Download or read book Combining Hardware and Software Cache Coherence Strategies written by David J. Lilja and published by . This book was released on 1991 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "Efficiently maintaining cache coherence is a major problem in large-scale shared memory multiprocessors. Hardware directory schemes have very high memory requirements, while software-directed schemes must rely on imprecise compile-time memory disambiguation. Recently proposed dynamic directory schemes allocate pointers to blocks only as they are referenced, which significantly reduces their memory requirements, but they still allocate pointers to blocks that do not need them. We show how compiler marking can further reduce the directory size by allocating pointers only when necessary. Using trace-driven simulations, we find that the performance of this new approach is comparable to other coherence schemes, but with significantly lower memory requirements."
Download or read book Cache Memory Design and Performance Issues in Shared memory Multiprocessors written by Farnaz Mounes-Toussi and published by . This book was released on 1995 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 1993 International Conference on Parallel Processing written by Alok N. Choudhary and published by CRC Press. This book was released on 1993-08-16 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: This three-volume work presents a compendium of current and seminal papers on parallel/distributed processing offered at the 22nd International Conference on Parallel Processing, held August 16-20, 1993 in Chicago, Illinois. Topics include processor architectures; mapping algorithms to parallel systems, performance evaluations; fault diagnosis, recovery, and tolerance; cube networks; portable software; synchronization; compilers; hypercube computing; and image processing and graphics. Computer professionals in parallel processing, distributed systems, and software engineering will find this book essential to their complete computer reference library.
Download or read book A Primer on Memory Consistency and Cache Coherence written by Vijay Nagarajan and published by Morgan & Claypool Publishers. This book was released on 2020-02-04 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many modern computer systems, including homogeneous and heterogeneous architectures, support shared memory in hardware. In a shared memory system, each of the processor cores may read and write to a single shared address space. For a shared memory machine, the memory consistency model defines the architecturally visible behavior of its memory system. Consistency definitions provide rules about loads and stores (or memory reads and writes) and how they act upon memory. As part of supporting a memory consistency model, many machines also provide cache coherence protocols that ensure that multiple cached copies of data are kept up-to-date. The goal of this primer is to provide readers with a basic understanding of consistency and coherence. This understanding includes both the issues that must be solved as well as a variety of solutions. We present both high-level concepts as well as specific, concrete examples from real-world systems. This second edition reflects a decade of advancements since the first edition and includes, among other more modest changes, two new chapters: one on consistency and coherence for non-CPU accelerators (with a focus on GPUs) and one that points to formal work and tools on consistency and coherence.
Download or read book The Cache Coherence Problem in Shared Memory Multiprocessors written by Igor Tartalja and published by Wiley-IEEE Computer Society Press. This book was released on 1996-02-13 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book illustrates state-of-the-art software solutions for cache coherence maintenance in shared-memory multiprocessors. It begins with a brief overview of the cache coherence problem and introduces software solutions to the problem. The text defines and details static and dynamic software schemes, techniques for modeling performance evaluation mechanisms, and performance evaluation studies.
Download or read book Software Cache Coherence for Large Scale Multiprocessors written by University of Rochester. Department of Computer Science and published by . This book was released on 1994 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "Shared memory provides an attractive and intuitive programming model that makes good use of programmer time and effort. Shared memory however requires a coherence mechanism to allow caching for performance and to ensure that processors do not use stale data in their caches. We evaluate several algorithmic and architectural alternatives in the design space of NCC-NUMA machines with a globally-accessible physical address space. We present a new adaptive algorithm for software cache coherence that reduces interprocessor communication and scales to large numbers of processors; we compare it to existing software and hardware coherence schemes. We also evaluate (1) the tradeoffs among various write policies (write-through, write-back, write-through with a write-collect buffer) and (2) the effect on performance of using remote memory access. Finally, we observe that certain simple program changes can greatly improve performance. For example, we find that the use of reader-writer locks, synchronization variable relocation, and data structure padding and alignment can allow a protocol to avoid significant amounts of coherence overhead."
