Download or read book Lazy consistency for software distributed shared memory written by Pete Keleher and published by . This book was released on 1991 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lazy Release Consistency for Software Distributed Shared Memory written by Rice University. Dept. of Computer Science and published by . This book was released on 1991 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: These reductions are especially significant for programs that exhibit false sharing and make extensive use of locks."
Download or read book Lazy Release Consistency for Distributed Shared Memory written by Rice University. Dept. of Computer Science and published by . This book was released on 1995 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "A software distributed shared memory (DSM) system allows shared memory parallel programs to execute on networks of workstations. This thesis presents a new class of protocols that has lower communication requirements than previous DSM protocols, and can consequently achieve higher performance. The lazy release consistent protocols achieve this reduction in communication by piggybacking consistency information on top of existing synchronization transfers. Some of the protocols also improve performance by speculatively moving data. We evaluate the impact of these features by comparing the performance of a software DSM using lazy protocols with that of a DSM using previous eager protocols. We found that seven of our eight applications performed better on the lazy system, and four of the applications showed performance speedups of at least 18%. As part of this comparison, we show that the cost of executing the slightly more complex code of the lazy protocols is far less important than the reduction in communication requirements. We also compare the lazy performance with that of a hardware supported shared memory system that uses processors and caches similar to those of the workstations running our DSM. Our DSM system was able to approach, and in one case even surpass, the performance of the hardware system for applications with coarse-grained parallelism, but the hardware system performed significantly better for programs with fine-grained parallelism. Overall, the results indicate that DSMs using lazy protocols have become a viable alternative for high-performance parallel processing."
Download or read book Support for Software Distributed Shared Memory on Clusters of Heterogeneous Workstations written by Subhabrata Saha and published by . This book was released on 2002 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Distributed Shared Memory written by Jelica Protic and published by John Wiley & Sons. This book was released on 1997-08-10 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers present in this text survey both distributed shared memory (DSM) efforts and commercial DSM systems. The book discusses relevant issues that make the concept of DSM one of the most attractive approaches for building large-scale, high-performance multiprocessor systems. The authors provide a general introduction to the DSM field as well as a broad survey of the basic DSM concepts, mechanisms, design issues, and systems. The book concentrates on basic DSM algorithms, their enhancements, and their performance evaluation. In addition, it details implementations that employ DSM solutions at the software and the hardware level. This guide is a research and development reference that provides state-of-the art information that will be useful to architects, designers, and programmers of DSM systems.
Download or read book Relaxing Consistency in Recoverable Distributed Shared Memory written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Relaxed memory consistency models tolerate increased memory access latency in both hardware and software distributed shared memory systems. In recoverable systems, relaxing consistency has the added benefit of reducing the number of checkpoints needed to avoid rollback propagation. In this paper, we introduce new checkpointing algorithms that take advantage of relaxed consistency to reduce the performance overhead of checkpointing. We also introduce a scheme based on lazy relaxed consistency, that reduces both checkpointing overhead and the overhead of avoiding error propagation in systems with error latency. We use multiprocessor address traces to evaluate the relaxed consistency approach to checkpointing with distributed shared memory.
Download or read book Aggressive Release Consistency and Efficient Lock Implementation for Software Distributed Shared Memory written by Shiwa S. Fu and published by . This book was released on 1997 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lazy Release Consistency for Hardware coherent Multiprocessors written by University of Rochester. Dept. of Computer Science and published by . This book was released on 1994 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "Release consistency is a widely accepted memory model for distributed shared memory systems. It provides significant opportunities for a coherence protocol to improve performance by delaying and buffering coherence operations. Different protocol implementations exploit these opportunities to different extents. Eager release consistency represents the state of the art for hardware-coherent multiprocessors, while lazy release consistency has been shown to provide better performance for software distributed shared memory (DSM). Several of the optimizations performed by lazy protocols have the potential to improve the performance of hardware-coherent multiprocessors, but their complexity has precluded a hardware implementation. With the advent of programmable protocol processors it may become possible to use them after all. We present and evaluate a lazy release-consistent protocol suitable for machines with dedicated protocol processors. This protocol admits multiple concurrent writers, sends write notices concurrently with computation, and delays invalidations until acquire operations. We also consider a lazier protocol that delays sending write notices until release operations. Our results indicate that the first protocol outperforms eager release consistency by as much as 20% across a variety of applications. The lazier protocol, on the other hand, is unable to recoup its high synchronization overhead. This represents a qualitative shift from the DSM world, where lazier protocols always yield performance improvements. We also study protocol performance under a variety of architectural settings and show that the performance gap between lazy and eager implementations of release consistency will increase on future machines. Based on our results, we conclude that machines with flexible hardware support for coherence should use protocols based on lazy release consistency, but in a less 'aggressively lazy' form than is appropriate for DSM."
Download or read book Consistent Distributed Storage written by Vincent Gramoli and published by Springer Nature. This book was released on 2022-05-31 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing a shared memory abstraction in distributed systems is a powerful tool that can simplify the design and implementation of software systems for networked platforms. This enables the system designers to work with abstract readable and writable objects without the need to deal with the complexity and dynamism of the underlying platform. The key property of shared memory implementations is the consistency guarantee that it provides under concurrent access to the shared objects. The most intuitive memory consistency model is atomicity because of its equivalence with a memory system where accesses occur serially, one at a time. Emulations of shared atomic memory in distributed systems is an active area of research and development. The problem proves to be challenging, and especially so in distributed message passing settings with unreliable components, as is often the case in networked systems. We present several approaches to implementing shared memory services with the help of replication on top of message-passing distributed platforms subject to a variety of perturbations in the computing medium.
