OpenACC for Programmers: Concepts and Strategies

Table of Contents

Chapter 1: OpenACC in a Nutshell 1

1.1 OpenACC Syntax 3

1.2 Compute Constructs 6

1.3 The Data Environment 11

1.4 Summary 15

1.5 Exercises 15

Chapter 2: Loop-Level Parallelism 17

2.1 Kernels Versus Parallel Loops 18

2.2 Three Levels of Parallelism 21

2.3 Other Loop Constructs 24

2.4 Summary 30

2.5 Exercises 31

Chapter 3: Programming Tools for OpenACC 33

3.1 Common Characteristics of Architectures 34

3.2 Compiling OpenACC Code 35

3.3 Performance Analysis of OpenACC Applications 36

3.4 Identifying Bugs in OpenACC Programs 51

3.5 Summary 53

3.6 Exercises 54

Chapter 4: Using OpenACC for Your First Program 59

4.1 Case Study 59

4.2 Creating a Naive Parallel Version 68

4.3 Performance of OpenACC Programs 71

4.4 An Optimized Parallel Version 73

4.5 Summary 78

4.6 Exercises 79

Chapter 5: Compiling OpenACC 81

5.1 The Challenges of Parallelism 82

5.2 Restructuring Compilers 88

5.3 Compiling OpenACC 92

5.4 Summary 97

5.5 Exercises 97

Chapter 6: Best Programming Practices 101

6.1 General Guidelines 102

6.2 Maximize On-Device Compute 105

6.3 Optimize Data Locality 108

6.4 A Representative Example 112

6.5 Summary 118

6.6 Exercises 119

Chapter 7: OpenACC and Performance Portability 121

7.1 Challenges 121

7.2 Target Architectures 123

7.3 OpenACC for Performance Portability 124

7.4 Code Refactoring for Performance Portability126

7.5 Summary 132

7.6 Exercises133

Chapter 8: Additional Approaches to Parallel Programming 135

8.1 Programming Models135

8.2 Programming Model Components142

8.3 A Case Study 155

8.4 Summary170

8.5 Exercises170

Chapter 9: OpenACC and Interoperability 173

9.1 Calling Native Device Code from OpenACC 174

9.2 Calling OpenACC from Native Device Code 181

9.3 Advanced Interoperability Topics 182

9.4 Summary185

9.5 Exercises185

Chapter 10: Advanced OpenACC 187

10.1 Asynchronous Operations 187

10.2 Multidevice Programming 204

10.3 Summary 213

10.4 Exercises 213

Chapter 11: Innovative Research Ideas Using OpenACC, Part I 215

11.1 Sunway OpenACC 215

11.2 Compiler Transformation of Nested Loops for Accelerators 224

Chapter 12: Innovative Research Ideas Using OpenACC, Part II 237

12.1 A Framework for Directive-Based High-Performance Reconfigurable Computing 237

12.2 Programming Accelerated Clusters Using XcalableACC 253

Index 269