OpenCL programming guide

Using the new OpenCL (Open Computing Language) standard, you can write applications that access all available programming resources: CPUs, GPUs, and other processors such as DSPs and the Cell/B.E. processor. Already implemented by Apple, AMD, Intel, IBM, NVIDIA, and other leaders, OpenCL has outstanding potential for PCs, servers, handheld/embedded devices, high performance computing, and even cloud systems. This is the first comprehensive, authoritative, and practical guide to OpenCL 1.1 specifically for working developers and software architects.

Written by five leading OpenCL authorities, OpenCL Programming Guide covers the entire specification. It reviews key use cases, shows how OpenCL can express a wide range of parallel algorithms, and offers complete reference material on both the API and OpenCL C programming language.

Through complete case studies and downloadable code examples, the authors show how to write complex parallel programs that decompose workloads across many different devices. They also present all the essentials of OpenCL software performance optimization, including probing and adapting to hardware. Coverage includes

• Understanding OpenCL's architecture, concepts, terminology, goals, and rationale
• Programming with OpenCL C and the runtime API
• Using buffers, sub-buffers, images, samplers, and events
• Sharing and synchronizing data with OpenGL and Microsoft's Direct3D
• Simplifying development with the C++ Wrapper API
• Using OpenCL Embedded Profiles to support devices ranging from cellphones to supercomputer nodes
• Case studies dealing with physics simulation image and signal processing, such as image histograms, edge detection filters, Fast Fourier Transforms, and optical flow math libraries, such as matrix multiplication and high-performance sparse matrix multiplication and more

Figures xv

Tables xxi

Listings xxv

Foreword xxix

Preface xxxiii

Acknowledgments xli

About the Authors xliii

Part I: The OpenCL 1.1 Language and API 1

Chapter 1: An Introduction to OpenCL 3

What Is OpenCL, or . . . Why You Need This Book 3

Our Many-Core Future: Heterogeneous Platforms 4

Software in a Many-Core World 7

Conceptual Foundations of OpenCL 11

OpenCL and Graphics 29

The Contents of OpenCL 30

The Embedded Profile 35

Learning OpenCL 36

Chapter 2: HelloWorld: An OpenCL Example 39

Building the Examples 40

HelloWorld Example 45

Checking for Errors in OpenCL 57

Chapter 3: Platforms, Contexts, and Devices 63

OpenCL Platforms 63

OpenCL Devices 68

OpenCL Contexts 83

Chapter 4: Programming with OpenCL C 97

Writing a Data-Parallel Kernel Using OpenCL C 97

Scalar Data Types 99

Vector Data Types 102

Other Data Types 108

Derived Types 109

Implicit Type Conversions 110

Explicit Casts 116

Explicit Conversions 117

Reinterpreting Data as Another Type 121

Vector Operators 123

Qualifiers 133

Keywords 141

Preprocessor Directives and Macros 141

Restrictions 146

Chapter 5: OpenCL C Built-In Functions 149

Work-Item Functions 150

Math Functions 153

Integer Functions 168

Common Functions 172

Geometric Functions 175

Relational Functions 175

Vector Data Load and Store Functions 181

Synchronization Functions 190

Async Copy and Prefetch Functions 191

Atomic Functions 195

Miscellaneous Vector Functions 199

Image Read and Write Functions 201

Chapter 6: Programs and Kernels 217

Program and Kernel Object Overview 217

Program Objects 218

Kernel Objects 237

Chapter 7: Buffers and Sub-Buffers 247

Memory Objects, Buffers, and Sub-Buffers Overview 247

Creating Buffers and Sub-Buffers 249

Querying Buffers and Sub-Buffers 257

Reading, Writing, and Copying Buffers and Sub-Buffers 259

Mapping Buffers and Sub-Buffers 276

Chapter 8: Images and Samplers 281

Image and Sampler Object Overview 281

Creating Image Objects 283

Creating Sampler Objects 292

OpenCL C Functions for Working with Images 295

Transferring Image Objects 299

Chapter 9: Events 309

Commands, Queues, and Events Overview 309

Events and Command-Queues 311

Event Objects 317

Generating Events on the Host 321

Events Impacting Execution on the Host 322

Using Events for Profiling 327

Events Inside Kernels 332

Events from Outside OpenCL 333

Chapter 10: Interoperability with OpenGL 335

OpenCL/OpenGL Sharing Overview 335

Querying for the OpenGL Sharing Extension 336

Initializing an OpenCL Context for OpenGL Interoperability 338

Creating OpenCL Buffers from OpenGL Buffers 339

Creating OpenCL Image Objects from OpenGL Textures 344

Querying Information about OpenGL Objects 347

Synchronization between OpenGL and OpenCL 348

Chapter 11: Interoperability with Direct3D 353

Direct3D/OpenCL Sharing Overview 353

Initializing an OpenCL Context for Direct3D Interoperability 354

Creating OpenCL Memory Objects fro