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@QiJune QiJune commented Jul 29, 2025

Summary by CodeRabbit

  • Documentation
    • Updated release notes to clarify that the performance regression for full chunked attention support in the LLaMA4 model specifically affects Hopper GPUs. The root cause is identified and a fix is planned for a future release.

@QiJune QiJune requested a review from a team as a code owner July 29, 2025 07:24
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coderabbitai bot commented Jul 29, 2025

Walkthrough

The release notes for TensorRT-LLM v0.21.0 were updated to clarify that a known performance regression for full chunked attention support with the LLaMA4 model only affects Hopper GPUs. The update also notes that the root cause is identified and a fix is planned for a future release.

Changes

Cohort / File(s) Change Summary
Release Notes Update
docs/source/release-notes.md
Clarified that the known performance regression for LLaMA4 chunked attention affects only Hopper GPUs and mentioned that a fix is forthcoming.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Possibly related PRs

Suggested reviewers

  • schetlur-nv
  • zhuolingwang
  • litaotju

Poem

In the meadow of notes, a detail was found,
Hopper’s the culprit, the issue is bound.
LLaMA4’s attention, chunked and precise,
Soon to be fixed—oh, won’t that be nice!
🐇✨ Release notes hop, clarity’s crown!

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@QiJune QiJune requested review from litaotju and schetlur-nv July 29, 2025 07:24
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Actionable comments posted: 0

🧹 Nitpick comments (1)
docs/source/release-notes.md (1)

76-76: Minor grammar & clarity touch-up recommended

The sentence is hard to parse and has a few grammatical nits (missing space before parenthesis, subject–verb agreement, GPU mention). Consider tightening it for readability:

-In 0.21, full chunked attention support has been added to make sure LLaMA4 model can functionally run with > 8K seq length, while there is a known performance regression(only affect LLaMA4 model) on Hopper due to this functional enhancement. The root cause of the regression has been identified already and the fix will be part of the future release.
+In 0.21, full chunked-attention support was added so that the LLaMA4 model can run with sequence lengths > 8 K. However, this functional enhancement introduces a known performance regression on Hopper GPUs that affects only the LLaMA4 model. The root cause has been identified, and a fix is planned for a future release.
📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between eb157ac and 778ef51.

📒 Files selected for processing (1)
  • docs/source/release-notes.md (1 hunks)
🧰 Additional context used
🧠 Learnings (2)
📓 Common learnings
Learnt from: moraxu
PR: NVIDIA/TensorRT-LLM#6303
File: tests/integration/test_lists/qa/examples_test_list.txt:494-494
Timestamp: 2025-07-28T17:06:08.621Z
Learning: In TensorRT-LLM testing, it's common to have both CLI flow tests (test_cli_flow.py) and PyTorch API tests (test_llm_api_pytorch.py) for the same model. These serve different purposes: CLI flow tests validate the traditional command-line workflow, while PyTorch API tests validate the newer LLM API backend. Both are legitimate and should coexist.
Learnt from: amitz-nv
PR: NVIDIA/TensorRT-LLM#5616
File: tensorrt_llm/executor/worker.py:375-384
Timestamp: 2025-07-17T09:01:27.402Z
Learning: In tensorrt_llm/executor/worker.py, the LoRA adapter cache optimization logic that checks `is_adapter_in_cpu_cache()` and conditionally passes None for weights/config has a known race condition issue that cannot be solved with simple error handling or verification checks. This is a known limitation that requires a more comprehensive solution.
Learnt from: yiqingy0
PR: NVIDIA/TensorRT-LLM#5198
File: jenkins/mergeWaiveList.py:0-0
Timestamp: 2025-07-22T08:33:49.109Z
Learning: In the TensorRT-LLM waive list merging system, removed lines are always located at the end of the merge waive lists, which is why the mergeWaiveList.py script uses reverse traversal - it's an optimization for this specific domain constraint.
Learnt from: yechank-nvidia
PR: NVIDIA/TensorRT-LLM#6254
File: tensorrt_llm/_torch/pyexecutor/model_engine.py:1201-1204
Timestamp: 2025-07-22T09:22:14.726Z
Learning: In TensorRT-LLM's multimodal processing pipeline, shared tensor recovery using `from_shared_tensor()` is only needed during the context phase. Generation requests reuse the already-recovered tensor data and only need to call `strip_for_generation()` to remove unnecessary multimodal data while preserving the recovered tensors. This avoids redundant tensor recovery operations during generation.
Learnt from: CR
PR: NVIDIA/TensorRT-LLM#0
File: CODING_GUIDELINES.md:0-0
Timestamp: 2025-07-28T15:39:50.377Z
Learning: Applies to **/*.{cpp,h,hpp,cc,cxx,cu,py} : All TensorRT-LLM Open Source Software code should contain an NVIDIA copyright header that includes the current year. This includes .cpp, .h, .cu, .py, and any other source files which are compiled or interpreted.
docs/source/release-notes.md (3)

