Zusammenfassung: This book offers a comprehensive survey of shared-memory synchronization, with an emphasis on "systems-level" issues. It includes sufficient coverage of architectural details to understand correctness and performance on modern multicore machines, and sufficient coverage of higher-level issues to understand how synchronization is embedded in modern programming languages. The primary intended audience for this book is "systems programmers"--the authors of operating systems, library packages, language run-time systems, concurrent data structures, and server and utility programs. Much of the discussion should also be of interest to application programmers who want to make good use of the synchronization mechanisms available to them, and to computer architects who want to understand the ramifications of their design decisions on systems-level code

Excerpt from Efficient Synchronization on Multiprocessors With Shared Memory Shared memory provides convenient communication between processes in a tightly coupled multiprocessing system. Shared variables can be used for data sharing, information transfer between processes, and, in particular, for coordination and synchronization. Constructs such as the semaphore introduced by Dijkstra inDi, and the many variants that followed, provide convenient solutions to many synchronization problems involving arbitrary number of processes. These constructs are supported in hardware by machine instructions that atomically execute a Read-Modify-Write cycle. Such instructions exist on most modern CPUs. An atomic Read-Modify-Write operation only requires that it be semantically atomic, although it is often processed atomically also. The serial bottleneck created by this atomic processing, while acceptable for small scale parallelism, can seriously impair the performance of a system with thousands of processors. Frequent accesses to a shared variable not only slow down those processes performing the access, but may cause the entire machine to thrash. Large-scale shared memory parallel processors are likely to use multistage packet switched interconnection networks for processor to memory traffic. These networks provide high bandwidth and short latency time when memory accesses are distributed randomly, but, if even a small percentage of the memory requests are directed to one specific spot, the network becomes congested and performance quickly degrades. A recent study of Pfister and Norton Pn shows that not only those processors attempting to access the same hot spot are delayed, but also the remaining processors. Although replication of data can often be used to circumvent the hot spot problem for read-only data, it cannot be used for synchronization variables. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The workshop on Scalable Shared Memory Multiprocessors took place on May 26 and 27 1990 at the Stouffer Madison Hotel in Seattle, Washington as a prelude to the 1990 International Symposium on Computer Architecture. About 100 participants listened for two days to the presentations of 22 invited The motivation for this workshop was to speakers, from academia and industry. promote the free exchange of ideas among researchers working on shared-memory multiprocessor architectures. There was ample opportunity to argue with speakers, and certainly participants did not refrain a bit from doing so. Clearly, the problem of scalability in shared-memory multiprocessors is still a wide-open question. We were even unable to agree on a definition of "scalability". Authors had more than six months to prepare their manuscript, and therefore the papers included in this proceedings are refinements of the speakers' presentations, based on the criticisms received at the workshop. As a result, 17 authors contributed to these proceedings. We wish to thank them for their diligence and care. The contributions in these proceedings can be partitioned into four categories 1. Access Order and Synchronization 2. Performance 3. Cache Protocols and Architectures 4. Distributed Shared Memory Particular topics on which new ideas and results are presented in these proceedings include: efficient schemes for combining networks, formal specification of shared memory models, correctness of trace-driven simulations,synchronization, various coherence protocols, .

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.

Dr. Lenoski and Dr. Weber have experience with leading-edge research and practical issues involved in implementing large-scale parallel systems. They were key contributors to the architecture and design of the DASH multiprocessor. Currently, they are involved with commercializing scalable shared-memory technology.

Aging population and the thereby ever-rising cost of health services call for novel and innovative solutions for providing medical care and services. So far, medical care is primarily provided in the form of time-consuming in-person appointments with trained personnel and expensive, stationary instrumentation equipment. As for many current and past challenges, the advances in microelectronics are a crucial enabler and offer a plethora of opportunities. With key building blocks such as sensing, processing, and communication systems and circuits getting smaller, cheaper, and more energy-efficient, personal and wearable or even implantable point-of-care devices with medicalgrade instrumentation capabilities become feasible. Device size and battery lifetime are paramount for the realization of such devices. Besides integrating the required functionality into as few individual microelectronic components as possible, the energy efficiency of such is crucial to reduce battery size, usually being the dominant contributor to overall device size. In this thesis, we present two major contributions to achieve the discussed goals in the context of miniaturized medical instrumentation: First, we present a synchronization solution for embedded, parallel near-threshold computing (NTC), a promising concept for enabling the required processing capabilities with an energy efficiency that is suitable for highly mobile devices with very limited battery capacity. Our proposed solution aims at increasing energy efficiency and performance for parallel NTC clusters by maximizing the effective utilization of the available cores under parallel workloads. We describe a hardware unit that enables fine-grain parallelization by greatly optimizing and accelerating core-to-core synchronization and communication and analyze the impact of those mechanisms on the overall performance and energy efficiency of an eight-core cluster. With a range of digital signal processing (DSP) applications typical for the targeted systems, the proposed hardware unit improves performance by up to 92% and 23% on average and energy efficiency by up to 98% and 39% on average. In the second part, we present a MCU processing and control subsystem (MPCS) for the integration into VivoSoC, a highly versatile single-chip solution for mobile medical instrumentation. In addition to the MPCS, it includes a multitude of analog front-ends (AFEs) and a multi-channel power management IC (PMIC) for voltage conversion. ...

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

The Art of Multiprocessor Programming, Second Edition, provides users with an authoritative guide to multicore programming. This updated edition introduces higher level software development skills relative to those needed for efficient single-core programming, and includes comprehensive coverage of the new principles, algorithms, and tools necessary for effective multiprocessor programming. The book is an ideal resource for students and professionals alike who will benefit from its thorough coverage of key multiprocessor programming issues. - Features new exercises developed for instructors using the text, with more algorithms, new examples, and other updates throughout the book - Presents the fundamentals of programming multiple threads for accessing shared memory - Explores mainstream concurrent data structures and the key elements of their design, as well as synchronization techniques, from simple locks to transactional memory systems