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[OMNIML-6032] Deprecate TensorRT-LLM model_type in favor of Hugging Face model_type - #2569

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@shengliangxu shengliangxu commented Sep 28, 2026 •

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What does this PR do?

Type of change: Deprecation / refactor

get_model_type() and MODEL_NAME_TO_TYPE in modelopt.torch.export.model_utils return TensorRT-LLM model names (gpt, llama, qwen, deepseek, …) derived by substring-matching the model class name. The only real consumer is the TensorRT-LLM checkpoint export, which is already deprecated for removal in 0.49.0. examples/hf_ptq used these names for all of its model-specific behavior. This PR switches it to the Hugging Face model_type and deprecates the TRT-LLM names.

  • Library

    • The name table moves to modelopt/torch/export/trtllm/decoder_type.py, next to the TRT-LLM exporter it serves. It goes away with that exporter in 0.49.0.
    • export_tensorrt_llm_checkpoint / torch_to_tensorrt_llm_checkpoint accept decoder_type=None and detect it from the model class. An unrecognized HF model falls back to the generic decoder export with a warning, which is what hf_ptq did before, so no caller has to know TRT-LLM names.
    • get_model_type and MODEL_NAME_TO_TYPE keep working but emit a DeprecationWarning (removal in 0.49.0).
  • examples/hf_ptq keys everything on the root model's config.model_type, via the existing library helper modelopt.torch.models.hf_model_type (already used by export and the model-spec registry).

    • It no longer replaces model_type with the extracted VLM language model's type. A sub-model reports its own sub-config type, and those are not stable. Checking transformers 5.14 configs, 112 of 113 VLMs with a text_config give the language model a different type from the root: qwen3_vl → qwen3_vl_text, mistral3 → mistral, llava → llama. Transformers 4.49 had no separate language model for qwen2_vl. The root type is stable, because it is the config.json key that AutoConfig dispatches on. The --recipe path already used the root type.
    • Encoder-decoder detection (preview decode, and routing to TRT-LLM export) covers t5, mt5, umt5, bart, mbart and whisper. This matches what the old class-name match routed there.
    • The DeepSeek generation skip (out-of-memory risk) matches deepseek* and kimi_k2*. Kimi-K2 (kimi_k2, DeepseekV3ForCausalLM) and Kimi-K2.5 (kimi_k25) are DeepSeek-V3 architectures under their own model_type, and the old class-name match skipped both.
  • Other HF model_type checks in the library now use the root type too. requantize_resmooth_fused_llm_layers (HF export) kept a local model_type that was really the lowercased class name. Its Whisper and Nemotron-VL checks now use the HF model_type. Every Nemotron-VL checkpoint (NemotronH_Nano_VL_V2, Llama_Nemotron_Nano_VL, nemotron_parse) has nemotron in its model_type, matched case-insensitively as before. The Step-family check in the quantization plugin and the Qwen2.5-Omni check in the llama_factory example use hf_model_type instead of inline getattr chains.

  • Fixes and docs

    • The AutoQuantization notebook passed model_type="llama" to export_tensorrt_llm_checkpoint, whose parameter is decoder_type, so its default tensorrt_llm export raised TypeError. It now omits the argument and defaults EXPORT_FMT to hf.
    • The modelopt_recipes/model_type/ README now says to name directories by the top-level model_type, which the existing directories already follow, rather than a multimodal model's text_config.model_type.

Deliberately unchanged:

  • Encoder-decoder checks stay separate. dataset_utils.model_type_is_enc_dec decides how to call the module being calibrated (generate() or a plain forward), and that module can be a sub-model. It matches class names broadly (LongT5, T5Gemma, PLBart), and moving it to a list of HF types would change calibration.
  • Places that already hold a config object read config.model_type directly. hf_model_type also accepts a model, which it detects by looking for a .config attribute; that adds nothing when given a config.

Behavior changes (intentional):

  • Nemotron-H VL (NemotronH_Nano_VL_V2) now runs the Nemotron-VL preview instead of the nemotron_h generation skip. Both generation helpers there catch their own exceptions, so the worst case is a logged failure.
  • T5Gemma, LongT5 and PLBart were routed to the TRT-LLM exporter as t5/bart by substring match. They now use the unified HF export.

