Concurrency - Help with understanding Profiling Results

Question

I've just converted some of my code to C++ AMP and my application now finishes a lot slower than before (52 ms per frame compared to 20 ms per frame before).

I have tried to use the VS2012 Profiler to analyze what is happening, however I am not making much sense of it. The task scheduler seems to have a huge overhead here.

Anyone with any insight?

My initial guess is that this is due to the C++ AMP memory transfers between host <-> device (copy_async(/*...*/).then(/*...*/)) and what I am seeing is simply the task scheduler waiting/spinning for new work?

Answer 1

Yes, your guess about the task scheduler is correct. There is not enough work in the scheduler. That is why the profile shows time being spent searching for work.

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--Krishnan (Microsoft)