[https://nvbugs/6428124][fix] Include use_host_stop_criteria in the PP send/recv payload in… by trtllm-agent · Pull Request #16134 · NVIDIA/TensorRT-LLM

trtllm-agent · 2026-07-08T19:15:06Z

Summary

Root cause: On non-last PP ranks, sample_state.use_host_stop_criteria stayed False while the last rank's fast host-stop path produced host.finish_reasons=None, so update_requests entered process_draft_tokens with an empty finish_reasons list and raised IndexError.
Fix: Include use_host_stop_criteria in the PP send/recv payload in _ring_broadcast_sample_state and restore it on the receiver, using hasattr/getattr to stay compatible with non-Torch sampler flavors; remove the corresponding waives.txt entry.
Automated fix generated by repair-bot

Test plan

Verify fix on the same GPU type as the original failure
Check for regressions in related tests

Links

Bug: https://nvbugs/6428124

Summary by CodeRabbit

Bug Fixes
- Propagated use_host_stop_criteria in the pipeline-parallel sample-state broadcast.
- Preserved sampler compatibility with hasattr and getattr.
- Prevented inconsistent stop-criteria state across pipeline stages.
Chores
- Removed the outdated Nemotron-H LoRA pipeline-parallel waiver.

Dev Engineer Review

The broadcast fix restores use_host_stop_criteria on receiving ranks.
Sending ranks use False when the sampler does not provide the attribute.
The change addresses the IndexError risk in process_draft_tokens.
The waiver removal uses the existing test path and bug reference format.
No public API declarations changed.

QA Engineer Review

Removed the waiver for TestNemotronHLoRA::test_lora_pp2_sanity.
No test code changed.
No test-db/ or qa/ files changed.
Verdict: needs follow-up because CBTS coverage data is unavailable.

coderabbitai · 2026-07-08T19:18:44Z

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Reviewing files that changed from the base of the PR and between 16260e5 and 76c93cb.

📒 Files selected for processing (2)

tensorrt_llm/_torch/pyexecutor/py_executor.py
tests/integration/test_lists/waives.txt

💤 Files with no reviewable changes (1)

tests/integration/test_lists/waives.txt

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tensorrt_llm/_torch/pyexecutor/py_executor.py

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Walkthrough

The pipeline-parallel ring broadcast now carries use_host_stop_criteria with host state and result diffs. The integration waiver list no longer skips the Nemotron-H LoRA pipeline-parallel sanity test.

Changes

PP Ring Broadcast Flag Propagation

Layer / File(s)	Summary
Ring broadcast flag propagation and validation `tensorrt_llm/_torch/pyexecutor/py_executor.py`, `tests/integration/test_lists/waives.txt`	The receive path applies the received flag when supported. The send path includes the flag and uses `False` when the attribute is unavailable. The waiver for `TestNemotronHLoRA::test_lora_pp2_sanity` is removed.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 76c93

The change synchronizes host-stop criteria across pipeline-parallel ranks and removes the related test waiver; no actionable merge-blocking risk remains beyond normal checks and review.

Possibly related PRs

NVIDIA/TensorRT-LLM#15585: Both pull requests modify the integration test waiver list, but they address different tests and issues.

Suggested reviewers: byshiue, mlefeb01, mzweilz

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the NVBugs fix and the primary change: adding use_host_stop_criteria to the PP send/recv payload.
Description check	✅ Passed	The description explains the root cause, fix, compatibility approach, waiver removal, and test intent. It is mostly complete, although it does not use the template's exact Description and Test Coverag…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Description check

Explanation

The description explains the root cause, fix, compatibility approach, waiver removal, and test intent. It is mostly complete, although it does not use the template's exact Description and Test Coverage headings or include the PR checklist confirmation.

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🧪 Generate unit tests (beta)

Create PR with unit tests

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chienchunhung · 2026-07-08T20:04:37Z

A fix was being worked on: #16096

BowenFu

LGTM — adds use_host_stop_criteria to the PP ring send/recv payload symmetrically (send uses getattr(...,False), recv guards with hasattr); only affects multi-PP-rank sample-state broadcast, and PP=1/default bypasses the loop entirely.

brnguyen2

use_host_stop_criteria doesn't exist anywhere in the repo — grep -rn use_host_stop_criteria tensorrt_llm/ returns only the four lines this PR adds. Neither SampleState (sampler.py:185) nor SampleStateTorch (sampler.py:1128) declares it, so the receiver's hasattr is always False and the sender's getattr(..., False) always ships the default. The change is a no-op apart from widening the payload tuple.

The stated root cause also doesn't hold: host.finish_reasons is only None when the request list is empty (sampler.py:4137/4151); there is no fast host-stop path that leaves it None with requests present.