Usage

# Before (deprecated, warns):
from modelopt.torch.export import get_model_type
decoder_type = get_model_type(model)  # TensorRT-LLM name, e.g. "qwen"

# After:
model_type = model.config.model_type  # Hugging Face name, e.g. "qwen3_vl"

# The deprecated TRT-LLM exporter no longer needs the TRT-LLM name:
from modelopt.torch.export.trtllm import export_tensorrt_llm_checkpoint
export_tensorrt_llm_checkpoint(model, export_dir=export_dir)

Testing

  • pytest tests/unit/torch/{models,export,speculative,quantization/plugins} tests/unit/torch/puzzletron/test_resolve_descriptor_caching.py tests/unit/recipe/test_step3p7_recipes.py: 771 passed (CPU).
  • pytest tests/examples/hf_ptq tests/unit/recipe, excluding the GPU/model-download suites: 570 passed (CPU).
  • Hub config.json checks (DeepSeek-V3, Kimi-K2/K2.5, Moonlight, Nemotron-H and the Nemotron VL checkpoints), and a comparison of transformers 4.49 with 5.14, for the root vs sub-config model_type findings above.
  • New tests:
    • tests/unit/torch/export/trtllm/test_trtllm_decoder_type.py: decoder-type detection, both deprecation warnings, and the exporter's detection and fallback.
    • tests/examples/hf_ptq/test_hf_ptq_model_type.py: the generation-skip rule, including kimi_k2 and kimi_k25, and the encoder-decoder list.
  • pre-commit (ruff, mypy, bandit, …) clean.
  • Not yet run: GPU end-to-end hf_ptq runs (DeepSeek/Kimi skip, Nemotron-H VL preview, int8_smoothquant TRT-LLM export fallback) and the Whisper / Nemotron-VL export requantization path.

Before your PR is "Ready for review"

  • Is this change backward compatible?: ✅ get_model_type / MODEL_NAME_TO_TYPE still work, with a DeprecationWarning. decoder_type becomes optional.
  • If you copied code from any other sources or added a new PIP dependency, did you follow guidance in CONTRIBUTING.md: N/A
  • Did you write any new necessary tests?: ✅
  • Did you update Changelog?: ✅ (0.48.0 deprecations)
  • Did you get Claude approval on this PR?: ❌ (draft)

Additional Information

Follows the 0.48.0 deprecation of the TensorRT-LLM checkpoint export. Both are removed together in 0.49.0.

Summary by CodeRabbit

  • New Features
    • TensorRT-LLM checkpoint exports can infer the decoder type for supported Hugging Face models when it is omitted.
    • Hugging Face PTQ recognizes additional encoder-decoder model types and skips preview generation for selected model families.
  • Updates
    • Hugging Face is now the default export format in the auto-quantization notebook.
    • Legacy TensorRT-LLM model-type helpers are deprecated and scheduled for removal in version 0.49.0; use the model’s configured Hugging Face model type instead.
    • Multimodal recipe guidance now points to the top-level model type in config.json.

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  • CHANGELOG.rst
  • examples/hf_ptq/example_utils.py
  • examples/hf_ptq/hf_ptq.py
  • examples/llm_qat/llama_factory/llama_factory.py
  • modelopt/torch/export/model_utils.py
  • modelopt/torch/export/trtllm/model_config_export.py
  • modelopt/torch/quantization/plugins/huggingface.py

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📝 Walkthrough

Walkthrough

TensorRT-LLM checkpoint export can detect decoder types from model classes when decoder_type is omitted. The change deprecates prior model-name APIs and updates Hugging Face model-type handling in export, quantization, and examples.

