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Study of the impact of replacement granularity and associated strategies on video caching

CLUSTER COMPUTING-THE JOURNAL OF NETWORKS SOFTWARE TOOLS AND APPLICATIONS 2005年第1期8卷 89-100页

作者： Balafoutis, E Panagakis, A Laoutaris, N Stavrakakis, I Univ Athens Dept Informat & Telecommun Athens 15784 Greece

Partial caching of large media objects such as video files has been proposed recently as the caching of entire objects can easily exhaust the storage resources of a proxy server. In this paper the idea of segmenting video files into chunks and applying replacement decisions at the chunk level rather than on entire videos is examined. It is shown that a higher byte bit ratio (BHR) can be achieved by appropriately adjusting the replacement granularity. The price paid for the improved BHR performance is that the replacement algorithm takes a longer time to converge to the steady state BHR. For the segmentation of video into chunks two methods are presented. The Fixed Chunk Size segmentation scheme that is rather simple and reveals the basic trade-off between byte hit ratio (BHR) and responsiveness to changes of popularity;the Variable Chunk Size segmentation scheme that uses the request frequencies to dynamically adjust the size of the chunk and is shown to be capable of combining a small response time with high BHR. Moreover, a variation of the fixed chunk size segmentation scheme is presented, which is shown to improve its performance by switching between different chunk sizes. Video segmentation is also considered as a mechanism to provide for caching differentiation based on access costs. By employing access cost dependent chunk sizes an overall access cost reduction is demonstrated.

关键词： video partial caching segmentation replacement algorithms replacement granularity

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2Q*: an effective, low-overhead, improved replacement algorithm for mail service applications in storage system

2Q*: an effective, low-overhead, improved replacement algori...

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IEEE International Symposium on Parallel and Distributed Processing with Applications (ISPA)

作者： Si, Chengxiang Meng, Xiaoxuan Xu, Lu Coordinat Ctr China Natl Comp Network Emergency Response Tech Team Beijing Peoples R China Chinese Acad Sci Inst Comp Technol Beijing Peoples R China

Any one algorithm cannot be effective for all applications;therefore, choosing one appropriate for one special application is very meaningful. In this article, we analyzed access patterns for mail service application, and acquired an algorithm appropriate for it. Moreover, based on analysis of performance characteristics for the current algorithm, we proposed an improved algorithm, called 2Q*, which behaves better than others for a full range of sizes. We also verify the effectiveness of 2Q* in a real buffer system, and join it with the main stream pre-fetch policy. The experimental results show that 2Q* can improve IO performance of mail service application effectively.

关键词： cache replacement algorithms mail service

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An Adaptive replacement Algorithm for Paged-Memory Computer Systems

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IEEE Transactions on Computers 1972年第10期C-21卷 1053-1061页

作者： Thorington, John M. Irwin, J. David Department of Electrical Engineering Auburn University Auburn Ala. United States Department of Electrical Engineering Auburn University Auburn Ala. United States

A general class of adaptive replacement schemes for use in paged memories is developed. One such algorithm, called SIM, is simulated using a probability model that generates memory traces, and the results of the simulation of this adaptive scheme are compared with those obtained using the best nonlookahead algorithms. A technique for implementing this type of adaptive replacement algorithm with state of the art digital hardware is also presented. Copyright © 1972 by The Institute of Electrical and Electronics Engineers, Inc.

关键词： memory Memory management memory systems paged paging replacement algorithms virtual memory

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An effective, low-overhead, improved replacement algorithm for mail service applications in storage system

An effective, low-overhead, improved replacement algorithm f...

