Download or read book Delay Tolerant Lazy Release Consistency for Distributed Shared Memory in Opportunistic Networks written by Chance Ray Eary and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Opportunistic networking (ON), a concept which allows a mobile wireless device to dynamically interact with other wireless devices in its immediate vicinity, is a field with great potential to improve the utility of itinerant computational platforms. While ONs increase a device's ability to interact with its peers, the fleeting and intermittent connections between devices make many traditional computer collaboration paradigms, such as distributed shared memory (DSM), virtually untenable. DSM systems, developed for traditional networks, rely on relatively stable, consittent connections among participating nodes. In an ON, connectivity among nodes is distributed in time and space making it useful for delay tolerant applications only. When devices are disconnected their ability to collaborate is interrupted and their computing power underutilized until such time as they encounter their computing partners again. Because nodes within an ON are assumed to have no advance knowledge that they will encounter a specific device in the future, periods of disconnection between nodes could be lengthy or potentially infnite. This thesis proposes delay tolerant lazy release consistency (DTLRC) for implementing distributed shared memory in opportunistic networking environments. DTLRC permits mobile devices to remain independently productive while separated and provides a mechanism for nodes to regain coherence of shared memory if and when they meet again. DTLRC allows nodes to make use of results produced on shared memory while disconnected. Simulations using experimentally determined data traces demonstrate that DTLRC is a viable concept for enhancing cooperation among mobile wireless devices in an opportunistic networking environment.
Download or read book Distributed Data Management in Opportunistic Networks written by Chance Ray Eary and published by . This book was released on 2019 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Opportunistic networks (ONs) allow wireless devices, primarily mobile, to interact with one another through a series of opportunistic contacts. While ONs exploit mobility of devices to route messages and distribute information in the absence of dedicated networking infrastructure, the intermittent connections among devices make many traditional computer collaboration paradigms difficult to realize. Two such paradigms are distributed transactions and distributed shared memory (DSM). Distributed transactions are a sequence of operations, executed across multiple nodes, that must successfully complete as specified by its program, or abort with no changes to memory. DSM allows multiple, independent nodes to collectively operate on a pool of memory as if it were a single address space. Originally developed for traditional networks, both paradigms rely on relatively stable, consistent connections among participating nodes to function properly. This dissertation facilitates the employment of distributed transactions and DSM in ONs, by introducing two novel schemes specifically tailored to work in the presence of erratic inter-device connectivity, as well as a thorough investigation into optimizing the latter system to produce the most desirable functionality in a variety of exigent conditions. Distributed Transactions in Opportunistic Networks (DiTON) enables a sequence of operations on shared sets of data, hosted across multiple nodes, while providing global coherency in the event of network interruptions. An implementation of DiTON, and accompanying experimental results, demonstrate that it is possible to utilize transactions in ONs. The second scheme discussed is Delay Tolerant Lazy Release Consistency (DTLRC), a mechanism for implementing distributed shared memory in opportunistic networks. DTLRC permits mobile devices to remain independently productive while separated, and provides a mechanism for nodes to regain coherence of shared memory if and when they meet again. DTLRC allows applications to utilize the most coherent data available, even in challenged environments typical to opportunistic networks. Simulations demonstrate that DTLRC is a viable system for deploying DSM in ONs. Finally, an analytical model for analyzing the behavior of memory in DTLRC is presented. The analytical model provides insights into DTLRC's performance.
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 A Fault Tolerant Distributed Shared Memory System written by Cheryl Kaye DeMatteis and published by . This book was released on 1996 with total page 350 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 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 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 Shared Memory Consistency Models written by Abdul Naeem and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: The shared memory systems should support parallelization at the computation (multiprocessor), communication (Network-on-Chip, NoC) and memory architecture levels to exploit the potential performance benefits. Such systems are facing the critical issues of memory consistency and coherence. Memory consistency issue arises due to the unconstrained operations which sometimes lead to the unexpected behavior of the systems. Memory consistency models are used to resolve this issue. Relaxed or weaker consistency models enforce less ordering constraints on the memory operations and exploit system optimizations compared to the stricter models. This book discusses the novel realization schemes and scalability analysis of strict Sequential Consistency (SC) model and relaxed memory consistency models: Total Store Ordering (TSO), Partial Store Ordering (PSO), Weak Ordering (WO), Release Consistency (RC), and Protected Release Consistency (PRC) in the NoC based distributed shared memory multiprocessor systems. This study should help the average readers and professionals to understand the critical issue of memory consistency both in the NoC based systems and general purpose multiprocessor systems.