Changes

Model type and export updates

Layer / File(s) Summary
Decoder-type lookup and deprecated aliases
modelopt/torch/export/trtllm/decoder_type.py, modelopt/torch/export/model_utils.py, tests/unit/torch/export/trtllm/test_trtllm_decoder_type.py
An ordered mapping detects decoder types from model class names. get_model_type and MODEL_NAME_TO_TYPE emit deprecation warnings and delegate to or expose the new mapping.
Optional decoder type in checkpoint export
modelopt/torch/export/trtllm/model_config_export.py, tests/unit/torch/export/trtllm/test_trtllm_decoder_type.py, examples/hf_ptq/README.md, examples/hf_ptq/notebooks/3_PTQ_AutoQuantization.ipynb, CHANGELOG.rst
Both checkpoint export APIs accept an omitted decoder type and attempt class-based detection. If detection fails, export uses a generic decoder when architectures are configured, or raises ValueError. The notebook defaults to Hugging Face export.
Hugging Face PTQ model-type handling
examples/hf_ptq/hf_ptq.py, examples/hf_ptq/example_utils.py, tests/examples/hf_ptq/*
The PTQ example uses the root Hugging Face model type and retains it when extracting a language model. Encoder-decoder checks, prompt decoding, and generation skip conditions are updated. Tests cover model-type classifications and generation behavior.
Hugging Face model-type consumers
examples/llm_qat/llama_factory/llama_factory.py, modelopt/torch/export/unified_export_hf.py, modelopt/torch/quantization/plugins/huggingface.py, modelopt_recipes/model_type/README.md, tests/unit/torch/export/test_llm_dummy_forward.py
Qwen2.5-Omni and Step-family checks use hf_model_type. Dummy-forward handling updates Whisper and Nemotron VL detection. Recipe guidance specifies the top-level model type for multimodal models.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Refactor

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant export_tensorrt_llm_checkpoint
  participant get_decoder_type
  Caller->>export_tensorrt_llm_checkpoint: Call with decoder_type omitted
  export_tensorrt_llm_checkpoint->>get_decoder_type: Resolve decoder type from model class
  get_decoder_type-->>export_tensorrt_llm_checkpoint: Return decoder type or None
  export_tensorrt_llm_checkpoint-->>Caller: Export, warn and use unknown class-name type, or raise ValueError
Loading

Merge Risk: 🔵 Low · up to abf6d

Exports that omit decoder_type for unrecognized model classes can still fail despite the documented generic fallback. Passing an explicit type provides a workaround, so this is a bounded risk to the new export behavior.

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 warning)

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Docstring Coverage ⚠️ Warning Docstring coverage is 54.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 50 functions across 12 files. (1 skipped:… Write docstrings for the functions missing them to satisfy the coverage threshold.
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Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check ✅ Passed The title clearly summarizes the primary change: deprecating the TensorRT-LLM model_type APIs in favor of the Hugging Face model_type.
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.
Security Anti-Patterns ✅ Passed No listed security anti-pattern was introduced. The added-line scan for all changed modelopt and examples Python files found no unsafe torch.load, pickle-enabled NumPy load, hardcoded `trust_rem…
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@shengliangxu
shengliangxu force-pushed the shengliangx/deprecating-trtllm-model_type branch from 23983fa to 1c33dea Compare September 28, 2026 20:20
get_model_type and MODEL_NAME_TO_TYPE return TensorRT-LLM model names,
which only the deprecated TensorRT-LLM checkpoint export consumes.

- Move the name table into modelopt.torch.export.trtllm.decoder_type.
- export_tensorrt_llm_checkpoint / torch_to_tensorrt_llm_checkpoint now
  detect decoder_type when omitted, falling back to the generic decoder
  export for unrecognized Hugging Face models as hf_ptq did before.
- get_model_type and MODEL_NAME_TO_TYPE emit a DeprecationWarning and
  will be removed in 0.49.0 together with the TensorRT-LLM export.
- examples/hf_ptq keys model-specific behavior on the root model's
  model_type via modelopt.torch.models.hf_model_type. A VLM's language
  model reports its own sub-config type, which varies across transformers
  versions, so it is no longer used. The DeepSeek generation skip now also
  covers kimi_k2/kimi_k25, DeepSeek-V3 architectures under their own
  model_type.
- The HF export's Whisper and Nemotron VL checks, the Step-family check in
  the quantization plugin and the Qwen2.5-Omni check in the llama_factory
  example use the root HF model_type instead of class names or inline
  getattr chains.
- The AutoQuantization notebook passed model_type="llama" to
  export_tensorrt_llm_checkpoint, whose parameter is decoder_type, so its
  default tensorrt_llm export raised TypeError. Drop the argument and
  default EXPORT_FMT to hf.
- The model_type recipes README says to use the top-level model_type for
  multimodal models, matching the existing directories.