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IEEE International Symposium on Parallel and Distributed Processing With Applications

作者： Si, Chengxiang Meng, Xiaoxuan Chen, Yuanfei Xu, Lu Institute of Computing Technology Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences Beijing China Institute of Computing Technology Chinese Academy of Sciences Beijing China

ISBN: (纸本)9780769541907

This paper analyzed the performance characteristics of classic 2Q algorithm when it was performed on mail-service workloads, and proposes an improved algorithm, called 2Q*. The simulation results show that 2Q* algorithm can outperform the other replacement algorithms, including the classic 2Q algorithm, for all the cache sizes and various mail-service workloads. To verify the simulation results in real system, we integrated the algorithm into FlexiCache, a partitioned buffer cache system, and joined it with a popular adaptive sequential pre-fetch policy properly. The experiment results verify the effectiveness of 2Q* algorithm for mail service applications. By joint with the prefetch policy, the performance is further improved. Moreover, its runtime overhead is also fairly low. © 2010 IEEE.

关键词： 2Q algorithm FlexiCache cache cache storage electronic mail mail service mail service applications partitioned buffer cache system prefetch policy replacement algorithm replacement algorithms storage system

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Implementation of the page fault frequency replacement algorithm

Implementation of the page fault frequency replacement algor...

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作者： Alexander Eugene Lancaster United States Naval Postgraduate School

学位级别：硕士

This paper investigates the implementation of the page fault frequency (PFF) replacement algorithm as the mechanism for selecting and replacing pages of programs loaded into the main memory of a multiprocessing, multiprogrammed computer system. The frequency at which an executing program requires a page of virtual memory, the PFF, provides a basis for judging the real memory requirements of the program. Operating difficulties of PFF that reduce its usefulness in a time-shared computer system (Michigan Terminal System) are discussed, and a means of implementing the algorithm is proposed.

关键词： replacement algorithms Virtual Memory Time-Sharing Systems Paged Memory Page Fault Michigan Terminal System MTS

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MEMORY MANAGEMENT FOR B-TREES

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PERFORMANCE EVALUATION 1985年第3期5卷 159-174页

作者： SPIRN, JR TSUR, S DIGITAL EQUIPMENT CORP HUDSONMA MICROELECTR & COMP TECHNOL CORP AUSTINTX

In this paper we consider the paging cost associated with the use of B-trees as indexes for random access files and data base systems. We measure the cost by the number of page faults as opposed to previously published analyses which are based on the number of pages accessed. We provide the analysis for two paging policies denoted LAP and LEC respectively. We show that the first policy is not optimal but nearly so and that the second is the optimal policy among a class of algorithms for sequences of independently chosen key references. Our simulation results show that, as a practical matter, the performance of LAP and LEC is nearly identical. Since LAP can easily be implemented we suggest it as a candidate for practical use.

关键词： B-Trees Indexed Files Random-Access Files Databases Paging replacement algorithms

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A partitioned on-chip virtual cache for fast processors

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JOURNAL OF SYSTEMS ARCHITECTURE 1997年第8期43卷 519-531页

作者： Kim, D Lee, J Park, S AJOU UNIV DIV INFORMAT & COMP ENGNKWONSUN GUSUWON 441749KYUNGGI DOSOUTH KOREA

In this paper, we propose a new virtual cache architecture that reduces memory latency by encompassing the merits of both direct-mapped cache and set-associative cache, The entire cache memory is divided into n banks, and the operating system assigns one of the banks to a process when it is created. Then, each process runs on the assigned bank, and the bank behaves like in a direct-mapped cache. If a cache miss occurs in the active home bank, then the data will be fetched either from other banks or from the main memory like a set-associative cache. A victim for cache replacement is selected from those that belong to a process which is most remote from being scheduled. Trace-driven simulations confirm that the new scheme removes almost as many conflict misses as does the set-associative cache, while cache access time is similar to a direct-mapped cache.

