What problem does it solve? Pretraining large language models from scratch requires coordinating complex distributed training strategies across hundreds of GPUs, and configuring FSDP, tensor parallelism, pipeline parallelism, and Float8 quantization correctly is error-prone and time-consuming. ## Core Features & Use Cases - 4D Parallelism Configuration: Compose FSDP2, tensor parallelism, pipeline parallelism, and context parallelism for models from 8B to 405B+ parameters across 8 to 512+ GPUs. - Float8 and torch.compile Optimization: Enable Float8 training with tensorwise or rowwise scaling on H100 GPUs for up to 48% throughput gains. - Checkpoint Management: Use distributed checkpointing with async saves, HuggingFace conversion, seed checkpoints for pipeline parallelism, and resharding across parallelism configurations. - Use Case: Pretrain Llama 3.1 70B on 256 GPUs by generating a TOML config with FSDP plus tensor parallelism, launching via SLURM, and monitoring training through TensorBoard. ## Quick Start Ask the assistant to configure and launch a TorchTitan pretraining run for Llama 3.1 8B on 8 GPUs with a TOML config and checkpointing enabled.