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
@shengliangxu
shengliangxu force-pushed the shengliangx/deprecating-trtllm-model_type branch from 1c33dea to b90a94e Compare September 28, 2026 20:31
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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.90%. Comparing base (f977c05) to head (abf6d48).

Additional details and impacted files
@@            Coverage Diff             @@
##             main    #2569      +/-   ##
==========================================
+ Coverage   69.72%   78.90%   +9.18%     
==========================================
  Files         611      612       +1     
  Lines       68303    68325      +22     
==========================================
+ Hits        47624    53913    +6289     
+ Misses      20679    14412    -6267     
Flag Coverage Δ
examples-diffusers 21.37% <24.00%> (+0.03%) ⬆️
examples-gpt-oss 13.61% <22.00%> (+<0.01%) ⬆️
examples-hf_ptq 23.33% <60.00%> (+0.12%) ⬆️
examples-llm_distill 13.68% <22.00%> (+<0.01%) ⬆️
examples-llm_eval 17.64% <46.00%> (+0.08%) ⬆️
examples-llm_qat 17.79% <46.00%> (+<0.01%) ⬆️
examples-llm_sparsity 16.06% <22.00%> (+<0.01%) ⬆️
examples-megatron_bridge 26.60% <24.00%> (-0.09%) ⬇️
examples-specdec_bench 13.38% <22.00%> (+<0.01%) ⬆️
examples-speculative_decoding 17.99% <46.00%> (-0.03%) ⬇️
examples-torch_onnx 21.93% <24.00%> (+0.03%) ⬆️
examples-torch_trt 15.42% <24.00%> (+0.01%) ⬆️
examples-vllm_serve 13.86% <22.00%> (+<0.01%) ⬆️
gpu 58.48% <46.00%> (+36.91%) ⬆️
regression 15.30% <22.00%> (+<0.01%) ⬆️
unit 59.55% <98.00%> (+0.03%) ⬆️

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@shengliangxu
shengliangxu marked this pull request as ready for review September 28, 2026 23:17
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shengliangxu requested review from a team as code owners September 28, 2026 23:17

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  • 🪄 Fix CodeRabbit comments on this PR
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Inline comments:
Review comments at @CHANGELOG.rst:
- Line 75: Update the changelog entry for `get_model_type` and
`MODEL_NAME_TO_TYPE` to use no more than two sentences: combine the deprecation
and migration guidance in the first, then summarize
`export_tensorrt_llm_checkpoint` decoder inference and the `examples/hf_ptq`
change in the second.

Review comments at @modelopt/torch/export/trtllm/model_config_export.py:
- Line 173: Update the architecture resolution before the
MODEL_NAME_TO_HF_ARCH_MAP lookup so a missing config.architectures does not
produce an unknown:<model class> key that raises KeyError. In the decoder_type
fallback, resolve an architecture accepted by TensorRT-LLM’s MODEL_MAP or use an
explicit generic fallback before the lookup.

