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[OMNIML-6028] [3/5] hf_ptq: load the model from local disk, downloading it first if needed - #2609

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@shengliangxu shengliangxu commented Sep 30, 2026 •

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What does this PR do?

Type of change: bug fix

Summary of the series

Every pipeline that quantizes, prunes, sparsifies or distills a Hugging Face model now starts the same way: make the checkpoint local, then load from it. ensure_local_checkpoint returns a local directory as-is and downloads a Hub model ID in full if it is not cached yet -- once, on rank 0 -- and the model, tokenizer and processor are then loaded from that local directory.

Before, a Hub ID went straight to from_pretrained, which fetched only the files loading needed, so every later step that needed the source as files found its own way back to it: hf_ptq through a hand-rolled cache lookup (_resolve_model_path, whose TRANSFORMERS_CACHE glob picked the lexicographically largest commit hash rather than refs/main) and a hardcoded download allowlist, regenerating tokenizer files along the way; the Megatron export by fetching only *.py for a Hub ID; other callers of export_hf_checkpoint not at all.

With the source on local disk, exports follow one rule: an export writes the model files -- weights in any format and the metadata describing them -- and carries every other source file (non-model files: tokenizer, processor, remote code, chat templates, README, ...) over verbatim, from local disk only.

Merge in order:

  1. [OMNIML-6027] [1/5] Add ensure_local_checkpoint to load models from local disk, and copy_non_model_files #2607 — Add ensure_local_checkpoint to load models from local disk, and copy_non_model_files
  2. [OMNIML-6031] [2/5] HF exporters write off-index safetensors and non-model files #2608 — HF exporters write off-index safetensors and non-model files
  3. [OMNIML-6028] [3/5] hf_ptq: load the model from local disk, downloading it first if needed #2609 — hf_ptq: load the model from local disk, downloading it first if needed ← this PR
  4. [5/5] megatron_bridge: load the HF model from local disk; Megatron export copies its non-model files #2610 — megatron_bridge: load the HF model from local disk; Megatron export copies its non-model files
  5. [OMNIML-6029] [4/5] llm_sparsity: load the model from local disk, downloading it first if needed #2611 — llm_sparsity: load the model from local disk, downloading it first if needed

This PR [3/5]

Loading. main() now makes the model local before anything else: ensure_local_checkpoint(--pyt_ckpt_path) returns a local directory as-is or downloads a Hub ID once, and every later step -- loading the model, tokenizer and processor, the MXFP4 cast, and the export's copy of the source's files -- reads that local copy. --pyt_ckpt_path stays as given; the local directory is args.local_checkpoint_path, and args.hub_model_id (the Hub ID, or None) still names the layerwise resume directory. This replaces the per-step ways back to the source -- _resolve_model_path, a hardcoded sidecar allowlist, _resolved_local_dir, hf_hub_download fallbacks.

Exporting. The unified exporters copy the source's non-model files themselves (#2608), so the example no longer does -- except after the deprecated TensorRT-LLM export, which does not. It also stops regenerating tokenizer and processor files: the source's are carried over verbatim. So a pad_token that get_tokenizer sets for calibration (the EOS token, for a model without one) no longer leaks into the exported tokenizer; #2597 already stopped it overwriting an existing pad token. It also removes the default padding side and pad token threaded through six functions only to undo that before saving.

The three notebooks do the same: make the model local first, load from it, and leave the tokenizer files to the export. Mostly deletions (+84 / −466).

Usage

No flag change. --pyt_ckpt_path org/model downloads the whole repo once before loading; to skip files, download it yourself (e.g. hf download org/model --exclude 'original/*') and pass the local path.

Testing

Same suite as #2607: 685 passed (the hf_ptq tests moved to the library in #2607 or were dropped with the code they covered). Notebooks validated as JSON. CPU only (torch 2.12, transformers 5.9, huggingface_hub 1.19); transformer_engine cannot be imported in this environment, so GPU and Megatron tests are left to CI.

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Make sure you read and follow the Security Best Practices (e.g. avoiding hardcoded trust_remote_code=True, torch.load(..., weights_only=False), pickle, etc.).

Additional Information

Stacked on #2608.

