Contents
Preface xi
1 What is Concurrent Programming? 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Concurrency as abstract parallelism . . . . . . . . . . . . . . . . 2
1.3 Multitasking . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 The terminology of concurrency . . . . . . . . . . . . . . . . . 4
1.5 Multiple computers . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6 The challenge of concurrent programming . . . . . . . . . . . . 5
2 The Concurrent Programming Abstraction 7
2.1 The role of abstraction . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Concurrent execution as interleaving of atomic statements . . . . 8
2.3 Justification of the abstraction . . . . . . . . . . . . . . . . . . . 13
2.4 Arbitrary interleaving . . . . . . . . . . . . . . . . . . . . . . . 17
2.5 Atomic statements . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.6 Correctness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.7 Fairness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.8 Machine-code instructions . . . . . . . . . . . . . . . . . . . . . 24
2.9 Volatile and non-atomic variables . . . . . . . . . . . . . . . . . 28
2.10 The BACI concurrency simulator . . . . . . . . . . . . . . . . . 29
2.11 Concurrency in Ada . . . . . . . . . . . . . . . . . . . . . . . . 31
2.12 Concurrency in Java . . . . . . . . . . . . . . . . . . . . . . . . 34
2.13 Writing concurrent programs in Promela . . . . . . . . . . . . . 36
2.14 Supplement: the state diagram for the frog puzzle . . . . . . . . 37
3 The Critical Section Problem 45
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.2 The definition of the problem . . . . . . . . . . . . . . . . . . . 45
3.3 First attempt . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.4 Proving correctness with state diagrams . . . . . . . . . . . . . . 49
3.5 Correctness of the first attempt . . . . . . . . . . . . . . . . . . 53
3.6 Second attempt . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.7 Third attempt . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.8 Fourth attempt . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
3.9 Dekker’s algorithm . . . . . . . . . . . . . . . . . . . . . . . . 60
3.10 Complex atomic statements . . . . . . . . . . . . . . . . . . . . 61
4 Verification of Concurrent Programs 67
4.1 Logical specification of correctness properties . . . . . . . . . . 68
4.2 Inductive proofs of invariants . . . . . . . . . . . . . . . . . . . 69
4.3 Basic concepts of temporal logic . . . . . . . . . . . . . . . . . 72
4.4 Advanced concepts of temporal logic . . . . . . . . . . . . . . . 75
4.5 A deductive proof of Dekker’s algorithm . . . . . . . . . . . . . 79
4.6 Model checking . . . . . . . . . . . . . . . . . . . . . . . . . . 83
4.7 Spin and the Promela modeling language . . . . . . . . . . . . . 83
4.8 Correctness specifications in Spin . . . . . . . . . . . . . . . . . 86
4.9 Choosing a verification technique . . . . . . . . . . . . . . . . . 88
5 Advanced Algorithms for the Critical Section Problem 93
5.1 The bakery algorithm . . . . . . . . . . . . . . . . . . . . . . . 93
5.2 The bakery algorithm for N processes . . . . . . . . . . . . . . 95
5.3 Less restrictive models of concurrency . . . . . . . . . . . . . . 96
5.4 Fast algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
5.5 Implementations in Promela . . . . . . . . . . . . . . . . . . . . 104
