Introduction to Concurrency in Programming Languages

346 Pages·2009·6.381 MB·

by  Mattson, Timothy G., Rasmussen, Craig E., Sottile, Matthew J

INTRODUCTION TO
Concurrency in
Programming
Languages
8/19/09 10:02:40 AM
Chapman & Hall/CRC
Computational Science Series
SERIES EDITOR
Horst Simon
Associate Laboratory Director, Computing Sciences
Lawrence Berkeley National Laboratory
Berkeley, California, U.S.A.
AIMS AND SCOPE
This series aims to capture new developments and applications in the field of computational sci-
ence through the publication of a broad range of textbooks, reference works, and handbooks.
Books in this series will provide introductory as well as advanced material on mathematical, sta-
tistical, and computational methods and techniques, and will present researchers with the latest
theories and experimentation. The scope of the series includes, but is not limited to, titles in the
areas of scientific computing, parallel and distributed computing, high performance computing,
grid computing, cluster computing, heterogeneous computing, quantum computing, and their
applications in scientific disciplines such as astrophysics, aeronautics, biology, chemistry, climate
modeling, combustion, cosmology, earthquake prediction, imaging, materials, neuroscience, oil
exploration, and weather forecasting.
PUBLISHED TITLES
PETASCALE COMPUTING: Algorithms and Applications
Edited by David A. Bader
PROCESS ALGEBRA FOR PARALLEL AND DISTRIBUTED PROCESSING
Edited by Michael Alexander and William Gardner
GRID COMPUTING: TECHNIQUES AND APPLICATIONS
Barry Wilkinson
INTRODUCTION TO CONCURRENCY IN PROGRAMMING LANGUAGES
Matthew J. Sottile, Timothy G. Mattson, and Craig E Rasmussen
C7213_FM.indd 2 8/19/09 10:02:40 AM
I N T RO D U C T I O N T O
Concurrency in
Programming
Languages
M J. S
atthew ottile
t G. M
iMothy attSon
C e r
raiG aSMuSSen
C7213_FM.indd 3 8/19/09 10:02:40 AM
MATLAB® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not
warrant the accuracy of the text or exercises in this book. This book’s use or discussion of MATLAB® soft-
ware or related products does not constitute endorsement or sponsorship by The MathWorks of a particular
pedagogical approach or particular use of the MATLAB® software.
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2009 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Version Date: 20131120
International Standard Book Number-13: 978-1-4200-7214-3 (eBook - PDF)
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts
have been made to publish reliable data and information, but the author and publisher cannot assume
responsibility for the validity of all materials or the consequences of their use. The authors and publishers
have attempted to trace the copyright holders of all material reproduced in this publication and apologize to
copyright holders if permission to publish in this form has not been obtained. If any copyright material has
not been acknowledged please write and let us know so we may rectify in any future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmit-
ted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented,
including photocopying, microfilming, and recording, or in any information storage or retrieval system,
without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.
com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood
Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and
registration for a variety of users. For organizations that have been granted a photocopy license by the CCC,
a separate system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used
only for identification and explanation without intent to infringe.
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com
Matthew J. Sottile and Timothy G. Mattson and Craig E Rasmussen
Introduction to
Concurrency in
Programming Languages
CRC PRESS
Boca Raton London New York Washington, D.C.

