One Slow DDP Rank Can Hold Back Your Whole PyTorch Job
This article discusses a common performance bottleneck in PyTorch Distributed Data Parallel (DDP) jobs. It explains that a single slow DDP rank, even if not causing crashes or out-of-memory errors, can significantly increase the overall training time. The issue is subtle because all GPUs appear to be active, yet the training loop progresses at the pace of the slowest component. AI
IMPACT Optimizing PyTorch DDP performance is crucial for efficient large-scale AI model training.