Atomic operations between multiple devices

Question

I am developing something in heterogeneous systems with CPU and GPU (AMD APU, in fact) with OpenCL. Since I will use atomic operations to guarantee the integrity of data, and the data is shared among CPU device and GPU device, on each of which there is a kernel running on the shared data. My question is: is atomic operation still valid between these two devices? Hope anyone can help me. Many thanks.

Answer 1

Appendix A of the OpenCL Specification covers the synchronization of memory objects between different devices. There is no guarantee both devices will access the memory objects at the same physical location: one of the devices may work on a copy of the buffer, and only synchronization as described in Appendix A will ensure the other devices gets a copy of it.

Your implementation on the AMD APU may allow both CPU and GPU to share the same address space, and may not require the inter device synchronization. I would suggest to check AMD documentations and experiment.