~/lightning

Accelerating PyTorch FSDP Via Overlapping Collectives With In...

Lightningat PyTorch Conference 2025 · 2025-10-22..10-23· [distributed-systems, networking]
links:none on file
slides:none on file

Extension of the UCC library and a prototype chain of Nvidia SHArP plus a zerocopy SPIN backend enables overlapping ReduceScatter and Allgather for PyTorch FSDP using in‑network computing and InfiniBand multicast. Implementation runs on 10‑GPU setups (ConnectX NICs, IB quantum switch) and shows microbenchmarked collective latency down ~22.5% and real LLM training throughput up ~10.7% while claiming up to 2x communication reduction in ideal large‑GPU limits. Overlap requires a custom NCCL/UCC/NPI integration and works without user code changes.

AI-written summary · about

  1. 0:00PyTorch FSDP intro
  2. 1:26FSDP backward bottlenecks
  3. 2:56Reducing backward time
  4. 4:43In-network computing role
  5. 6:31PyTorch prototype
  6. 8:43Performance results
  7. 10:09Takeaways and future
  8. 10:56Q&A
~/search
type to search 6,249 conferences, 138,987 speakers and 185,172 talks
~/help
cmdctrl k
search every conference, speaker and series
/
focus the filter search
h
home
c
conferences
s
speakers
e
series
t
light / dark — the status bar button does the same
?
this help
esc
close this, then clear every filter — or just the search, while you are typing in it

Ignored while you are typing. Pages without a filter rail have no search to focus.