Contents
1 Introduction 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1 Navigating the concurrency sea . . . . . . . . . . . . . 3
1.2 Where does concurrency appear? . . . . . . . . . . . . . . . 6
1.3 Why is concurrency considered hard? . . . . . . . . . . . . . 9
1.3.1 Real-world concurrency . . . . . . . . . . . . . . . . . 9
1.4 Timeliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.5 Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.5.1 Intended audience . . . . . . . . . . . . . . . . . . . . 13
1.5.2 Acknowledgments . . . . . . . . . . . . . . . . . . . . 14
1.6 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2 Concepts in Concurrency 17
2.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.1.1 Units of execution . . . . . . . . . . . . . . . . . . . . 19
2.1.2 Parallelism versus concurrency . . . . . . . . . . . . . 23
2.1.3 Dependencies and parallelism . . . . . . . . . . . . . . 25
2.1.4 Shared versus distributed memory . . . . . . . . . . . 28
2.2 Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.2.1 Atomicity . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.2.2 Mutual exclusion and critical sections . . . . . . . . . 34
2.2.3 Coherence and consistency . . . . . . . . . . . . . . . 36
2.2.4 Thread safety . . . . . . . . . . . . . . . . . . . . . . . 38
2.3 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3 Concurrency Control 43
3.1 Correctness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.1.1 Race conditions . . . . . . . . . . . . . . . . . . . . . . 44
3.1.2 Deadlock . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.1.3 Liveness, starvation and fairness . . . . . . . . . . . . 49
3.1.4 Nondeterminism . . . . . . . . . . . . . . . . . . . . . 51
3.2 Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.2.1 Synchronization . . . . . . . . . . . . . . . . . . . . . 52
3.2.2 Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.2.3 Semaphores . . . . . . . . . . . . . . . . . . . . . . . . 56
3.2.4 Monitors . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.2.5 Transactions . . . . . . . . . . . . . . . . . . . . . . . 60
v
vi Contents
3.3 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4 The State of the Art 65
4.1 Limitations of libraries . . . . . . . . . . . . . . . . . . . . . 66
4.2 Explicit techniques . . . . . . . . . . . . . . . . . . . . . . . 69
4.2.1 Message passing . . . . . . . . . . . . . . . . . . . . . 69
4.2.2 Explicitly controlled threads. . . . . . . . . . . . . . . 75
4.3 Higher-level techniques . . . . . . . . . . . . . . . . . . . . . 76
4.3.1 Transactional memory . . . . . . . . . . . . . . . . . . 77
4.3.2 Event-driven programs . . . . . . . . . . . . . . . . . . 78
4.3.3 The Actor model . . . . . . . . . . . . . . . . . . . . . 79
4.4 The limits of explicit control . . . . . . . . . . . . . . . . . . 80
4.4.1 Pointers and aliasing . . . . . . . . . . . . . . . . . . . 81
4.5 Concluding remarks . . . . . . . . . . . . . . . . . . . . . . . 82
4.6 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5 High-Level Language Constructs 85
5.1 Common high-level constructs . . . . . . . . . . . . . . . . . 88
5.1.1 Expressions . . . . . . . . . . . . . . . . . . . . . . . . 89
5.1.2 Control flow primitives. . . . . . . . . . . . . . . . . . 91
5.1.3 Abstract types and data structures . . . . . . . . . . . 92
5.2 Using and evaluating language constructs . . . . . . . . . . . 94
5.2.1 Cognitive dimensions. . . . . . . . . . . . . . . . . . . 98
5.2.2 Working with the cognitive dimensions . . . . . . . . . 101
5.3 Implications of concurrency . . . . . . . . . . . . . . . . . . . 102
5.3.1 Sequential constructs and concurrency . . . . . . . . . 103
5.4 Interpreted languages . . . . . . . . . . . . . . . . . . . . . . 104
5.5 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
6 Historical Context and Evolution of Languages 109
6.1 Evolution of machines . . . . . . . . . . . . . . . . . . . . . . 111
6.1.1 Multiprogramming and interrupt driven I/O . . . . . 111
6.1.2 Cache-based memory hierarchies . . . . . . . . . . . . 112
6.1.3 Pipelining and vector processing . . . . . . . . . . . . 113
6.1.4 Dataflow . . . . . . . . . . . . . . . . . . . . . . . . . 114
6.1.5 Massively parallel computers . . . . . . . . . . . . . . 115
6.1.6 Clusters and distributed memory systems . . . . . . . 117
6.1.7 Integration . . . . . . . . . . . . . . . . . . . . . . . . 118
6.1.8 Flynn’s taxonomy . . . . . . . . . . . . . . . . . . . . 118
6.2 Evolution of programming languages . . . . . . . . . . . . . 120
6.2.1 In the beginning, there was FORTRAN . . . . . . . . 120
6.2.2 The ALGOL family . . . . . . . . . . . . . . . . . . . 122
6.2.3 Coroutines . . . . . . . . . . . . . . . . . . . . . . . . 125
6.2.4 CSP and process algebras . . . . . . . . . . . . . . . . 125
6.2.5 Concurrency in Ada . . . . . . . . . . . . . . . . . . . 128
Contents vii
6.2.6 Declarative and functional languages . . . . . . . . . . 131
6.2.7 Parallel languages . . . . . . . . . . . . . . . . . . . . 138
6.2.8 Modern languages . . . . . . . . . . . . . . . . . . . . 144
6.3 Limits to automatic parallelization . . . . . . . . . . . . . . . 145
6.4 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
7 Modern Languages and Concurrency Constructs 149
7.1 Array abstractions . . . . . . . . . . . . . . . . . . . . . . . . 150
7.1.1 Array notation . . . . . . . . . . . . . . . . . . . . . . 152
7.1.2 Shifts . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
7.1.3 Index sets and regions . . . . . . . . . . . . . . . . . . 157
7.2 Message passing . . . . . . . . . . . . . . . . . . . . . . . . . 158
7.2.1 The Actor model . . . . . . . . . . . . . . . . . . . . . 160
7.2.2 Channels . . . . . . . . . . . . . . . . . . . . . . . . . 160
7.2.3 Co-arrays . . . . . . . . . . . . . . . . . . . . . . . . . 161
7.3 Control flow . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
7.3.1 ALGOL collateral clauses . . . . . . . . . . . . . . . . 163
7.3.2 PAR, SEQ and ALT in occam . . . . . . . . . . . . . 164
7.3.3 Parallel loops . . . . . . . . . . . . . . . . . . . . . . . 166
7.4 Functional languages . . . . . . . . . . . . . . . . . . . . . . 168
7.5 Functional operators . . . . . . . . . . . . . . . . . . . . . . . 169
7.5.1 Discussion of functional operators . . . . . . . . . . . 171
7.6 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
8 Performance Considerations and Modern Systems 175
8.1 Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
8.1.1 Architectural solutions to the performance problem. . 177
8.1.2 Examining single threaded memory performance . . . 178
8.1.3 Shared memory and cache coherence . . . . . . . . . . 180
8.1.4 Distributed memory as a deeper memory hierarchy . . 185
8.2 Amdahl’s law, speedup, and efficiency . . . . . . . . . . . . . 186
8.3 Locking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
8.3.1 Serialization . . . . . . . . . . . . . . . . . . . . . . . . 188
8.3.2 Blocking . . . . . . . . . . . . . . . . . . . . . . . . . . 189
8.3.3 Wasted operations . . . . . . . . . . . . . . . . . . . . 190
8.4 Thread overhead . . . . . . . . . . . . . . . . . . . . . . . . . 191
8.5 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
9 Introduction to Parallel Algorithms 197
9.1 Designing parallel algorithms . . . . . . . . . . . . . . . . . . 198
9.2 Finding concurrency . . . . . . . . . . . . . . . . . . . . . . . 199
9.3 Strategies for exploiting concurrency . . . . . . . . . . . . . . 200
9.4 Algorithm patterns . . . . . . . . . . . . . . . . . . . . . . . 201
9.5 Patterns supporting parallel source code . . . . . . . . . . . 203
9.6 Demonstrating parallel algorithm patterns . . . . . . . . . . 204