关键词： virtual cache conflict miss multiprogramming context switch process cache partitioning replacement algorithms

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Practically realizable efficient data allocation and replication strategies for distributed databases with buffer constraints

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2006年第9期17卷 1001-1013页

作者： Gu, Xin Lin, Wujuan Veeravalli, Bharadwaj Siemens Ltd Beijing 100102 Peoples R China Data Storage Inst Singapore 117608 Singapore Natl Univ Singapore Dept Elect & Comp Engn Singapore 117576 Singapore

In this paper, we address the performance of distributed database systems with buffer constraints. Specifically, our objective is to design and analyze efficient data allocation and replication strategies to minimize the total servicing cost for an arbitrary read/write request sequence, under finite buffer constraints of the nodes in the system. When the available buffer space in a node is not enough to store a copy of an object, the decision has to be made on whether or not we should evict one or more objects in use to give room for the new object copy. In this paper, we design and analyze the data replication strategies with the model of Dynamic Window Mechanism (DWM) algorithm jointly implemented with different types of object replacement strategies ( No replacement, LRU, and LFU) commonly found in practice. We consider situations wherein the object sizes are identical as well as heterogeneous. We will show the impact on the performance of the allocation and replication strategies due to the limited local database buffer capacities. We analyze and quantify theoretically ( using competitive analysis) the performances of all the proposed algorithms. Further, we perform rigorous simulation experiments to validate the findings with respect to several influencing parameters. Several useful conclusions are drawn based on the experimental results and we highlight the usefulness of the algorithms under different situations.

关键词： object allocation distributed database system competitiveness replacement algorithms caching communication cost

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PARC: A novel OS cache manager

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SOFTWARE-PRACTICE & EXPERIENCE 2018年第12期48卷 2193-2222页

作者： Chang, Hsung-Pin Chiang, Cheng-Pang Natl Chung Hsing Univ Dept Comp Sci & Engn Taichung Taiwan

To boost input-output performance, operating systems employ a kernel-managed caching space called the buffer cache or page cache. Given the limited size of a buffer cache, an effective cache manager is required to decide which blocks should be evicted from the cache. Previous cache managers use historical information to make replacement decisions. However, existing approaches are unable to maximize performance since they rely on limited historical information. Motivated by the limitations of existing solutions, this paper proposes a novel manager called the Pattern-assisted Adaptive Recency Caching (PARC) manager. PARC simultaneously uses the historical information of recency, frequency, and access patterns to estimate the locality strengths of blocks and, upon a cache miss, evicts the block with the least strength. Specifically, PARC exploits the reference regularities exhibited in past input-output behaviors to actively and rapidly adapt the recency and frequency information of blocks so as to precisely distinguish blocks with long- and short-term utility. Through comprehensive simulations on a variety of traces of different access patterns, we show that PARC is robust since, except for random workloads where the performance of each cache manager is similar, PARC always outperforms existing solutions.

关键词： buffer cache cache manager operating systems page cache replacement algorithms

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RACE: A robust adaptive caching strategy for buffer cache

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IEEE TRANSACTIONS ON COMPUTERS 2008年第1期57卷 25-40页

作者： Zhu, Yifeng Jiang, Hong Univ Maine Dept Elect & Comp Engn Orono ME 04469 USA Univ Nebraska Dept Comp Sci Lincoln NE 68588 USA

Although many block replacement algorithms for buffer caches have been proposed to address the well- known drawbacks of the LRU algorithm, they are not robust and cannot maintain a consistent performance improvement over all workloads. This paper proposes a novel and simple replacement scheme, called the Robust Adaptive buffer Cache management schemE ( RACE), which differentiates the locality of I/ O streams by actively detecting access patterns that are inherently exhibited in two correlated spaces, that is, the discrete block space of program contexts from which I/ O requests are issued and the continuous block space within files to which I/ O requests are addressed. This scheme combines the global I/ O regularities of an application and the local I/ O regularities of individual files that are accessed in that application to accurately estimate the locality strength, which is crucial in deciding which blocks are to be replaced upon a cache miss. Through comprehensive simulations on 10 real- application traces, RACE is shown to have higher hit ratios than LRU and all other state- of- the- art cache management schemes studied in this paper.

关键词： operating systems file systems management memory management replacement algorithms

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