaptive cache coherence protocol specification for parallel input/output systems

Caching has been intensively used in memory and traditional file systems to improve system performance. However, the use of caching in parallel file systems and I/O libraries has been limited to I/O nodes to avoid cache coherence problems. We specify an adaptive cache coherence protocol that is very suitable for parallel file systems and parallel I/O libraries. This model exploits the use of caching, both at processing and I/O nodes, providing performance improvement mechanisms such as aggressive prefetching and delayed-write techniques. The cache coherence problem is solved by using a dynamic scheme of cache coherence protocols with different sizes and shapes of granularity. The proposed model is very appropriate for parallel I/O interfaces, such as MPI-IO. Performance results, obtained on an IBM SP2, are presented to demonstrate the advantages offered by the cache management methods proposed.     

Optimization of I/O systems by cache disks and file migration: A summary

The file system, and the components of the computer system associated with it (disks, drums, channels, mass storage, tapes and tape drives, controllers, I/O drivers, etc.) comprise a very substantial fraction of most computer systems; substantial in several aspects, including amount of operating system code, expense for components, physical size and effect on performance. In a companion paper, we surveyed the traditional methods for optimizing the I/O system. We then examined disk and I/O system architecture in IBM type systems, and indicated shortcomings and future directions. In this paper we go one step further and summarize research by the author on two topics: cache disks and file migration. Cache disks are disks which have an associated cache which buffers recently used tracks of data. The case for cache disks is presented, and some of the issues are discussed. Parameter values for some aspects of the cache design are suggested. The second part of this paper summarizes the author's work on file migration, by which files are migrated between disk and mass storage as needed in order to effectively maintain on-line a much larger amount of information than the disks can hold. Some of the algorithms investigated are discussed, and the basic results are presented.     

Optimization of I/O systems by cache disks and file migration: A summary

The file system, and the components of the computer system associated with it (disks, drums, channels, mass storage tapes and tape drives, controllers, I/O drivers, etc.) comprise a very substantial fraction of most computer systems; substantial in several aspects, including amount of operating system code, expense for components, physical size and effect on performance. In a comparison paper, we surveyed the traditional methods for optimizing the I/O system. We then examined disk and I/O system architecture in IBM type systems, and indicated shortcomings and future directions. In this paper we go one step further and summarize research by the author on two topics: cache disks and file migration. Cache disks are disks which have an associated cache which buffers recently used tracks of data. The case for cache disks is presented, and some of the issues are discussed. Parameter values for some aspects of the cache design are suggested. The second part of this paper summarizes the author's work on file migration, by which files are migrated between disk and mass storage as needed in order to effectively maintain on-line a much larger amount of information than the disks can hold. Some of the algorithms investigated are discussed, and the basic results are presented.     

I/O performance of an RAID-10 style parallel file system

Without any additional cost, all the disks on the nodes of a cluster can be connected together through CEFT-PVFS, an RAID-10 style parallel file system, to provide a multi-GB/s parallel I/O performance.I/O response time is one of the most important measures of quality of service for a client. When multiple clients submit data-intensive jobs at the same time, the response time experienced by the user is an indicator of the power of the cluster. In this paper, a queuing model is used to analyze in detail the average response time when multiple clients access CEFT-PVFS. The results reveal that response time is with a function of several operational parameters. The results show that I/O response time decreases with the increases in I/O buffer hit rate for read requests, write buffer size for write requests and the number of server nodes in the parallel file system, while the higher the I/O requests arrival rate, the longer the I/O response time. On the other hand, the collective power of a large cluster supported by CEFT-PVFS is shown to be able to sustain a steady and stable I/O response time for a relatively large range of the request arrival rate.