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📒 Files selected for processing (15)
  • CHANGELOG.rst
  • examples/hf_ptq/README.md
  • examples/hf_ptq/example_utils.py
  • examples/hf_ptq/hf_ptq.py
  • examples/hf_ptq/notebooks/3_PTQ_AutoQuantization.ipynb
  • examples/llm_qat/llama_factory/llama_factory.py
  • modelopt/torch/export/model_utils.py
  • modelopt/torch/export/trtllm/decoder_type.py
  • modelopt/torch/export/trtllm/model_config_export.py
  • modelopt/torch/export/unified_export_hf.py
  • modelopt/torch/quantization/plugins/huggingface.py
  • modelopt_recipes/model_type/README.md
  • tests/examples/hf_ptq/test_hf_ptq_model_type.py
  • tests/examples/hf_ptq/test_hf_ptq_vision_quantization.py
  • tests/unit/torch/export/trtllm/test_trtllm_decoder_type.py

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Comment thread modelopt/torch/export/trtllm/model_config_export.py
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Claude review — 2 IMPORTANT, 2 SUGGESTION, 0 CRITICAL

Scope: full review (trigger comment carried no scoping instructions). All 15 changed files considered; modelopt/ (5 files) and examples/ (5 files) read with surrounding context, tests/ (3 files) read from the diff, CHANGELOG.rst / modelopt_recipes/model_type/README.md skimmed.

Assessment

The core premise is right and unusually well-researched: keying examples/hf_ptq on the root config.model_type rather than a sub-model's, with the transformers 4.49-vs-5.14 survey in the PR body to back it, is the correct call. I traced every model_type consumer in hf_ptq.py (lines 267, 688, 909, 953, 1074, 1082, 1086, 1163, 1206, 1337, 1461) against the old TRT-LLM name it used to receive, and the old→new mapping is behavior-preserving in each case, including the non-obvious ones: MT5ForConditionalGeneration previously resolved to the TRT-LLM name "t5" and so already took the enc-dec path, which is exactly why adding mt5/umt5/mbart to is_enc_dec is a no-op rather than a widening. llama4_text is a real root type (Llama4ForCausalLM uses Llama4TextConfig), not defensive padding. The MODEL_NAME_TO_TYPE alias returns the same dict object, so the one plausible downstream use — mutating the table to register a custom model — keeps working, and the module-level __getattr__ keeps the DeprecationWarning off the package-import path since the name was never in __all__.

Two issues are worth fixing before merge; neither is in the refactor's main line.

IMPORTANT

1. unified_export_hf.py:512 — Nemotron-VL detection now keys on config.model_type, against the repo's own convention. The two other Nemotron detectors (model_utils.py:116, example_utils.py:252) both key on config.architectures, as does the is_multimodal_model gate immediately above this line. For remote-code VLMs architectures is the field the loader dispatches on and is always present; model_type is free-form. If one config's model_type lacks nemotron (or is absent — hf_model_type returns None), the branch is skipped and the fallback dummy-forwards the full VLM, which is the pixel_values crash the branch exists to prevent. The PR body's hub survey covers today's checkpoints; the concern is the weaker invariant going forward. Switching to architectures is a two-line change and makes the three call sites agree.

2. model_config_export.py:167-173 — the new "Required for Megatron-Core models" docstring is unenforced, and detection cannot satisfy it. get_decoder_type(GPTModel) returns None (no table key is a substring of gptmodel), so the value becomes unknown:GPTModel; architecture stays "" because it is only filled from model.config.architectures, which Megatron models lack; MODEL_NAME_TO_HF_ARCH_MAP[decoder_type] then raises KeyError, which the try at line 545 swallows into a generic "Cannot export" warning that never names the missing argument. A caller who previously got a clear TypeError at the call site now pays a full weight-conversion pass for an opaque failure. Relatedly, when architecture does resolve, the checkpoint is written with "decoder": "unknown:<Class>" (tensorrt_llm_utils.py:175), which TRT-LLM cannot consume — so "Continue exporting..." yields an unloadable checkpoint rather than a working generic export. Raising when detection fails and the model has no config.architectures preserves the documented contract and confines the fallback to cases where it actually works. This overlaps CodeRabbit's line-173 comment; the Megatron enforcement angle and the invalid "decoder" field are the parts it did not cover.

SUGGESTION

  1. hf_ptq.py:909 — refusal message still reads "(t5/bart/whisper)" after is_enc_dec grew to six types.
  2. example_utils.py:903 — the T5 NaN and BART meta-tensor load workarounds at lines 707/711 still exact-match "t5"/"bart", so MT5/MBart are recognized as enc-dec but not covered by the architecture-level workarounds they share. Pre-existing, optional here.

