clock() in opencl

Question

I know that there is function clock() in CUDA where you can put in kernel code and query the GPU time. But I wonder if such a thing exists in OpenCL? Is there any way to query the GPU time in OpenCL? (I'm using NVIDIA's tool kit).

Answer 1

There is no OpenCL way to query clock cycles directly. However, OpenCL does have a profiling mechanism that exposes incremental counters on compute devices. By comparing the differences between ordered events, elapsed times can be measured. See clGetEventProfilingInfo.