System info: Ubuntu 18.04, g++ 7.4.0, Optix 6.6.0, driver 440.44, cuda 10.0, 2xRTX 2080 Ti
I use thrust to process the results after a launch. I basically store the hits on a
RT_BUFFER_INPUT_OUTPUT with RT_BUFFER_GPU_LOCAL with a custom struct.
After the launch, I would like to manipulate the contents of the buffer with thrust, like, for instance
HitInfo* raw_ptr =static_cast<HitInfo*>( hitBuffer->getDevicePointer(0)); thrust::device_ptr<HitInfo> dev_ptr=thrust::device_pointer_cast(raw_ptr); thrust::partition(dev_ptr, dev_ptr+bsize, hit_on_curved());
Now, code like the one above only works if I force to use only one GPU. If I use multiple GPUs thrust raises a thrust::system::system_error
what(): partition failed to synchronize: an illegal memory access was encountered.
On the contrary, if I copy the results from the optix buffers to another thrust::device_vector with cudaMemcpy, all the thrust algorithms run without problems on it.
So, the questions are, why is it happening? is it possible to use thrust on a optix buffer in general in a multi-GPU environment?
I guess that the answer is possibly in sect. 9.2.3 Zero-copy pointers of the documentation, but I do not get it. As far as I understand, since I use RT_BUFFER_GPU_LOCAL, it does not apply, does it?
Thanks a lot,