Summary by CodeRabbit

  • Updates
    • Models and tokenizers are loaded from a locally resolved checkpoint, which is reused across quantization and export steps.
    • TensorRT-LLM exports include non-model files from the local checkpoint, and multimodal exports save the source configuration.
    • Quantized exports no longer separately save tokenizer files or restore tokenizer padding settings. Local checkpoint paths are also used when restoring compressed weights and resolving source configurations.

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📝 Walkthrough

Walkthrough

HF PTQ resolves input checkpoints to local paths for model and tokenizer loading. Export handling uses the local checkpoint for source-file operations. Export calls no longer restore or save tokenizer state separately.

Changes

HF PTQ checkpoint and export flow

Layer / File(s) Summary
Resolve and load local checkpoints
examples/hf_ptq/example_utils.py, examples/hf_ptq/hf_ptq.py, examples/hf_ptq/notebooks/*, tests/examples/hf_ptq/test_hf_ptq_args.py, tests/examples/hf_ptq/test_hf_ptq_vision_quantization.py
The PTQ entry point resolves the input checkpoint and uses its local path for model, tokenizer, and checkpoint reads. Utility checks, notebook loading, and test fixtures use the local checkpoint fields.
Update export handling
examples/hf_ptq/example_utils.py, examples/hf_ptq/hf_ptq.py, examples/hf_ptq/notebooks/*, tests/examples/hf_ptq/*
Export calls no longer pass tokenizer padding defaults or save the tokenizer separately. Multimodal exports save the source config, and TensorRT-LLM exports copy non-model files from the local checkpoint. Tests and notebook export steps reflect these changes.

Priority: ⬇️ Low

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

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant PTQMain
  participant ensure_local_checkpoint
  participant ModelAndTokenizer
  PTQMain->>ensure_local_checkpoint: Resolve input checkpoint
  ensure_local_checkpoint-->>PTQMain: Return Hub ID and local path
  PTQMain->>ModelAndTokenizer: Load model and tokenizer from local path
Loading

Merge Risk: ⚪ Minimal · up to 26563

No merge-blocking issue is established for these test changes; they are ready for normal checks.

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 warning)

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✅ Passed checks (5 passed)
Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check ✅ Passed The title clearly summarizes the main change: load the model from a local checkpoint, downloading it when needed.
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 PR changes Python files under examples/hf_ptq and its tests, plus three notebooks. The added-code scan found no `torch.load(..., weights_only=Fals…
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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.15%. Comparing base (5b06081) to head (265631c).

Additional details and impacted files
@@            Coverage Diff             @@
##             main    #2609      +/-   ##
==========================================
- Coverage   72.16%   72.15%   -0.01%     
==========================================
  Files         635      635              
  Lines       70643    70643              
==========================================
- Hits        50977    50970       -7     
- Misses      19666    19673       +7     
Flag Coverage Δ
examples-gpt-oss 13.45% <ø> (+0.12%) ⬆️
examples-hf_ptq 23.34% <ø> (+0.11%) ⬆️
examples-llm_distill 13.52% <ø> (+0.12%) ⬆️
examples-llm_eval 17.29% <ø> (+0.03%) ⬆️
examples-llm_qat 17.52% <ø> (+0.10%) ⬆️
examples-llm_sparsity 15.82% <ø> (+0.11%) ⬆️
examples-specdec_bench 13.23% <ø> (+0.12%) ⬆️
examples-speculative_decoding 17.59% <ø> (-0.21%) ⬇️
unit 59.59% <ø> (-0.01%) ⬇️

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@shengliangxu
shengliangxu force-pushed the shengliangx/model-download-3-hf-ptq branch 2 times, most recently from b7e35e3 to 27857e6 Compare October 1, 2026 22:02
@shengliangxu shengliangxu changed the title [3/5] hf_ptq: load from a local checkpoint, carry its files verbatim [3/5] hf_ptq: load the model from local disk, downloading it first if needed Oct 1, 2026
@shengliangxu
shengliangxu force-pushed the shengliangx/model-download-3-hf-ptq branch from 27857e6 to 213ed0e Compare October 2, 2026 01:41
@shengliangxu
shengliangxu force-pushed the shengliangx/model-download-3-hf-ptq branch from 213ed0e to 0b6a3f4 Compare October 5, 2026 21:26
@shengliangxu
shengliangxu force-pushed the shengliangx/model-download-3-hf-ptq branch 3 times, most recently from 2ce59dd to 2d21f50 Compare October 6, 2026 21:02
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shengliangxu force-pushed the shengliangx/model-download-3-hf-ptq branch from 2d21f50 to ebf6f65 Compare October 7, 2026 00:17
shengliangxu added a commit that referenced this pull request Oct 7, 2026
… copy_non_model_files (#2607)