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 Distributed Computing written by Ajay D. Kshemkalyani and published by Cambridge University Press. This book was released on 2011-03-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designing distributed computing systems is a complex process requiring a solid understanding of the design problems and the theoretical and practical aspects of their solutions. This comprehensive textbook covers the fundamental principles and models underlying the theory, algorithms and systems aspects of distributed computing. Broad and detailed coverage of the theory is balanced with practical systems-related issues such as mutual exclusion, deadlock detection, authentication, and failure recovery. Algorithms are carefully selected, lucidly presented, and described without complex proofs. Simple explanations and illustrations are used to elucidate the algorithms. Important emerging topics such as peer-to-peer networks and network security are also considered. With vital algorithms, numerous illustrations, examples and homework problems, this textbook is suitable for advanced undergraduate and graduate students of electrical and computer engineering and computer science. Practitioners in data networking and sensor networks will also find this a valuable resource. Additional resources are available online at www.cambridge.org/9780521876346.
Download or read book Computer Organization and Design RISC V Edition written by David A. Patterson and published by Morgan Kaufmann. This book was released on 2017-05-12 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: The new RISC-V Edition of Computer Organization and Design features the RISC-V open source instruction set architecture, the first open source architecture designed to be used in modern computing environments such as cloud computing, mobile devices, and other embedded systems. With the post-PC era now upon us, Computer Organization and Design moves forward to explore this generational change with examples, exercises, and material highlighting the emergence of mobile computing and the Cloud. Updated content featuring tablet computers, Cloud infrastructure, and the x86 (cloud computing) and ARM (mobile computing devices) architectures is included. An online companion Web site provides advanced content for further study, appendices, glossary, references, and recommended reading. - Features RISC-V, the first such architecture designed to be used in modern computing environments, such as cloud computing, mobile devices, and other embedded systems - Includes relevant examples, exercises, and material highlighting the emergence of mobile computing and the cloud
Download or read book Fault Tolerant Computer Architecture written by Daniel Sorin and published by Morgan & Claypool Publishers. This book was released on 2009-07-08 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: For many years, most computer architects have pursued one primary goal: performance. Architects have translated the ever-increasing abundance of ever-faster transistors provided by Moore's law into remarkable increases in performance. Recently, however, the bounty provided by Moore's law has been accompanied by several challenges that have arisen as devices have become smaller, including a decrease in dependability due to physical faults. In this book, we focus on the dependability challenge and the fault tolerance solutions that architects are developing to overcome it. The two main purposes of this book are to explore the key ideas in fault-tolerant computer architecture and to present the current state-of-the-art - over approximately the past 10 years - in academia and industry. Table of Contents: Introduction / Error Detection / Error Recovery / Diagnosis / Self-Repair / The Future
Download or read book Building Secure and Reliable Network Applications written by Kenneth P. Birman and published by Prentice Hall. This book was released on 1996 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computer Organization and Design written by John L. Hennessy and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introducing Intercultural Communication written by Shuang Liu and published by SAGE. This book was released on 2010-11-09 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Books on intercultural communication are rarely written with an intercultural readership in mind. In contrast, this multinational team of authors has put together an introduction to communicating across cultures that uses examples and case studies from around the world. The book further covers essential new topics, including international conflict, social networking, migration, and the effects technology and mass media play in the globalization of communication. Written to be accessible for international students too, this text situates communication theory in a truly global perspective. Each chapter brings to life the links between theory and practice and between the global and the local, introducing key theories and their practical applications. Along the way, you will be supported with first-rate learning resources, including: • theory corners with concise, boxed-out digests of key theoretical concepts • case illustrations putting the main points of each chapter into context • learning objectives, discussion questions, key terms and further reading framing each chapter and stimulating further discussion • a companion website containing resources for instructors, including multiple choice questions, presentation slides, exercises and activities, and teaching notes. This book will not merely guide you to success in your studies, but will teach you to become a more critical consumer of information and understand the influence of your own culture on how you view yourself and others.
Download or read book Applying UML and Patterns An Introduction to Object Oriented Analysis and Design and Interative Development 3rd Edition written by Craig Larman and published by Pearson Education India. This book was released on 2012 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Epistemologies of the South written by Boaventura de Sousa Santos and published by Routledge. This book was released on 2015-11-17 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the concept of 'cognitive injustice': the failure to recognise the different ways of knowing by which people across the globe run their lives and provide meaning to their existence. Boaventura de Sousa Santos shows why global social justice is not possible without global cognitive justice. Santos argues that Western domination has profoundly marginalised knowledge and wisdom that had been in existence in the global South. She contends that today it is imperative to recover and valorize the epistemological diversity of the world. Epistemologies of the South outlines a new kind of bottom-up cosmopolitanism, in which conviviality, solidarity and life triumph against the logic of market-ridden greed and individualism.
