~/talk

The Ultra-Scale Talk: Scaling Training to Thousands of GPUs

Talkat PyTorch Day France 2025 · on Wednesday, 2025-05-07· [machine-learning, distributed-systems]
slides:none on file

Demonstrates a practical 5D recipe—data, tensor, context, pipeline and expert parallelism—and a running stack that uses nanotron plus PyTorch DDP/FSDP patterns to overlap compute and comms. Claims a global-batch sweet spot near 10 million tokens and shows how naive data-parallel at 32,000 GPUs overshoots that limit. Explains FSDP prefetching, tensor-parallel math split, pipeline scheduling from Deepseek to remove bubbles, and cites real memory limits (very large models that won’t fit one GPU) when scaling to thousands of GPUs.

AI-written summary · about

  1. 0:00Ultra-scale training intro
  2. 1:04GPU cluster architecture
  3. 2:28Single-GPU training
  4. 2:49Data parallelism overhead
  5. 4:16Global batch size limits
  6. 5:21FSDP and model size
  7. 7:08Tensor parallelism
  8. 8:33Context parallelism
  9. 9:39Pipeline parallelism
  10. 10:43Mixture-of-experts parallelism
  11. 11:465D parallelism cheat sheet
  12. 12:07Energy efficiency
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