Atomic operations on host mapped memory

Accelerated Computing CUDA CUDA Programming and Performance
1

Is it possible to perform atomic operations on host memory that has been mapped in the device memory using cuMemHostAlloc and cuMemHostGetDevicePointer?

2

Yes, but they are only atomic with regards to the device that is performing the atomic operations.

3

Then, using atomic operations in a host thread to create a shared semaphore would not work, right?

4

Correct–even if you could, I’m not sure how it would perform well enough to be worthwhile.

5

deleted

6

Intel CPUs support cache snooping… So, your CPU thread could do continuous polling to figure out if GPU change a mem location…

No idea about semaphores.

7

I am not concerned about the performance of the implementation, but about the implementability of the mechanism. Just to be sure, would it work?

8

Thanks for the tip. But the problem I’m facing is how to atomically update a single physical memory location from two different devices (CPU/GPU).