Chenjie LuoandClaude Opus 5 d69e93a72b Record the MLflow run that produced a checkpoint in .experiment.json (#2374)
### What does this PR do?

Type of change: new feature

A tracked `hf_ptq` run already tags itself with the checkpoint it writes
(`checkpoint_path`), so a run can be followed to its output. The reverse
was missing: given a checkpoint on disk, there was no way to find the
run that quantized it without searching the tracking server by path.

A tracked run now writes `.experiment.json` into `--export_path` naming
the experiment, the MLflow run id and the run URL, and uploads the same
bytes as the `experiment.json` artifact so a downloaded artifact set is
self-describing. `MlflowRunLogger` gains a `run_info` property carrying
that identity, with the tracking URI credential-masked the way `run_url`
already was.

Two deliberate behaviours:

- **Written from a `finally`**, so a run that crashes after export still
leaves the pointer behind.
- **Skipped when the export directory is absent** — a run that exported
nothing has nowhere to put it, and creating the directory would suggest
a checkpoint that does not exist. The artifact is still uploaded in that
case, so a failed run is traceable from the server side.

A failed local write warns and continues rather than failing the job,
consistent with the rest of the MLflow path. Only the main rank writes,
since the logger is inert on other ranks.

### Usage

```bash
python hf_ptq.py --pyt_ckpt_path Qwen/Qwen3.5-0.8B --qformat fp8 \
    --export_path /tmp/qwen35-fp8 --mlflow https://<your-mlflow-server>
```

```console
$ cat /tmp/qwen35-fp8/.experiment.json
{
  "tracking_uri": "https://<your-mlflow-server>",
  "experiment_name": "alice/hf_ptq/Qwen3.5-0.8B-fp8",
  "experiment_id": "36",
  "run_id": "7bec239a3a154970b062f3024a5ff20e",
  "run_name": "20260910-175422",
  "run_url": "https://<your-mlflow-server>/#/experiments/36/runs/7bec239a3a154970b062f3024a5ff20e"
}
```

```python
# checkpoint -> run
import json, mlflow
info = json.load(open("/tmp/qwen35-fp8/.experiment.json"))
mlflow.set_tracking_uri(info["tracking_uri"])
run = mlflow.get_run(info["run_id"])
```

### Testing

**Unit** — `tests/unit/torch/utils/test_mlflow.py` (61 passed):
`run_info` contents before/after the run opens, the defaulted run name
being reported rather than left blank, and credential masking of the
tracking URI.

**Example** — `tests/examples/hf_ptq/test_hf_ptq_args.py` (27 passed):
the file landing in the checkpoint and on the server with identical
content, the failed-run path, the no-export path, and untracked runs
writing nothing.

**Real runs**, 1x H200, `Qwen3.5-0.8B` FP8 PTQ,
`tensorrt-llm/release:1.3.0rc26`:

- Against a local MLflow server — checkpoint copy and uploaded artifact
byte-identical; artifacts on the run were `command.txt`,
`experiment.json`, `logs/hf_ptq.log`, `summary/quant_summary.txt`,
`version.txt`.
- Against the internal `mlflow-modelopt` server (experiment
`chenjiel/hf_ptq/Qwen3.5-0.8B-fp8`, run
`7bec239a3a154970b062f3024a5ff20e`) — same result, confirming artifact
upload against a real backend. Reading `.experiment.json` back and
calling `mlflow.get_run(run_id)` resolved to `FINISHED` with
`checkpoint_path` pointing at the export directory.
- Crash path exercised for real when a first attempt died on a gated
calibration dataset: no export directory created, `experiment.json`
still uploaded, run closed `FAILED`.

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

- Is this change backward compatible?: ✅
- 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](https://github.com/NVIDIA/Model-Optimizer/blob/main/CHANGELOG.rst)?:
✅ — new entry under `*Misc*` in the open 0.48.0 section, matching where
the MLflow entries sit in 0.47.0.
- Did you get Claude approval on this PR?: ❌

🤖 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**
* Exported checkpoints now record experiment and run traceability
metadata in `.experiment.json`.
* Checkpoint metadata is uploaded with opened MLflow runs, including
runs where export fails.
* Active MLflow run details—including identifiers, resolved run name,
URL, and tracking server—are available with credentials redacted.
* **Bug Fixes**
* Improved handling of failed, untracked, and pre-existing exports to
prevent inherited metadata pointers.
* **Documentation**
* Updated MLflow integration guidance and changelog information for
checkpoint metadata.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Chenjie Luo <chenjiel@nvidia.com>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-09-10 22:24:37 +00:00
2026-09-10 17:30:37 +00:00
2026-09-10 17:30:37 +00:00
2026-09-10 17:30:37 +00:00
2026-09-10 00:35:31 +08:00
2026-09-10 17:30:37 +00:00

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NVIDIA Model Optimizer

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NVIDIA Model Optimizer (referred to as Model Optimizer, or ModelOpt) is a library comprising state-of-the-art model optimization techniques including quantization, pruning, Neural Architecture Search (NAS), distillation, speculative decoding and sparsity to accelerate models.

