Paper · arXiv 2307.12169
Optimized Network Architectures for Large Language Model Training with Billions of Parameters
Weiyang Wang, Manya Ghobadi, Kayvon Shakeri, Ying Zhang, Naader Hasani
A new network architecture optimizes GPU communication for Large Language Model training by partitioning GPUs into high-bandwidth domains, reducing network costs.
Abstract
This paper challenges the well-established paradigm for building any-to-any networks for training Large Language Models (LLMs). We show that LLMs exhibit a unique communication pattern where only small groups of GPUs require high-bandwidth any-to-any communication within them, to achieve near-optimal training performance. Across these groups of GPUs, the communication is insignificant, sparse, and homogeneous. We propose a new network architecture that closely resembles the communication requirement of LLMs. Our architecture partitions the cluster into sets of GPUs interconnected with non-blocking any-to-any high-bandwidth interconnects that we call HB domains. Across the HB domains, the network only connects GPUs with communication demands. We call this network a "rail-only" connection, and show that our proposed architecture reduces the network cost by up to 75% compared to the state-of-the-art any-to-any Clos networks without compromising the performance of LLM training.