Please drop this and restore the waives.txt entry until there's a reproduction of the actual failure.

brnguyen2 · 2026-08-11T12:11:17Z

+            # criteria path leaves host.finish_reasons=None, so the flag
+            # governing update_requests's branching must ride the ring with
+            # the host state or non-last ranks index into an empty list.
+            if hasattr(sample_state, "use_host_stop_criteria"):


No SampleState subclass defines use_host_stop_criteria, so this hasattr is always False and the assignment never executes — paired with getattr(sample_state, "use_host_stop_criteria", False) on the send side, the flag round-trips as a constant False. If a flag really is needed here it has to be a declared field on the sample-state dataclass, set by the sampler; a hasattr guard just hides that it isn't.

coderabbitai · 2026-08-15T22:25:46Z

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coderabbitai · 2026-08-18T21:19:41Z

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coderabbitai · 2026-08-22T09:35:17Z

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coderabbitai · 2026-08-26T13:56:46Z

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Nemotron-H LoRA PP=2 crashed with IndexError in finish_if_reason because the last PP rank produced a SampleStateTorch with use_host_stop_criteria=True (and host.finish_reasons=None), but only sample_state.host was sent through _ring_broadcast_sample_state. Non-last ranks kept the constructor default False and tried to index into an empty finish_reasons list from process_draft_tokens. Include the flag in the PP send/recv payload and restore it on the receiver. Use getattr/hasattr to stay compatible with the TRT-LLM sampler flavor which lacks this field. Remove the corresponding waiver. Signed-off-by: trtllm-agent <296075020+trtllm-agent@users.noreply.github.com>

Signed-off-by: handongl <handongl@nvidia.com>

trtllm-agent requested a review from a team as a code owner July 8, 2026 19:15

trtllm-agent requested a review from byshiue July 8, 2026 19:15

trtllm-agent assigned chienchunhung Jul 8, 2026

github-actions Bot assigned trtllm-agent Jul 8, 2026

chienchunhung mentioned this pull request Jul 8, 2026

[https://nvbugs/6428057][fix] Propagate host stop criteria across PP ranks #16131

Closed

trtllm-agent force-pushed the repair-bot-bug6428124 branch from 26e810c to 8d406d5 Compare July 18, 2026 08:39

trtllm-agent requested review from a team as code owners July 18, 2026 08:39

trtllm-agent requested review from BowenFu, YihuiLu512, brnguyen2, crazydemo, mlefeb01, mzweilz, nv-xtf, reasonsolo, yingguo-trt and zhaoyangwang-nvidia July 18, 2026 08:39

yingguo-trt approved these changes Jul 20, 2026

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trtllm-agent force-pushed the repair-bot-bug6428124 branch from 8d406d5 to 72fdc5d Compare July 20, 2026 04:44

BowenFu approved these changes Jul 20, 2026

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crazydemo approved these changes Jul 20, 2026

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trtllm-agent force-pushed the repair-bot-bug6428124 branch from 72fdc5d to d8f8ccf Compare July 22, 2026 22:10

zhaoyangwang-nvidia approved these changes Jul 23, 2026

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trtllm-agent force-pushed the repair-bot-bug6428124 branch from d8f8ccf to 812d4e0 Compare July 24, 2026 07:29

brnguyen2 requested changes Aug 11, 2026

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trtllm-agent force-pushed the repair-bot-bug6428124 branch from 812d4e0 to 1bc4608 Compare August 15, 2026 22:25

This was referenced Aug 15, 2026

[https://nvbugs/6428092][fix] Forward use_host_stop_criteria alongside host and py_result_diffs in the PP… #16133

Open

[https://nvbugs/6618106][fix] Carry single_step_greedy on SampleStateTensorsHostTorch #17828

Merged

trtllm-agent force-pushed the repair-bot-bug6428124 branch from 1bc4608 to f9189f4 Compare August 18, 2026 21:19

trtllm-agent force-pushed the repair-bot-bug6428124 branch from f9189f4 to f30412c Compare August 22, 2026 09:35

trtllm-agent force-pushed the repair-bot-bug6428124 branch from f30412c to 76c93cb Compare August 26, 2026 13:56

trtllm-agent force-pushed the repair-bot-bug6428124 branch from 76c93cb to 4727810 Compare August 28, 2026 06:39

trtllm-agent and others added 2 commits August 30, 2026 09:24

[nvbugs/6428124][chore] Remove stale waiver after fix

dfdc2f4

Signed-off-by: handongl <handongl@nvidia.com>

trtllm-agent force-pushed the repair-bot-bug6428124 branch from 4727810 to dfdc2f4 Compare August 30, 2026 16:26

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[https://nvbugs/6428124][fix] Include use_host_stop_criteria in the PP send/recv payload in… - #16134

[https://nvbugs/6428124][fix] Include use_host_stop_criteria in the PP send/recv payload in…#16134
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