Download or read book Eureka written by Joao Alberto Vianna Tavares and published by . This book was released on 1995 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Distributed Shared Memory (DSM) provides an abstraction of shared memory on a network of workstations. Problems with existing DSM systems are lack of portability due to compiler and/or operating system modification requirements, and reduced performance due to significant synchronization and communication costs when compared to their message passing counterparts (e.g., PVM and MPI). Our approach was to introduce a new DSM consistency model, Lazy Data Merging (LDM), which extends Data Merging (DM). LDM is optimized for software runtime implementations and differs from DM by 'lazily' placing data updates across the communication network only when they are required. It is our belief that LDM can significantly reduce communication costs, particularly for applications that make extensive use of locks. We have completed the design of "Eureka", a prototype DSM system that provides a software implementation of the LDM consistency model. To ensure portability and efficiency we use only standard UniXTM system calls and a publicly available software thread package, Cthreads, from the University of Utah. Furthermore, we have implemented and tested some of Eureka's core components, specifically, the set of communication and hybrid (Invalidate/Update) coherence primitives, which are essential for follow on work in building the complete DSM system. The question of efficiency is still an open problem, because we did not compare Eureka with other DSM implementations.
Download or read book Eureka written by Joao Alberto Vianna Tavares and published by . This book was released on 1995 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Distributed Shared Memory (DSM) provides an abstraction of shared memory on a network of workstations. Problems with existing DSM systems are lack of portability due to compiler and/or operating system modification requirements, and reduced performance due to significant synchronization and communication costs when compared to their message passing counterparts (e.g., PVM and MPI). Our approach was to introduce a new DSM consistency model, Lazy Data Merging (LDM), which extends Data Merging (DM). LDM is optimized for software runtime implementations and differs from DM by 'lazily' placing data updates across the communication network only when they are required. It is our belief that LDM can significantly reduce communication costs, particularly for applications that make extensive use of locks. We have completed the design of "Eureka", a prototype DSM system that provides a software implementation of the LDM consistency model. To ensure portability and efficiency we use only standard UniXTM system calls and a publicly available software thread package, Cthreads, from the University of Utah. Furthermore, we have implemented and tested some of Eureka's core components, specifically, the set of communication and hybrid (Invalidate/Update) coherence primitives, which are essential for follow on work in building the complete DSM system. The question of efficiency is still an open problem, because we did not compare Eureka with other DSM implementations.
Download or read book Detecting Data Races in Software Distributed Shared Memory written by Rice University. Dept. of Computer Science and published by . This book was released on 1991 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use this fact to claim an optimistic approach to guaranteeing consistency will rarely have to backtrack. Valkyrie will detect consistency violations during runtime and roll back offending computations. Valkyrie's optimistic nature allows us to tailor the underlying memory consistency protocol to a form of weak memory that best matches the target application. Valkyrie will therefore be able to deliver the performance of a weakly consistent system while retaining the simple programming model of a strongly consistent system."
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 Handbook of Parallel Computing written by Sanguthevar Rajasekaran and published by CRC Press. This book was released on 2007-12-20 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability of parallel computing to process large data sets and handle time-consuming operations has resulted in unprecedented advances in biological and scientific computing, modeling, and simulations. Exploring these recent developments, the Handbook of Parallel Computing: Models, Algorithms, and Applications provides comprehensive coverage on a
Download or read book Innovative Internet Computing Systems written by Thomas Böhme and published by Springer. This book was released on 2003-05-15 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, the Internet is the most commonly used medium for the exchange of data in di?erent forms. Presently, over 60 million machines have access to the Internet and to its resources. However, the Internet is also the largest distributed system o?ering di?erent computational services and possibilities not only for cluster computing. If the needs of modern mobile computing and multimedia systems are taken into account, it becomes clear that modern methods must ensure an e?ective development and management of the Internet allowing each user fast access to this huge resource space. The Innovative Internet Computing Systems workshop is organized by the Gesellschaft fur ̈ Informatik(GI) in Germany. It intends to be an open me- ing point for scientists dealing with di?erent aspects of this complex topic. In contrast to the Distributed Communities on the Web workshops, which can be 2 considered as the roots of I CS, special attention is given to fundamental - search works and the application of theoretical and formal results in practical implementations.
Download or read book Languages Compilers and Run Time Systems for Scalable Computers written by David O'Hallaron and published by Springer. This book was released on 2003-06-29 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the strictly refereed post-workshop proceedings of the 4th International Workshop on Languages, Compilers, and Run-Time Systems for Scalable Computing, LCR '98, held in Pittsburgh, PA, USA in May 1998. The 23 revised full papers presented were carefully selected from a total of 47 submissions; also included are nine refereed short papers. All current issues of developing software systems for parallel and distributed computers are covered, in particular irregular applications, automatic parallelization, run-time parallelization, load balancing, message-passing systems, parallelizing compilers, shared memory systems, client server applications, etc.