### What does this PR do?

Type of change: new feature

### Summary of the series

Every pipeline that quantizes, prunes, sparsifies or distills a Hugging
Face model now starts the same way: **make the checkpoint local, then
load from it**. `ensure_local_checkpoint` returns a local directory
as-is and downloads a Hub model ID in full if it is not cached yet --
once, on rank 0 -- and the model, tokenizer and processor are then
loaded from that local directory.

Before, a Hub ID went straight to `from_pretrained`, which fetched only
the files loading needed, so every later step that needed the source as
files found its own way back to it: `hf_ptq` through a hand-rolled cache
lookup (`_resolve_model_path`, whose `TRANSFORMERS_CACHE` glob picked
the lexicographically largest commit hash rather than `refs/main`) and a
hardcoded download allowlist, regenerating tokenizer files along the
way; the Megatron export by fetching only `*.py` for a Hub ID; other
callers of `export_hf_checkpoint` not at all.

With the source on local disk, exports follow one rule: an export writes
the **model files** -- weights in any format and the metadata describing
them -- and carries every other source file (**non-model files**:
tokenizer, processor, remote code, chat templates, README, ...) over
verbatim, from **local disk only**.

Merge in order:

1. #2607 — Add `ensure_local_checkpoint` to load models from local disk,
and `copy_non_model_files` ← **this PR**
2. #2608 — HF exporters write off-index safetensors and non-model files
3. #2609 — `hf_ptq`: load the model from local disk, downloading it
first if needed
4. #2610 — `megatron_bridge`: load the HF model from local disk;
Megatron export copies its non-model files
5. #2611 — `llm_sparsity`: load the model from local disk, downloading
it first if needed

### This PR [1/5]

Adds the two building blocks to
`modelopt/torch/utils/plugins/hf_checkpoint_utils.py`, re-exported from
`modelopt.torch.export`. Nothing calls them yet; #2609–#2611 make
`ensure_local_checkpoint` the first step of each pipeline.

- **`ensure_local_checkpoint(model_name_or_path, group=None) ->
(hub_model_id, local_checkpoint_path)`** makes the whole checkpoint
local before anything loads it: a local directory as-is, a Hub ID
downloaded in full if not cached yet (guessing which files are redundant
would risk dropping ones the checkpoint needs). Load the model,
tokenizer and processor from `local_checkpoint_path`; `hub_model_id` is
the Hub ID, or `None` for a local path, for records that must stay valid
on other hosts.
- Under `torch.distributed`, rank 0 of `group` resolves it and
broadcasts the result -- or its error, so a failed download raises
everywhere rather than stranding the waiting ranks. Rank 0 decides for
local paths too, since ranks checking for themselves could disagree
about a node-local directory. Without a `group`, every rank waits on a
temporary gloo group whose 24 h timeout outlasts a large download; with
one, the caller's group carries the wait. A rank that cannot see the
resolved path raises, asking for shared storage.
- `snapshot_download` silently returns a possibly incomplete cached
snapshot when the Hub is unreachable. With `HF_HUB_OFFLINE` the cache is
used quietly (the user's choice); with the Hub unexpectedly unreachable
it is used with a warning, or the Hub's error is raised if nothing is
cached. An input that is neither a local directory nor a Hub model ID
the Hub can access -- a mistyped local path, say -- raises a
`ValueError` saying so, chained to the Hub's error; a gated repo still
raises `GatedRepoError`.
- **`copy_non_model_files(source, export_dir)`** copies every file of a
local checkpoint, recursively, except weight files in any format,
top-level export metadata (`config.json`, `hf_quant_config.json`, stale
quant configs, `.experiment.json`), files the export already wrote,
hidden directories (`.git`, `.cache`), and links that resolve outside
the checkpoint or its Hub `blobs/` (checked with the existing
`resolve_checkpoint_file`). It never writes through a link already in
the export, removes a partial copy when one fails, and skips
`export_dir` when it lies inside the source (e.g. an earlier export). It
returns `/`-separated paths on every platform.

