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Improving Networked File System Performance Using a Locality-Aware Cooperative Cache Protocol

IEEE TRANSACTIONS ON COMPUTERS 2010年第11期59卷 1508-1519页

作者： Jiang, Song Zhang, Xuechen Liang, Shuang Davis, Kei Wayne State Univ Dept Elect & Comp Engn 5050 Anthony Wayne Dr Detroit MI 48202 USA Ohio State Univ Dept Comp Sci & Engn Columbus OH 43210 USA Los Alamos Natl Lab Los Alamos NM 87545 USA

In a distributed environment, the utilization of file buffer caches in different clients may greatly vary. Cooperative caching has been proposed to increase cache utilization by coordinating the shared usage of distributed caches. It allows clients that would more greatly benefit from larger caches to forward data objects to peer clients with relatively underutilized caches. To support such coordination, global cache utilization must be dynamically evaluated. This, in turn, requires an effective analysis of application data access patterns. Existing coordination protocols are demonstrably suboptimal in this respect, exhibiting inefficient memory utilization and undue interference among clients. We propose a locality-aware cooperative caching protocol, called LAC, that is based on analysis and manipulation of data block reuse distance to effectively predict cache utilization and the probability of data reuse at each client. Using a dynamically adaptive synchronization technique, we keep local information up to date and consistently comparable across clients. The system is highly scalable in the sense that global coordination is achieved without centralized control. We have conducted thorough trace-driven simulation experiments to assess the performance differences between LAC and various existing protocols representative of the general class. Using a realistic and representative cost model, we show that the LAC protocol significantly and consistently outperforms existing cooperative caching protocols, demonstrating high and balanced utilization of caches across all clients. In our experiments, LAC reduces block access time by up to 36 percent, with an average of 31 percent, over the system without peer cache coordination, and reduces block access time by up to 22 percent, with an average of 13 percent, over the best performer of the existing protocols.

关键词： replacement algorithm locality cooperative caching networked file system

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Architecture of Multimedia Proxy Caching over the Internet

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Journal of Beijing Institute of Technology 2004年第4期13卷 355-359页

作者：潘浩潘天泉宋瀚涛王大震 School of Information Science and Technology Beijing Institute of Technology Beijing100081 China Department of Architecture and Engineering North China of Institute of Science and Technology Beijing101601 China

Streaming media data have strict delay and loss requirements, which cannot be adequately supported by the current Internet. Proxy caching technology is introduced to alleviate the effect of the bottleneck bandwidth on the transporting quality. A new architecture of multimedia proxy caching is given to solve the problem of the traditional Web caching technology for the multimedia streaming. The mixed media management module and the (resource) management module are added to this architecture, the prefetching and replacement method is studied considering the characteristics of streaming media data, the concept of weighed popularity is given to enhance the (exactness) of the replacement algorithm.

关键词： streaming media proxy caching quality of service replacement algorithm

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A ZERO-ONE LAW FOR RANDOM SUBGROUPS OF SOME TOTALLY DISCONNECTED GROUPS

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TRANSFORMATION GROUPS 2009年第4期14卷 787-800页

作者： Glasner, Yair Ben Gurion Univ Negev Dept Math IL-84105 Beer Sheva Israel

Let A be a locally compact group topologically generated by d elements and let k > d. Consider the action, by precomposition, of Gamma = Aut(F(k)) on the set of marked, k-generated, dense subgroups D(k,A) := {eta epsilon Hom(F(k,A))| <()over bar> = A}. We prove the ergodicity of this action for the following two families of simple, totally disconnected, locally compact groups: A = PSL(2)(K) where K is a non-Archimedean local field (of characteristic not equal 2);A = Aut(0)(T(q+1))| the group of orientation- preserving automorphisms of a q + 1 regular tree, for q >= 2. In contrast, a recent result of Minsky's shows that the same action fails to be ergodic for A = PSL(2)(C) and, when k is even, also for A = PSL(2)(R). Therefore, if k >= 4 is even and K is a local field (with char(K) not equal 2), the action of Aut(F(k)) on D(k,PSL2(K)) is ergodic if and only if K is non-Archimedean. Ergodicity implies that every "measurable property" either holds or fails to hold for almost every k-generated dense subgroup of A.