Not flagged, checked and clear

mono_quantize's unused model_type parameter (pre-existing, outside the diff); the post_quantize assert preview_input_ids is not None (holds — pre_quantize only returns None on the specdec_offline_dataset path, which early-exits above); the lazy .trtllm.decoder_type import in model_utils (deferred into the function body, so no cycle with modelopt.torch.export); assert model_type != "dbrx" (HF type is also dbrx); the whisper change at line 501 (WhisperConfig.model_type is a transformers constant); and the deliberately-unchanged dataset_utils.model_type_is_enc_dec, whose divergence the existing comment already explains.

Risk

Moderate. The deprecation shims and the examples/hf_ptq refactor are low-risk and well-tested. Risk concentrates in the two items above, both on paths the PR's own Testing section lists as not yet exercised on GPU (Nemotron-VL export requantization, int8_smoothquant TRT-LLM export fallback).

Comment thread modelopt/torch/export/unified_export_hf.py Outdated
Comment thread modelopt/torch/export/trtllm/model_config_export.py
Comment thread examples/hf_ptq/hf_ptq.py Outdated
Comment thread examples/hf_ptq/example_utils.py
…cating-trtllm-model_type

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>

# Conflicts:
#	examples/hf_ptq/hf_ptq.py
- export_tensorrt_llm_checkpoint: when decoder_type cannot be detected,
  raise a clear ValueError unless the model has config.architectures for
  the generic decoder path. A Megatron-Core caller that omits decoder_type
  otherwise failed late with KeyError: 'unknown:GPTModel'.
- requantize_resmooth_fused_llm_layers: detect Nemotron VL from
  config.architectures, like is_multimodal_model and is_nemotron_vl, since
  model_type is free-form for these remote-code models.
- Drop the stale "(t5/bart/whisper)" from the layerwise-export refusal
  label; is_enc_dec also covers mt5, umt5 and mbart.
- Shorten the CHANGELOG entry to two sentences.

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
@shengliangxu
shengliangxu added this pull request to stack #2631 October 1, 2026 22:32

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Bot review (gpt-6.1-sol) — DM the bot to share feedback.

Changes requested: encoder-decoder previews now truncate generated answers, and Nemotron-VL export detection loses its class-name fallback.

Needs action:

  • Separate preview decoding from export routing in examples/hf_ptq; preserve encoder-decoder decoding for LongT5, T5Gemma and PLBart while keeping their intended HF export.
  • Preserve Nemotron-VL requantization when config.architectures is unset in unified_export_hf.py, and add a regression exercising the language-model-only forward.
  • Add focused Whisper dummy-forward and root-versus-extracted-VLM model-type regressions; current tests do not exercise those changed export/selection paths.
  • Move the new local imports in model_utils.py to module scope, or document a concrete circular-import reason.

No action needed:

  • The design reuses hf_model_type; the PR body justifies retaining legacy TRT-LLM detection instead of extending the HF registry.
  • Existing vision-test edits follow the changed extraction contract without weakening assertions. New headers match LICENSE_HEADER.

Comment thread examples/hf_ptq/example_utils.py
Comment thread modelopt/torch/export/unified_export_hf.py Outdated
Comment thread modelopt/torch/export/model_utils.py
- hf_ptq: separate the preview decode from TensorRT-LLM export routing.
  is_trtllm_enc_dec_export(model_type) keeps the exporter's families (t5,
  mt5, umt5, bart, mbart, whisper); generate_excludes_prompt(model) uses the
  root config's is_encoder_decoder, minus DiffusionGemma. LongT5 and PLBart
  matched the legacy t5/bart names and decoded whole; keying both on the
  export list sliced a prompt-length prefix off their answers. T5Gemma,
  which the legacy table matched as gemma, now decodes whole too.
- unified_export_hf: lift the requantization dummy forward into
  _llm_dummy_forward, and detect Nemotron VL from config.architectures or the
  class name, so a model built from a config without architectures keeps
  the language-model-only forward.
- model_utils: document why the deprecation shims import .trtllm lazily
  (trtllm -> model_config_export -> quant_utils -> model_utils cycle).
- Tests: preview decode with an answer shorter than the prompt, Whisper and
  Nemotron VL dummy forwards (architectures set and unset), and load_model
  keeping the root model_type when it extracts a VLM's language model.