**What happens to the existing copy helpers.** `copy_non_model_files`
replaces both copy rules the series' callers use today. #2609 moves
`hf_ptq` off `copy_non_safetensor_files_from_ckpt`. #2610 moves the
Megatron export onto `copy_non_model_files` (dropping its Hub-fetching
`copy_hf_ckpt_remote_code` branch), moves `prune_minitron` and
`export_distilled_megatron_to_hf` off `copy_hf_ckpt_remote_code`, and
deprecates `copy_non_safetensor_files_from_ckpt`.
`copy_hf_ckpt_remote_code` stays for now: puzzletron's
`init_child_from_parent` still uses it, and migrating puzzletron is out
of scope for this series.

Also: module constants move to the top next to a note defining model
versus non-model files; `off_index_safetensors_files` /
`copy_off_index_safetensors` accept a `None` source and report what they
copy; comments stop calling off-index weight files "sidecars".

### Usage

```python
from modelopt.torch.export import copy_non_model_files, ensure_local_checkpoint

hub_model_id, local_checkpoint_path = ensure_local_checkpoint("Qwen/Qwen3-8B")  # every rank calls it
model = AutoModelForCausalLM.from_pretrained(local_checkpoint_path)
...
copy_non_model_files(local_checkpoint_path, export_dir)  # after the export wrote its own files
```

### Testing

`pytest tests/unit/torch/utils tests/unit/torch/export
tests/examples/hf_ptq` (GPU end-to-end and `test_dataset_utils`
excluded): 684 passed. New tests cover the copy rule (weights, owned
metadata, subdirectories, hidden dirs, links inside/outside/dangling,
Hub `blobs/`), online/offline/unreachable/missing-repo resolution, and
-- over two real gloo processes -- rank-0-only download, error
propagation, an explicit group, a subgroup without global rank 0, and a
local path hidden from one rank. The resolution paths were also checked
live against the Hub. CPU only (torch 2.12, transformers 5.9,
huggingface_hub 1.19); `transformer_engine` cannot be imported in this
environment, so GPU and Megatron tests are left to CI.

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

Make sure you read and follow [Contributor
guidelines](https://github.com/NVIDIA/Model-Optimizer/blob/main/CONTRIBUTING.md)
and your commits are signed (`git commit -s -S`).

Make sure you read and follow the [Security Best
Practices](https://github.com/NVIDIA/Model-Optimizer/blob/main/SECURITY.md#security-coding-practices-for-contributors)
(e.g. avoiding hardcoded `trust_remote_code=True`, `torch.load(...,
weights_only=False)`, `pickle`, etc.).

- Is this change backward compatible?: ✅ (additive)
- 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)?:
N/A (entries land with the behaviour changes in #2608–#2610)
- Did you get Claude approval on this PR?: ❌

### Additional Information

Stacked series; this is the base.





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

* **New Features**
* Checkpoint exports can resolve local and Hub-hosted checkpoints, using
cached snapshots when offline or Hub access is unavailable. Missing
offline cache entries are reported as errors.
* Exports can copy eligible non-model checkpoint files without
overwriting existing export files. Hidden directories and unsafe or
dangling links are excluded.
* Distributed exports coordinate checkpoint resolution across processes
and report failures, including when other processes cannot access the
resolved path.
* Safetensors files not listed in an index are treated as standalone
weight files and can be copied into exports when eligible.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
@shengliangxu
shengliangxu marked this pull request as ready for review October 7, 2026 05:59
@shengliangxu
shengliangxu requested review from a team as code owners October 7, 2026 05:59
@shengliangxu
shengliangxu force-pushed the shengliangx/model-download-3-hf-ptq branch from ebf6f65 to a01879b Compare October 7, 2026 06:05
Base automatically changed from shengliangx/model-download-2-hf-exporters to main October 7, 2026 07:59
shengliangxu added a commit that referenced this pull request Oct 7, 2026
…2608)

### What does this PR do?

Type of change: bug fix, new feature

### Summary of the series

Every pipeline that quantizes, prunes, sparsifies or distills a Hugging
Face model now starts the same way: **make the checkpoint local, then
load from it**. `ensure_local_checkpoint` returns a local directory
as-is and downloads a Hub model ID in full if it is not cached yet --
once, on rank 0 -- and the model, tokenizer and processor are then
loaded from that local directory.