关键词： PRODUCT replacement algorithm DISTRIBUTING POINTS AUTOMORPHISM GROUP HECKE OPERATORS REGULAR TREES T-SYSTEMS PRESENTATIONS CONNECTIVITY GENERATORS GRAPH Action connectivity replacement algorithm

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VSWS - THE VARIABLE-INTERVAL SAMPLED WORKING SET POLICY

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 1983年第3期9卷 299-305页

作者： FERRARI, D YIH, YY UNIV CALIF BERKELEY ELECTR RES LABBERKELEYCA 94720 BELL TEL LABS INC HOLMDELNJ 07733

A local variable-size memory management policy has been developed. The variable-interval sampled working set (VSWS) is a working-set-like algorithm that exhibited a static performance similar to that of the sampled working set (SWS) policy and a dynamic performance better than SWS. Simpler hardware support requirements and a lower number of process suspensions for use bit scanning purposes are 2 advantages of VSWS over SWS. Because memory demands are increasing in important applications, along with the technology-driven trend toward smaller page sizes, bit scanning overhead use is apt to become a prime characteristic of memory policies which base their estimation of the current locality on the information contained in the use bits. Before local variable-size policies become really workable options to the global policies in most virtual memory systems used today, schemes for reducing the overhead of VSWS or SWS must be studied in depth.

关键词： Working Set Policy Damped Working Set Policy Local replacement Policy Memory Management Page Fault Frequency Policy Program Behavior replacement algorithm Sampled Working Set Policy Variable Size Policy Virtual Memory

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Coordinated multilevel buffer cache management with consistent access locality quantification

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IEEE TRANSACTIONS ON COMPUTERS 2007年第1期56卷 95-108页

作者： Jiang, Song Davis, Kei Zhang, Xiaodong Wayne State Univ Dept Elect & Comp Engn Detroit MI 48202 USA Los Alamos Natl Lab Performance & Architecture Lab Comp & Computat Sci Div Los Alamos NM 87545 USA Ohio State Univ Dept Comp Sci & Engn Columbus OH 43210 USA

This paper proposes a protocol for effective coordinated buffer cache management in a multilevel cache hierarchy typical of a client/server system. Currently, such cache hierarchies are managed suboptimally-decisions about block placement and replacement are made locally at each level of the hierarchy without coordination between levels. Though straightforward, this approach has several weaknesses: 1) Blocks may be redundantly cached, reducing the effective total cache size, 2) weakened locality at lower-level caches makes recency-based replacement algorithms such as LRU less effective, and 3) high-level caches cannot effectively identify blocks with strong locality and may place them in low-level caches. The fundamental reason for these weaknesses is that the locality information embedded in the streams of access requests from clients is not consistently analyzed and exploited, resulting in globally nonsystematic, and therefore suboptimal, placement and replacement of cached blocks across the hierarchy. To address this problem, we propose a coordinated multilevel cache management protocol based on consistent access-locality quantification. In this protocol, locality is dynamically quantified at the client level to direct servers to place or replace blocks appropriately at each level of the cache hierarchy. The result is that the block layout in the entirely hierarchy dynamically matches the locality of block accesses. Our simulation experiments on both synthetic and real-life traces show that the protocol effectively ameliorates these caching problems. As anecdotal evidence, our protocol achieves a reduction of block accesses of 11 percent to 71 percent, with an average of 35 percent, over uniLRU, a unified multilevel cache scheme.

关键词： replacement algorithm locality multilevel caching networked file system

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ANALYSIS OF LONG-TERM FILE REFERENCE PATTERNS FOR APPLICATION TO FILE MIGRATION algorithmS

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 1981年第4期7卷 403-417页

作者： SMITH, AJ UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB BERKELEYCA 94720

In most large computer installations, files migrate from on-line disk to mass storage, returning to disk only when they are needed by an interactive text editor. A study of file usage has determined that the average file is used 2 or fewer times; the average number of references per file, however, is 10.6. This translates to a highly skewed distribution: most files are used very little, and a few are accessed a large number of times. Data produced by a study of file usage has formed the basis for the construction and evaluation of a number of file migration algorithms. The size of a file and the time since it was last used are most important in determining when to migrate the file from disk to mass storage.