Download or read book A Primer on Memory Consistency and Cache Coherence written by Daniel Sorin and published by Morgan & Claypool Publishers. This book was released on 2011-03-02 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many modern computer systems and most multicore chips (chip multiprocessors) support shared memory in hardware. In a shared memory system, each of the processor cores may read and write to a single shared address space. For a shared memory machine, the memory consistency model defines the architecturally visible behavior of its memory system. Consistency definitions provide rules about loads and stores (or memory reads and writes) and how they act upon memory. As part of supporting a memory consistency model, many machines also provide cache coherence protocols that ensure that multiple cached copies of data are kept up-to-date. The goal of this primer is to provide readers with a basic understanding of consistency and coherence. This understanding includes both the issues that must be solved as well as a variety of solutions. We present both highlevel concepts as well as specific, concrete examples from real-world systems. Table of Contents: Preface / Introduction to Consistency and Coherence / Coherence Basics / Memory Consistency Motivation and Sequential Consistency / Total Store Order and the x86 Memory Model / Relaxed Memory Consistency / Coherence Protocols / Snooping Coherence Protocols / Directory Coherence Protocols / Advanced Topics in Coherence / Author Biographies
Download or read book Shared Memory Synchronization written by Michael L. Scott and published by Morgan & Claypool Publishers. This book was released on 2013-06-01 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: From driving, flying, and swimming, to digging for unknown objects in space exploration, autonomous robots take on varied shapes and sizes. In part, autonomous robots are designed to perform tasks that are too dirty, dull, or dangerous for humans. With nontrivial autonomy and volition, they may soon claim their own place in human society. These robots will be our allies as we strive for understanding our natural and man-made environments and build positive synergies around us. Although we may never perfect replication of biological capabilities in robots, we must harness the inevitable emergence of robots that synchronizes with our own capacities to live, learn, and grow. This book is a snapshot of motivations and methodologies for our collective attempts to transform our lives and enable us to cohabit with robots that work with and for us. It reviews and guides the reader to seminal and continual developments that are the foundations for successful paradigms. It attempts to demystify the abilities and limitations of robots. It is a progress report on the continuing work that will fuel future endeavors. Table of Contents: Part I: Preliminaries/Agency, Motion, and Anatomy/Behaviors / Architectures / Affect/Sensors / Manipulators/Part II: Mobility/Potential Fields/Roadmaps / Reactive Navigation / Multi-Robot Mapping: Brick and Mortar Strategy / Part III: State of the Art / Multi-Robotics Phenomena / Human-Robot Interaction / Fuzzy Control / Decision Theory and Game Theory / Part IV: On the Horizon / Applications: Macro and Micro Robots / References / Author Biography / Discussion
Download or read book Comparison of Hardware and Software Cache Coherence Schemes written by University of Wisconsin--Madison. Computer Sciences Dept and published by . This book was released on 1991 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only cases for which software schemes perform significantly worse than hardware schemes are when there is a greater than 15% reduction in hit rate due to inaccurate prediction of memory access conflicts, or when there are many writes in the program that are not executed at runtime. For relatively well-structured and deterministic programs, on the other hand, software schemes perform significantly better than hardware schemes."
Download or read book Cache Coherence Strategies in a Many core Processor written by Christopher P. Celio and published by . This book was released on 2009 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Caches are frequently employed in memory systems, exploiting memory locality to gain advantages in high-speed performance and low latency. However, as computer processor core counts increase, maintaining coherence between caches becomes increasingly difficult. Current methods of cache coherence work well in small-scale multi-core processors, however, the viability of cache coherence as processors scale to thousands of cores remains an open question. A novel many-core execution-driven performance simulator, called Graphite and implemented by the Carbon group, has been utilized to study a variety of cache coherency strategies of processors up to 256 cores. Results suggest that cache coherence may be possible in future many-core processors, but that software developers will have to exercise great care to match their algorithms to the target architecture to avoid sub-optimal performance.
