~/talk

How Modern PyTorch Supercharges Multimodal Training and Inference at Luma AI

Talkat PyTorch Conference 2025 · 2025-10-22..10-23· [machine-learning]
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slides:none on file

Luma AI ships Ray 3 and Dream Machine (built in five months) and runs multimodal training using a unified forge config system that applies FSDP2/FSTP2 sharding, device meshes, and activation checkpointing set to 100%. Compilation uses torch.compile with regional caches stored in Redis, and inference reuses trained pieces via a lightweight model manager. Async tensor parallelism yields 10–20% runtime gains and a custom KDUNN op on H100s gives about 2–5% improvement over FlashAttention3.

AI-written summary · about

  1. 0:00Introduction to Luma AI
  2. 0:43Understanding multimodality
  3. 1:43Scaling and efficiency
  4. 3:05Experimentation with PyTorch
  5. 5:20Forge configuration system
  6. 11:13Efficient distributed training
  7. 17:35Distributed inference
  8. 18:59Q&A and concluding remarks
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