Implementing CUDA Unified Memory in the PyTorch Framework

Popular deep learning frameworks like PyTorch utilize GPUs heavily for training, and suffer from out-of-memory (OOM) problems if memory is not managed properly. In this paper, we propose a modification that utilizes CUDA Unified Memory (UM) to expand GPU memory to the available host memory space so that practicality for the programmer can increase, and OOM memory errors will not result for any workload. We also pinpoint performance issues that result from our modifications to the framework, and outline future plans like reducing redundant memory copies, prefetching, and memory advising techniques to improve upon our design. Our implementation shows that PyTorch UM performance overheads are minimal when the data footprint is below GPU memory capacity.