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Track AutoModel HybridEP OOM and metric regressions in excluded recipes

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
python

Research direction

Start with the PR #4037 config guard and the listed AutoModel MoE recipe configurations, then reproduce each case using pinned code, container, data, and GPU layout with DeepEP and HybridEP. Capture peak memory and failing allocation sites for OOMs, and repeat metric runs while checking validation thresholds and loss or reward trajectories. Done means re-enabling HybridEP only for recipes that pass functional and nightly checks and removing their exceptions.

Written by the indexing model from the issue text.

Description

Memory

Context

PR #4037 temporarily keeps these AutoModel MoE recipes on dispatcher: deepep after HybridEP regressions were reported:

Recipe Reported result after HybridEP switch
sft-nanov3-30BA3B-2n8g-fsdp2 OOM on PR branch; passed on main
vlm_grpo-nemotron-omni-30ba3b-clevr-1n8g-automodel-ep8.v2 OOM on PR branch; passed on main
vlm_grpo-nemotron-omni-30ba3b-mmpr-4n8g-automodel-ep8.v1 OOM on PR branch; passed on main
sft-gpt-oss-20b-1n8g-fsdp8ep8-automodel Metric failure on both PR branch and main; may be flaky
sft-gpt-oss-20b-1n4g-fsdp4ep4-automodel Metric failure only on PR branch; may be flaky

sft-nanov3-30BA3B-2n4g-fsdp2 inherits the 2n8g Nano backend and is also kept on DeepEP. These are reported observations, not independently reproduced root causes; in particular the GPT-OSS 1n8g failure is not yet attributable to HybridEP.

Follow-up

  • Reproduce each case with pinned code, container, data, and GPU layout, comparing DeepEP and HybridEP on otherwise identical configurations.
  • For OOM cases, capture peak allocated/reserved memory and the failing allocation site.
  • For metric failures, repeat runs and compare the relevant validation threshold and loss/reward trajectory to distinguish regression from flakiness.
  • Re-enable HybridEP only for recipes that pass their functional/nightly checks, then remove their exception from the PR #4037 config guard.
Dominant language
Python
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