Hi jjzanin,
Thanks! We have done some work on improving the copy performance. We have seen great improvement. It was not included in Beta, but it will be avaliable in final product. Meanwhile, you can use C++ AMP staging array, which should deliver better copy
performance, please see http://blogs.msdn.com/b/nativeconcurrency/archive/2011/11/10/staging-arrays-in-c-amp.aspx.
For the mesurement, another thing to pay attention is the OS page-fault/zeroing-out cost. With C++ AMP, we pay it lazily at first touch. Other may pay it eargly at creation time. So it would be better to warm-up the data before measuring the copy performance
to exclude the zeroing-out cost.
std::vector<int> vec(size);
array<int> arr(size);
// use it for a copy or parallel_for_each, so it's touched
// measure the copy perf
start_timer();
copy(vec.begin(), vec.end(), arr);
stop_timer();
In this way, you focus on the copy perf without the zero-ing out cost. The same strategy probably should be used for OpenCL measurement. Between start_timer and stop_timer, you can also consider repeating the copy function mutliple times,
then get an average.
This blog post give more detail on the C++ AMP time measurement:
http://blogs.msdn.com/b/nativeconcurrency/archive/2011/12/28/how-to-measure-the-performance-of-c-amp-algorithms.aspx. You can user accelerator_view::wait() method to eliminate any asynchony happening in the implementation.
Thanks,
Weirong
