问题
Is there a way to get the used local workgroup size, when you set the value of the local workgroup size in the enqueueNDRangeKernel() function to NULL?
回答1:
There is no standard runtime API for doing this in OpenCL. If you really need to know, you could have the kernel retrieve the work-group size with the get_local_size() function and store the value(s) to a buffer.
The vendor profilers (AMD's CodeXL, Intel's VTune, NVIDIA's command-line profiler) should also tell you what they picked.
来源：https://stackoverflow.com/questions/28811839/local-workgroup-size-null-opencl