Hi,
I want to copy data from linear CUDA memory to pinned memory with zero-copy access. Therefore I get a device pointer by calling cudaHostGetDevicePointer() followed by a cudaMemcpy() operation which reports the device pointer to be invalid.
Is such a copy operation forbidden? Am I supposed to call a kernel for the copy-operation?
Thx,
Marcel
you’re doing a cudaMemcpyDeviceToDevice? hmmm, never occurred to me! It should work in principle, but I bet it won’t right now. Might be fixed in the next version…
If cudaMemcpyDeviceToDevice doesn’t work, then I would expect that cudaMemcpyDeviceToHost using the original host pointer would be just as good.
Unless you’re being tricky and writing a framework and passing pointers everywhere… yeah, needs to be looked at. It’s on my whiteboard of things to do.
cudaMemcpyDeviceToHost works for me, thx External Image
I have another question concerning zero-copy access:
If I call a kernel and pass a const device pointer to mapped memory, does the framework recognize that no device-to-host synchronization after the kernel execution is needed (in the dedicated graphics board case)?
