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.

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."

Abstract: "Recent distributed shared memory (DSM) systems and proposed shared-memory machines have implemented some or all of their cache coherence protocols in software. One way to exploit the flexibility of this software is to tailor a coherence protocol to match an application's communication patterns and memory semantics. This paper presents evidence that this approach can lead to large performance improvements. It shows that application-specific protocols substantially improved the performance of three application programs -- appbt, em3d, and barnes -- over carefully tuned transparent shared memory implementations. The speed-ups were obtained on Blizzard, a fine-grained DSM system running on a 32-node Thinking Machines CM-5."

This book constitutes the strictly refereed post-workshop proceedings of the 5th International Workshop on Languages, Compilers, and Run-Time Systems for Scalable Computing, LCR 2000, held in Rochester, NY, USA in May 2000. The 22 revised full papers presented were carefully reviewed and selected from 38 submissions. The papers are organized in topical sections on data-intensive computing, static analysis, openMP support, synchronization, software DSM, heterogeneous/-meta-computing, issues of load, and compiler-supported parallelism.