• 2019 Update 4
  • 03/20/2019
  • Public Content

Perform Initialization in a Separate Task

Consider the following code snippet:
__kernel void something(const __global int* data) { int tid = get_global_id(0); if (0 == tid) { //Do some one-shot work } barrier(CLK_GLOBAL_MEM_FENCE); //Regular kernel code }
In this example, all work-items encounter the first branch, while the branch is relevant to only one of them. A better solution is to move the initialization phase outside the kernel code, either to a separate kernel, or to the host code.
If you need to run some kernel only once (for a single work-item), use
, which is specially crafted for this purpose.

Product and Performance Information


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