OpenCL™ Developer Guide for Intel® Core™ and Intel® Xeon® Processors

  • 10/30/2018
  • Public Content
Contents

Introduction for OpenCL™ Coding on Intel® Architecture Processors

Each work group is assigned to one thread that loops over all work items within the work group with SIMD. So you have parallelism at the work-group level (vector instructions) and parallelism between work-groups (threading).
Generally, you think in terms of “total work” first, which is “global work size” in OpenCL™ notion. Recall that
global-size = work-group-size*number-of-work-groups
. Thus, understanding the trade-offs between work-group size and number of work-groups is very important for both types of parallelism that we just discussed. In this section certain general recommendations are provided.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804