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
@shengliangxu

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@cjluo-nv thanks for the review. All four action items are addressed in a5dd506:

  • Preview decode vs export routing: split into generate_excludes_prompt and is_trtllm_enc_dec_export; see the inline thread.
  • Nemotron VL without config.architectures: falls back to the class name; see the inline thread.
  • Regression tests:
    • tests/unit/torch/export/test_llm_dummy_forward.py covers the Whisper dummy forward (mel-spectrogram input of shape [1, num_mel_bins, nb_max_frames] plus decoder_input_ids) and the Nemotron VL language-model-only forward.
    • test_image_calibration_model_target_follows_recipe now asserts that load_model returns the root model_type (qwen3_vl) when it extracts the language model, which reports qwen3_vl_text.
  • Local imports in model_utils.py: kept deferred because of a real import cycle, now documented; see the inline thread.

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Bot review (gpt-6.1-sol) — DM the bot to share feedback.

LGTM: prior correctness concerns are resolved; human sign-off remains for the justified existing vision-test update.

Needs action:

  • Confirm the justified update to test_hf_ptq_vision_quantization.py: it follows the extraction return contract and adds root-model-type coverage without weakening existing assertions.

No action needed:

  • ✔️ Resolved the preview truncation, Nemotron-VL class-name fallback, missing Whisper/VLM regressions, early decoder-type validation, and documented circular imports.
  • The design reuses hf_model_type rather than adding another registry; retaining legacy detection beside the deprecated exporter is justified.
  • New file headers match LICENSE_HEADER. The pre-existing T5/BART loading workarounds can remain a separate follow-up.
  • Tests were inspected, not executed in this review.

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Confirmed: the test_hf_ptq_vision_quantization.py change follows the new extract_and_prepare_language_model_from_vl return contract (it returns only the language model). The hf_model_type mock now returns the sub-config type for the extracted language model, and a new assertion checks that load_model keeps the root model_type. No existing assertion was removed or weakened.

@shengliangxu
shengliangxu merged commit e3c903c into main Oct 2, 2026
77 of 81 checks passed
@shengliangxu
shengliangxu deleted the shengliangx/deprecating-trtllm-model_type branch October 2, 2026 01:12
@shengliangxu shengliangxu changed the title Deprecate TensorRT-LLM model_type in favor of Hugging Face model_type [OMNIML-6032] Deprecate TensorRT-LLM model_type in favor of Hugging Face model_type Oct 9, 2026
shengliangxu added a commit that referenced this pull request Oct 9, 2026
…dels [4/4] (#2580)

### What does this PR do?

Type of change: Refactor

### Summary of the series

Model-specific PTQ modeling moves out of
`modelopt/torch/quantization/plugins/huggingface.py` into the per-model
packages under `modelopt/torch/models/<model_type>/modeling_ptq.py`,
next to each model's `specs.py`. By the end of the series
`huggingface.py` shrinks from ~1880 to ~1500 lines and keeps only the
code shared across models: sequential/fused MoE auto-detection,
attention, `FP8Linear`, `CompressedLinear`, parallel linears, and the
transposed-quantization helpers that gpt_oss and llama4 share. Model
types that gain PTQ modeling but had no `ModelSpec` get one.

- Class and function bodies move verbatim. The only rewrites: on-the-fly
callbacks are added to `CUSTOM_MODEL_PLUGINS` by their own module, and
`is_homogeneous_hf_model` imports `is_nemotron_h_model` lazily.
- `huggingface.py` imports every `modeling_ptq` from an explicit list.
The list sits after the generic wrappers these modules build on and
before the homogeneous decoder discoverer is registered, so Nemotron-H's
more specific discoverer still matches first.
- Each package's `__init__.py` keeps importing only `specs`, so `import
modelopt.torch.models` does not pull in quantization or transformers.
- No public API or quantization behavior changes; only private
(`_`-prefixed) names change module.

