Improving training time and GPU utilization in geo-distributed language model training

The widespread adoption of language models (LMs) across multiple industries has caused huge surge in demand for GPUs. Training LMs requires tens of thousands of GPUs and housing them in the same datacenter (DCs) is becoming challenging. We focus on training such models across multiple DCs connected via Wide-Area-Network (WAN). We build ATLAS that speeds up such training time using novel temporal bandwidth sharing and many other design choices. While ATLAS improves the training time, it does not eliminate the bubbles (idle GPU cycles). We built BUBBLETEA that runs prefill-as-a-service (part of LM inference) during the bubbles that improves the GPU utilization substantially without any impact of training. Together, ATLAS and BUBBLETEA improve training time by up to 17X and achieve GPU utilization of up to 94%.