Possible Bug with clWaitForEvents

Hi,

I'm trying to do performance testing on FPGA, and I'm using some timing in order to calculate the GFlops of a kernel. In order to make sure I'm waiting for the kernel completion, I use clWaitForEvents, on an event which is being created before enqueuing the kernel. Here is the piece of code I use to enqueue the kernel:

 Event evKernel (algorithm->getKernelName ());
 err = clEnqueueNDRangeKernel (queue, kernel, algorithm->getWorkDim(),
 NULL,
 globalWorkSize,
 localMemSize,
 0, NULL, &evKernel.CLEvent());
 CL_CHECK_ERROR (err);
 err = clWaitForEvents (1, &evKernel.CLEvent());
 evKernel.FillTimingInfo ();

evKernel is a wrapper aroud clEvent object, and the filltiminginfo function works as below:

void Event::FillTimingInfo(const int idx)
{
 int sidx, eidx;
 if (idx == ALL_EVENTS) {
 sidx = 0; eidx = count-1;
 } else
 sidx = eidx = idx;
 for (int i=sidx ; i<=eidx ; ++i) {
 cl_int err;
 err = clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_QUEUED,
 sizeof(cl_ulong), &queuedTime, NULL);
 CL_CHECK_ERROR(err);
 err = clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_SUBMIT,
 sizeof(cl_ulong), &submitTime, NULL);
 CL_CHECK_ERROR(err);
 err = clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_START,
 sizeof(cl_ulong), &startTime, NULL);
 CL_CHECK_ERROR(err);
 err = clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_END,
 sizeof(cl_ulong), &endTime, NULL);
 CL_CHECK_ERROR(err);
 }
}

As you can see, I'm using the clgeteventprofilinginfo in order to get the correct numbers.

For a long time, using this method was giving me non-reasonable performance numbers, which was going above the theoretical performance cap of the FPGA (1.5TFlops). So I got suspicious about the way we do timing and decided to do my own timing, by timestamping before clenqueuendrangekernel,and after the clwaitforevents. When I do that and calculate the difference, it's around 1 milliseconds, while the evkernel givesMuch higher value. As a result, I feel like there is something wrong with event management with Altera OpenCL host API. And I think two issues:

1) clWaitForEvents does not really wait for kernel completion.

2) clGetEventProfilingInfo, does not necessarily reflect the correct value.

Any thought on this? Just for your information, I was working on this for a long time and always wondering something wrong with my GFlops computation. but it turns out the problem is with timing.

Thanks,

Saman