Download or read book Conference Proceedings written by and published by . This book was released on 1994 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Shared Regions Approach to Software Cache Coherence on Multiprocessors written by Harjinder S. Sandhu and published by . This book was released on 1992 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comparisons with other software based coherence strategies, including a user-controlled strategy and an operating system-based strategy, show that this approach is able to deliver better performance, with relatively low corresponding overhead and only a small increase in the programming effort. Compared to a compiler-based coherence strategy, the Shared Regions approach still performs better than a compiler that can achieve 90% accuracy in allowing cacheing, as long as the regions are a few hundred bytes or larger, or they are re-used a few times in the cache."
Download or read book Architectural Alternatives for Exploiting Parallelism written by David J. Lilja and published by Institute of Electrical & Electronics Engineers(IEEE). This book was released on 1991 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graduates, advanced undergraduates, and practicing engineers of computer architecture or system design, may find interest in the survey of various architectures within which a computer can be induced to walk and chew gum at the same time. The 37 reprinted journal articles and conference presentation
Download or read book Software Cache Coherence for Large Scale Multiprocessors written by University of Rochester. Dept. of Computer Science and published by . This book was released on 1994 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "Shared memory provides an attractive and intuitive programming model that makes good use of programmer time and effort. Shared memory however requires a coherence mechanism to allow caching for performance and to ensure that processors do not use stale data in their caches. We evaluate several algorithmic and architectural alternatives in the design space of NCC-NUMA machines with a globally-accessible physical address space. We present a new adaptive algorithm for software cache coherence that reduces interprocessor communication and scales to large numbers of processors; we compare it to existing software and hardware coherence schemes. We also evaluate (1) the tradeoffs among various write policies (write-through, write-back, write-through with a write-collect buffer) and (2) the effect on performance of using remote memory access. Finally, we observe that certain simple program changes can greatly improve performance. For example, we find that the use of reader-writer locks, synchronization variable relocation, and data structure padding and alignment can allow a protocol to avoid significant amounts of coherence overhead."
Download or read book Evaluating the Performance of Software Cache Coherence written by Susan Owicki and published by . This book was released on 1989 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a shared-memory multiprocessor with private caches, cached copies of a data item must be kept consistent. This is called cache coherence. Both hardware and software coherence schemes have been proposed. Software techniques are attractive because they avoid hardware complexity and can be used with any processor-memory interconnection. This paper presents an analytical model of the performance of two software coherence schemes and, for comparison, snoopy-cache hardware. The model is validated against address traces from a bus-based multiprocessor. The behavior of the coherence schemes under various workloads is compared, and their sensitivity to variations in workload parameters is assessed. The analysis shows that the performance of software schemes is critically determined by certain parameters of the workload: the proportion of data accesses, the fraction of shared references, and the number of times a shared block is accessed before it is purged from the cache. Snoopy caches are more resilient to variations in these parameters. Thus when evaluating a software scheme as a design alternative, it is essential to consider the characteristics of the expected workload. The performance of the two software schemes with a multistage interconnection network is also evaluated, and it is determined that both scale well. Keywords; Computer software, Computer hardware. (kt).
Download or read book The Cache Group Scheme for Hardware controlled Cache Coherence and the General Need for Hardware Coherence Control in Large scale Multiprocessors written by Joseph Edward Hoag and published by . This book was released on 1991 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 1996 ICPP Workshop on Challenges for Parallel Processing August 12 1996 written by Howard Jay Siegel and published by Institute of Electrical & Electronics Engineers(IEEE). This book was released on 1996 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proceedings of the August 1996 workshop are contained in four volumes: v.1, Architecture; v.2, Algorithms and Applications; v.3, Software; and the fourth volume, the proceedings of a workshop connected with the conference, Challenges for Parallel Processing . A total of 270 papers are present
