Execution Model

OpenCL is a host CPU based library containing APIs that allow you to:

1. Discover available compute devices in the system,
2. Define programs to run on those compute devices,
3. Define buffers that can be used to communicate data between the host program and programs running on compute devices, and
4. To queue work to compute devices.

Step 1 is documented in Device Discovery. Step 3 is documented in Memory Usage. Compilation of programs defined in step 2 is documented in Compilation.

The remaining items:

• The expression of programs in step 2, and
• The mechanisms used to queue work in step 4

are the essence of the execution model as it relates to how work is accomplished on compute devices and is the main topic for this chapter.

• Terminology
• Device Discovery
• Understanding Kernels, Work-groups and Work-items
  • Enqueueing a Kernel
  • Mapping the OpenCL C work-item Built-in Functions
  • OpenCL C Kernel Code
  • NDRangeKernel Execution on DSP Devices