Learnt from: moraxu
PR: #6303
File: tests/integration/test_lists/qa/examples_test_list.txt:494-494
Timestamp: 2025-07-28T17:06:08.621Z
Learning: In TensorRT-LLM testing, it's common to have both CLI flow tests (test_cli_flow.py) and PyTorch API tests (test_llm_api_pytorch.py) for the same model. These serve different purposes: CLI flow tests validate the traditional command-line workflow, while PyTorch API tests validate the newer LLM API backend. Both are legitimate and should coexist.

Learnt from: amitz-nv
PR: #5616
File: tensorrt_llm/executor/worker.py:375-384
Timestamp: 2025-07-17T09:01:27.402Z
Learning: In tensorrt_llm/executor/worker.py, the LoRA adapter cache optimization logic that checks is_adapter_in_cpu_cache() and conditionally passes None for weights/config has a known race condition issue that cannot be solved with simple error handling or verification checks. This is a known limitation that requires a more comprehensive solution.

Learnt from: yechank-nvidia
PR: #6254
File: tensorrt_llm/_torch/pyexecutor/model_engine.py:1201-1204
Timestamp: 2025-07-22T09:22:14.726Z
Learning: In TensorRT-LLM's multimodal processing pipeline, shared tensor recovery using from_shared_tensor() is only needed during the context phase. Generation requests reuse the already-recovered tensor data and only need to call strip_for_generation() to remove unnecessary multimodal data while preserving the recovered tensors. This avoids redundant tensor recovery operations during generation.

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)
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@QiJune
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QiJune commented Jul 29, 2025

/bot skip --comment "doc changes"

@QiJune QiJune enabled auto-merge (squash) July 29, 2025 07:52
@QiJune
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QiJune commented Jul 29, 2025

/bot skip --comment "doc changes"

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PR_Github #13328 [ skip ] triggered by Bot

@tensorrt-cicd
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PR_Github #13328 [ skip ] completed with state SUCCESS
Skipping testing for commit 16519eb

@QiJune QiJune merged commit 418892e into NVIDIA:release/0.21 Jul 29, 2025
3 checks passed
dc3671 pushed a commit to dc3671/TensorRT-LLM that referenced this pull request Aug 1, 2025
dc3671 pushed a commit to dc3671/TensorRT-LLM that referenced this pull request Aug 1, 2025
dc3671 pushed a commit to dc3671/TensorRT-LLM that referenced this pull request Aug 4, 2025
dc3671 pushed a commit that referenced this pull request Aug 4, 2025
lancelly pushed a commit to lancelly/TensorRT-LLM that referenced this pull request Aug 6, 2025
Signed-off-by: junq <[email protected]>
Signed-off-by: Lanyu Liao <[email protected]>
jain-ria pushed a commit to jain-ria/TensorRT-LLM that referenced this pull request Aug 7, 2025
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3 participants