[Input] Model Optimizer currently supports inputs of a Hugging Face, PyTorch or ONNX model.

[Optimize] Model Optimizer provides Python APIs for users to easily compose the above model optimization techniques and export an optimized quantized checkpoint. Model Optimizer is also integrated with NVIDIA Megatron-Bridge, Megatron-LM and Hugging Face Accelerate for training required inference optimization techniques.

[Export for deployment] Seamlessly integrated within the NVIDIA AI software ecosystem, the quantized checkpoint generated from Model Optimizer is ready for deployment in downstream inference frameworks like SGLang, TensorRT-LLM, TensorRT, or vLLM. The unified Hugging Face export API now supports both transformers and diffusers models.

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Install

To install stable release packages for Model Optimizer with pip from PyPI:

pip install -U nvidia-modelopt[all]

Model Optimizer will download and install additional third-party open source software projects. Review the license terms of these open source projects before use.

To install from source in editable mode with all development dependencies or to use the latest features, run:

# Clone the Model Optimizer repository
git clone git@github.com:NVIDIA/Model-Optimizer.git
cd Model-Optimizer

pip install -e .[dev]

You can also directly use NVIDIA container images, which have Model Optimizer pre-installed:

  • nvcr.io/nvidia/pytorch:<version>-py3
  • nvcr.io/nvidia/nemo:<version>
  • nvcr.io/nvidia/tensorrt-llm/release:<version>

Before pulling and using the container images, please review their respective license terms. Make sure to upgrade Model Optimizer to the latest version as described above. Visit our installation guide for more fine-grained control on installed dependencies or for alternative docker images and environment variables to setup.

Techniques

Technique Description Examples Docs
Post Training Quantization Compress model size by 2x-4x, speeding up inference while preserving model quality! [HF LLMs / VLMs] [Megatron-Bridge LLMs / VLMs] [Diffusers] [ONNX] [Windows] [docs]
Quantization Aware Training / Distillation Refine accuracy of quantized models even further with a few training steps! [Hugging Face] [Megatron-Bridge] [docs]
Pruning Reduce your model parameters or memory footprint and accelerate inference by removing unnecessary weights! [General] [Megatron-Bridge]
Distillation Reduce deployment model size by teaching small models to behave like larger models! [Hugging Face] [Megatron-Bridge] [Megatron-LM] [docs]
Speculative Decoding Train draft modules to predict extra tokens during inference! [Hugging Face] [Megatron-LM] [docs]
Sparsity Efficiently compress your model by storing only its non-zero parameter values and their locations [Hugging Face] [docs]

Pre-Quantized Checkpoints

Resources

Model Support Matrix

Model Type Support Matrix
LLM / VLM Quantization View Support Matrix
Diffusers Quantization View Support Matrix
ONNX Quantization View Support Matrix
Windows Quantization View Support Matrix
Quantization Aware Training View Support Matrix
Pruning View Support Matrix
Distillation View Support Matrix
Speculative Decoding View Support Matrix

Deprecation Policy

Model Optimizer follows a structured approach to managing deprecated features:

  • Communication: Deprecation notices are documented in the Changelog. Deprecated items include source code statements indicating deprecation timing, with runtime warnings issued upon use.
  • Migration Period: Since Model Optimizer is still pre-1.0, we provide a 1-release (~1-month) migration period after deprecation. During this window, deprecated features continue functioning while issuing warnings.
  • Scope: The policy addresses both complete deprecations (entire APIs removed) and partial ones (specific parameters removed while methods remain).
  • Removal: Following the migration period, deprecated elements are removed in alignment with semantic versioning standards, potentially including breaking changes in minor version updates while Model Optimizer remains in 0.x.

Citation

If you use NVIDIA Model Optimizer in your research, please cite it as follows:

@misc{nvidia-modelopt,
  author       = {{NVIDIA Corporation}},
  title        = {{NVIDIA Model Optimizer}},
  howpublished = {\url{https://github.com/NVIDIA/Model-Optimizer}},
  year         = {2024--2026},
  note         = {GitHub repository}
}

Contributing

Model Optimizer is now open source! We welcome any feedback, feature requests and PRs. Please read our Contributing guidelines for details on how to contribute to this project.

AI Agents

ModelOpt's agent skills can be installed from this repository and used in any workspace.

Claude Code

claude plugin marketplace add https://github.com/NVIDIA/Model-Optimizer.git
claude plugin install modelopt@modelopt

Codex

codex plugin marketplace add https://github.com/NVIDIA/Model-Optimizer.git

Then open /plugins, select the modelopt marketplace, and install modelopt. Contributors can also use the skills directly from a checkout. See the agent tooling notes.

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