CUDA-aware MPI or GPUDirect

Hi,

 I have a question about CUDA-aware MPI and GPUDirect. I am writing a paper in which I believe that I am using GPUDirect but a reviewer commented that I am only using CUDA-aware MPI. On the cluster I am using, I have CUDA 8.0.61, PGI 18.1 and MVAPICH2-GDR/2.3b installed, and in the OpenACC code I am using host_data use_device to send/receive buffers directly between GPUs within a node (as I know GPUDirect RDMA is not working in my present situation but I also know that GPUDirect has many levels and it is an umbralla word).

 Could someone provide some thoughts on this? Thanks!

Best,

Hi wiech97,

GPUDirect is a family of technologies (See: GPUDirect | NVIDIA Developer).

While I don’t know the specifics, I would assume MVAPICH2-GDR/2.3b is using GPUDirect RDMA to implement their CUDA Aware MPI, but you’d need to check with them to make sure.

I don’t know what you wrote in your paper or the specific of the reviewer’s comments, but they would be correct if you said you were using GPUDirect directly (unless you are indeed programming specially using either GPUDirect Storage or GPUDirect RDMA CUDA routines).

-Mat

Mat,

 Got it. Thanks very much!