Static scheduling of a program represented by a directed task graph on a multiprocessor system to minimize the program completion time is a well-known problem in parallel processing. Since finding an optimal schedule is an NP-complete problem in general, researchers have resorted to devising efficient heuristics. A plethora of heuristics have been proposed based on a wide spectrum of techniques, including branch-and-bound, integer-programming, searching, graph-theory, randomization, genetic algorithms, and evolutionary methods. The objective of this survey is to describe various scheduling algorithms and their functionalities in a contrasting fashion as well as examine their relative merits in terms of performance and time-complexity. Since these algorithms are based on diverse assumptions, they differ in their functionalities, and hence are difficult to describe in a unified context. We propose a taxonomy that classifies these algorithms into different categories. We consider 27 scheduling algorithms, with each algorithm explained through an easy-to-understand description followed by an illustrative example to demonstrate its operation. We also outline some of the novel and promising optimization approaches and current research trends in the area. Finally, we give an overview of the software tools that provide scheduling/mapping functionalities.

http://charm.cs.uiuc.edu/users/arya/docs/6.pdf

Static scheduling algorithms for allocating directed task graphs to multiprocessors

Programming assistance, automation concepts, and their application to a message-passing system program development tool called Hypertool are discussed. Hypertool performs scheduling and handles the communication primitive insertion automatically, thereby increasing productivity and eliminating synchronization errors. Two algorithms, based on the critical-path method, are presented for scheduling processes statically. Hypertool also generates the performance estimates and other program quality measures to help programmers improve their algorithms and programs. >

Hypertool: a programming aid for message-passing systems

The paper surveys a decade of R&D on coarse grain reconfigurable hardware and related CAD, points out why this emerging discipline is heading toward a dichotomy of computing science, and advocates the introduction of a new soft machine paradigm to replace CAD by compilation.

A decade of reconfigurable computing: a visionary retrospective

High-level synthesis systems start with an abstract behavioral specification of a digital system and find a register-transfer level structure that realizes the given behavior. The various tasks involved in developing a register-transfer level structure from an algorithmic level specification are described. In particular, it is shown how the high-level synthesis task can be decomposed into a number of distinct but not independent subtasks. The techniques that have been developed for solving those subtasks are presented. Areas related to high-level synthesis that are still open problems are examined. >

The high-level synthesis of digital systems

The constantly increasing demand for more computing power can seem impossible to keep up with. However, multicore processors capable of performing computations in parallel allow computers to tackle ever larger problems in a wide variety of applications. This book provides a comprehensive introduction to parallel computing, discussing theoretical issues such as the fundamentals of concurrent processes, models of parallel and distributed computing, and metrics for evaluating and comparing parallel algorithms, as well as practical issues, including methods of designing and implementing shared- and distributed-memory programs, and standards for parallel program implementation, in particular MPI and OpenMP interfaces. Each chapter presents the basics in one place followed by advanced topics, allowing novices and experienced practitioners to quickly find what they need. A glossary and more than 80 exercises with selected solutions aid comprehension. The book is recommended as a text for advanced undergraduate or graduate students and as a reference for practitioners.

Introduction to Parallel Computing

This special issue is about the methodologies and tools that may help us solve the VLSI design crisis of the 1980s. Basically, there are three approaches. The first school of thought believes that all design decisions should be made solely by the human designer, who has gained experience through good design practices in the last 10 or 20 years. This approach, called computeraided design, gives the designer an "efficient paper and pencil" by providing graphic editors, design verification and simulation tools, and efficient databases. This approach is evolutionary and tends to be bottom up, since building blocks are first designed and then later used to realize higher level structures. The resulting design is of high quality, since humans are very good in optimizing designs. On the other hand, the human designer is slow and error-prone. Furthermore, creative designers optimize design by creating new design rules, thereby creating a demand for new verification tools and design description languages for documentation and communication between designers. After a bried review of the three approaches, the collection of articles presented, depicting all three approaches to VLSI design tools (each representing a different methodology in VLSI design), are briefly summarized.

Guest Editors' Introduction: New VLSI Tools

The authors argue that due to their simplicity and strong appeal to intuition, data flow techniques attract a great deal of attention. Other alternatives, however, offer more hope for the future. 25 references.

A Second Opinion on Data Flow Machines and Languages

During the past several years, a great number of proposals have been made with the objective to increase supercomputer performance by an order of magnitude on the basis of a utilization of new computer architectures. The present paper is concerned with a suitable classification scheme for comparing these architectures. It is pointed out that there are basically four schools of thought as to the most important factor for an enhancement of computer performance. According to one school, the development of faster circuits will make it possible to retain present architectures, except, possibly, for a mechanism providing synchronization of parallel processes. A second school assigns priority to the optimization and vectorization of compilers, which will detect parallelism and help users to write better parallel programs. A third school believes in the predominant importance of new parallel algorithms, while the fourth school supports new models of computation. The merits of the four approaches are critically evaluated. 50 references.

Gajski

Papers

Guest Editors' Introduction: New VLSI Tools

A Second Opinion on Data Flow Machines and Languages

Essential Issues in Multiprocessor Systems