关键词： Time Series Analysis File Migration Mass Storage Memory Hierarchies replacement algorithm

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Lazy-split B⁺-tree: a novel B⁺-tree index scheme for flash-based database systems

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DESIGN AUTOMATION FOR EMBEDDED SYSTEMS 2013年第1期17卷 167-191页

作者： Jin, Rize Cho, Hyung-Ju Lee, Sang-Won Chung, Tae-Sun Ajou Univ Dept Comp Engn Suwon 443749 South Korea Sungkyunkwan Univ Sch Informat & Commun Engn Suwon 440746 South Korea

Flash memory is rapidly being deployed as a data storage medium for embedded systems and tablet computers due to its shock resistance, fast access, and low power consumption, etc. However, it has some intractable characteristics, such as erase-before-write, asymmetric read/write/erase speed, and a limited number of write/erase cycles. Due to these hardware limitations, magnetic disk-based systems and applications can hardly make full use of the advantages of flash memory when adopting it directly for storage. For example, the frequent changes of B-tree can degrade the performance and negatively influence the lifespan of flash memory. Most state-of-the-art studies on flash-aware index design focused mainly on buffer and storage mechanisms whereby they can obtain efficient I/Os to flash memory. In this paper, we identify the problems inherent in the related studies, and then introduce the concepts of lazy-split, modify-two-node, and semi-clean, which make possible the construction of a novel index solution, the Lazy-Split B+-tree (LSB+-tree). In detail, by their introduction, the first concept of LSB+-tree can efficiently reduce the number of node splits, the second can reduce the number of node modifications, and the last can make a further improvement on buffer space utilization and flash writes reduction.

关键词： B+-Tree Splitting policy replacement algorithm Index manager Flash memory

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OPTIMIZATION OF I/O SYSTEMS BY CACHE DISKS AND FILE MIGRATION - A SUMMARY

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PERFORMANCE EVALUATION 1981年第3期1卷 249-262页

作者： SMITH, AJ UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB BERKELEYCA 94720 STANFORD UNIV STANFORD LINEAR ACCELERATOR CTRSTANFORDCA 94305

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.

关键词： File migration Disk Disk Cache Cache Controller Buffer replacement algorithm Input/Output File Systems

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Construction of Distributed Cache Mechanism in Database Laboratorial Curriculum Design

Construction of Distributed Cache Mechanism in Database Labo...

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IEEE International Symposium on IT in Medicine and Education

作者： Zhang Cai-ming Liu Hui Shandong Econ Univ Comp Sci & Technol Dept Jinan 250014 Peoples R China

ISBN: (纸本)9781424425105

With the development of Internet Technology, in most universities and colleges, the education researches and innovation about professional curriculum of computer science & technology have occurred continually. In our database laboratorial curriculum design, we put forward higher requirements with the performance in Decision Support System (DSS). In order to improve the query response-time in DSS, this paper proposes a new DSS architecture with Distributed Cache Mechanism, gives the working flow of the system, and introduces an admission & replacement algorithm. Experimental results show that the system performance is favorable.

关键词： Curriculum Design System performance Cache memory universities Database Technological Innovations Distribute replacement algorithm Reaction Time

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Analyse d'un algorithme de gestion simultanée mémoire centrale - disque de pagination

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Acta Informatica 1974年第4期3卷 321-345页

作者： Gelenbe, E. Lenfant, J. Potier, D. Département de Mathématiques Centre Scientifique et Polytechnique Université de Paris XIII Saint Denis F-93 France Laboratoire de Recherche en Informatique et Automatique IRIA Rocquencourt 78 France C.N.R.S. Département de Mathématiques et Informatique Université de Rennes Rennes F-35 France

Commonly used memory management strategies in a paged environment optimize separately the page-fault rate (by proper choice of a replacement algorithm) and the response time of the paging drum (by a shortest-access-time-first discipline with multiple sectors). In this paper we consider replacement strategies which attempt to maximize useful CPU utilisation and hence throughput by choosing the page to be replaced on the basis of its probability of reference as well as on the rapidity with which the page can be removed from main memory, assuming that a fixed-head disk or drum is used as a secondary memory. An analysis of the approach is given using a mathematical model. Analytical results for the gain in CPU utilisation are obtained under mono-programming and numerical examples are presented illustrating the effects of variation of program behaviour and of variants of the replacement strategy. © 1974 Springer-Verlag.

关键词： Surgical Replantation Drum Store management main memory PARTICLE RAPIDITY variants metasomatism Reaction Time Drums central processing units fixed head secondary memory replacement algorithm

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