NVIDIA NCCL (NVIDIA Collective Communication Library) is the component responsible for managing the distribution of deep learning model training across multiple GPUs. NCCL provides optimized communication primitives (e.g., all-reduce, all-gather) that enable efficient data exchange between GPUs, both within a single node and across multiple nodes. This is critical for distributed training frameworks like Horovod or PyTorch Distributed Data Parallel (DDP), which rely on NCCL to synchronize gradients and parameters, ensuring scalable and fast training.
cuDNN (B) is a GPU-accelerated library for deep neural network primitives (e.g., convolutions), but it does not handle multi-GPU distribution. CUDA (C) is a parallel computing platform and programming model for NVIDIA GPUs, foundational but not specific to distributed training management. TensorFlow (D) is a deep learning framework that can leverage NCCL for distribution, but it is not the core component responsible for GPU communication. NVIDIA's "NCCL Overview" and "AI Infrastructure and Operations" materials confirm NCCL's role in distributed training.