Merge in order. #2576, #2577 and #2578 have merged; this last slice,
#2580, now targets `main`.

1. #2576 — Add model specs for llama4, qwen3_vl_moe, falcon, step3p5 and
step3p7 (merged)
2. #2577 — Add the `modeling_ptq.py` convention; move Nemotron-H, Falcon
and Llama4 (merged)
3. #2578 — Move GPT-OSS (merged)
4. #2580 — Move the Step family (step3p5, shared by step3p7) ← **this
PR**

The DBRX slice (#2579) was dropped: #2649 removed DBRX support, so there
was nothing left to move. Likewise, the Qwen3-VL-MoE half of [3/4] was
dropped: #2670 removed its pre-5.12 wrapper.

### This PR [4/4]

Moves `_QuantMoELinear`, `_is_expert_indexed_moe_linear`,
`_is_step_family_model`, `register_moe_linear_on_the_fly` and
`_reconstruct_fused_moe_linear` into `step3p5/modeling_ptq.py`, which
also serves `step3p7`. This carries over #2569's switch of
`_is_step_family_model` to `hf_model_type`; `huggingface.py` drops its
now-unused `hf_model_type` and `re` imports.

Export (`hf_export_handlers.py`, `layerwise_export.py`,
`unified_export_hf.py`, `unified_export_hf_streaming.py`) imports these
names from the new module. The imports stay deferred, because
`modelopt.torch.quantization` imports `modelopt.torch.export` and
importing at module scope would risk an import cycle; the comments now
give that reason. The PTQ skill references (`unsupported-models.md`,
`checkpoint-validation.md`) now point agents at
`modelopt/torch/models/<model_type>/modeling_ptq.py` for model-specific
patches.

Rebasing onto #2649 also replaces the README's DBRX example of a
model-specific wrapper with Llama4's fused BMM experts.

`step3p7` also gets its own `modeling_ptq.py`, which imports the
Step-3.5 module: Step-3.7 remote-code checkpoints use the same
`MoELinear`, and today they are covered only because the HF plugin
imports every `modeling_ptq`. With its own module, a future loader that
imports PTQ modeling by model type finds it too.

### Usage

No API change. To add PTQ support for a new model, put its wrapper in
`modelopt/torch/models/<model_type>/modeling_ptq.py` and add
`<model_type>` to the import loop at the end of
`quantization/plugins/huggingface.py`.

### Testing

Each branch of the stack checked out and tested on `main` at 90ba9fb,
CPU, torch 2.11. With transformers 5.18: `pytest tests/unit/torch/models
tests/unit/torch/quantization tests/unit/torch/export
tests/unit/recipe`, 2372 passed, 1 skipped. With transformers 5.5 (the
new floor): `tests/unit/torch/models` plus `test_moe_linear.py` and
`test_huggingface.py`, 207 passed, 1 skipped. GPU tests are left to CI.

### Before your PR is "*Ready for review*"

- Is this change backward compatible?: ✅ Only private (`_`-prefixed)
names change module; public API and quantization behavior are unchanged.
- If you copied code from any other sources or added a new PIP
dependency, did you follow guidance in `CONTRIBUTING.md`: N/A
- Did you write any new necessary tests?: N/A (verbatim move; existing
tests re-pointed)
- Did you update
[Changelog](https://github.com/NVIDIA/Model-Optimizer/blob/main/CHANGELOG.rst)?:
N/A (internal refactor)
- Did you get Claude approval on this PR?: ❌

### Additional Information

Part of a 5-PR stack; see the series list above.

🤖 Generated with [Claude Code](https://claude.com/claude-code)



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added post-training quantization support for Step-family models with
expert-indexed MoE layers.
* Checkpoint exports preserve the original layout of quantized expert
weights and scales.
* **Documentation**
* Updated MoE architecture examples and guidance for configuring
model-specific quantization support, including Step model revisions.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
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