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Getting Help and Support
Introduction
Check-list for OpenCL™ Optimizations
Tips and Tricks for Kernel Development
Application-Level Optimizations
Debugging OpenCL™ Kernels on Linux* OS
Performance Debugging with Intel® SDK for OpenCL™ Applications
Coding for the Intel® Architecture Processors
Why Optimizing Kernels Is Important?
Avoid Spurious Operations in Kernels
Avoid Handling Edge Conditions in Kernels
Use the Preprocessor for Constants
Prefer (32-bit) Signed Integer Data Types
Prefer Row-Wise Data Accesses
Use Built-In Functions
Avoid Extracting Vector Components
Task-Parallel Programming Model Hints
Common Mistakes in OpenCL™ Applications
Introduction for OpenCL™ Coding on Intel® Architecture Processors
Vectorization Basics for Intel® Architecture Processors
Vectorization: SIMD Processing Within a Work Group
Benefitting from Implicit Vectorization
Vectorizer Knobs
Targeting a Different CPU Architecture
Using Vector Data Types
Writing Kernels to Directly Target the Intel® Architecture Processors
Work-Group Size Considerations
Threading: Achieving Work-Group Level Parallelism
Efficient Data Layout
Using the Blocking Technique
Intel® Turbo Boost Technology Support
Global Memory Size
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Mapping Memory Objects (USE_HOST_PTR)
As the host code shares the physical memory with CPU OpenCL™ device, you can do one of the following to avoid unnecessary copies:
- Request the framework to allocate memory on the host.
- Allocate properly aligned memory yourself and share the pointer with the framework.
- Use calls to clEnqueueMapBuffer and clEnqueueUnmapBuffer instead of calls to clEnqueueReadBuffer or clEnqueueWriteBuffer.
If your application uses a specific memory management algorithm, or if you need more control over memory allocation, you can allocate a buffer and then pass the pointer at clCreateBuffer time with the CL_MEM_USE_HOST_PTR flag. However, the pointer must be aligned to the certain boundary. Otherwise, the framework may perform memory copies. Consider to query the required memory alignment using clGetDeviceInfo with CL_DEVICE_MEM_BASE_ADDR_ALIGN token.
You can also map image objects (for CPU OpenCL device), creating them with the CL_MEM_USE_HOST_PTR flag.
See Also
OpenCL™ 1.2 Specification at https://www.khronos.org/registry/OpenCL/specs/opencl-1.2.pdf
Overview Presentations of the OpenCL™ Standard at https://www.khronos.org/registry/OpenCL