Before, a Hub ID went straight to `from_pretrained`, which fetched only
the files loading needed, so every later step that needed the source as
files found its own way back to it: `hf_ptq` through a hand-rolled cache
lookup (`_resolve_model_path`, whose `TRANSFORMERS_CACHE` glob picked
the lexicographically largest commit hash rather than `refs/main`) and a
hardcoded download allowlist, regenerating tokenizer files along the
way; the Megatron export by fetching only `*.py` for a Hub ID; other
callers of `export_hf_checkpoint` not at all.

With the source on local disk, exports follow one rule: an export writes
the **model files** -- weights in any format and the metadata describing
them -- and carries every other source file (**non-model files**:
tokenizer, processor, remote code, chat templates, README, ...) over
verbatim, from **local disk only**.

Merge in order:

1. #2607 — Add `ensure_local_checkpoint` to load models from local disk,
and `copy_non_model_files`
2. #2608 — HF exporters write off-index safetensors and non-model files
← **this PR**
3. #2609 — `hf_ptq`: load the model from local disk, downloading it
first if needed
4. #2610 — `megatron_bridge`: load the HF model from local disk;
Megatron export copies its non-model files
5. #2611 — `llm_sparsity`: load the model from local disk, downloading
it first if needed

### This PR [2/5]

`export_hf_checkpoint` put the tensors of off-index safetensors
(GLM-4.7's `mtp.safetensors`) into `exclude_modules` but left copying
the files to the `hf_ptq` example, so any other caller exported
exclusions for weights the checkpoint lacked. It likewise left the
source's non-model files to the caller, while its streaming paths copied
only top-level `*.py`.

Every HF export path now does both itself, from the model's source
checkpoint on local disk: the regular, streaming and FSDP2 paths; the
layerwise path, into the exporter's own directory (a recipe's
`layerwise.export_dir` can set it apart from `export_dir`); and the vLLM
fake-quant export. `save_non_weight_artifacts` copies the non-model
files in place of its `*.py` glob. A Hub-ID source gets a warning
instead of a fetch, since its cache holds only what loading needed.

Until #2609, `hf_ptq` still runs its own copy afterwards -- harmless, as
files already present are skipped -- and prints that warning for a
Hub-ID `--pyt_ckpt_path`.

### Usage

No API change; `export_hf_checkpoint(model, export_dir=...)` on a model
loaded from a local directory now also writes the source's non-model and
off-index files.

### Testing

Same suite as #2607: 688 passed. New tests: the regular path copies
non-model files (tiny Llama loaded from a local directory), a Hub-ID
source warns without fetching, and the layerwise path writes
`mtp.safetensors` into the exporter's directory even when `export_dir`
differs. A CPU end-to-end FP8 export of
`hf-internal-testing/tiny-random-LlamaForCausalLM` carried the tokenizer
and README. CPU only (torch 2.12, transformers 5.9, huggingface_hub
1.19); `transformer_engine` cannot be imported in this environment, so
GPU and Megatron tests are left to CI.

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

Make sure you read and follow [Contributor
guidelines](https://github.com/NVIDIA/Model-Optimizer/blob/main/CONTRIBUTING.md)
and your commits are signed (`git commit -s -S`).

Make sure you read and follow the [Security Best
Practices](https://github.com/NVIDIA/Model-Optimizer/blob/main/SECURITY.md#security-coding-practices-for-contributors)
(e.g. avoiding hardcoded `trust_remote_code=True`, `torch.load(...,
weights_only=False)`, `pickle`, etc.).

- Is this change backward compatible?: ✅ (exports gain files; nothing is
removed)
- 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)?:
✅
- Did you get Claude approval on this PR?: ❌

### Additional Information

Stacked on #2607.




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

* **Bug Fixes**
* Hugging Face and vLLM exports now preserve off-index safetensors and
other non-model files from local source checkpoints, including files not
listed in the checkpoint index.
* Layerwise exports place copied safetensors in the correct output
directory.
* Exports from Hub sources warn when source files cannot be copied
locally, without downloading them.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
A Hub model ID reached the loader as-is, so every later step that needed
the source checkpoint as files had its own way back to a directory:
_resolve_model_path (whose TRANSFORMERS_CACHE glob picked the
lexicographically largest commit hash rather than refs/main), a hardcoded
sidecar allowlist, _resolved_local_dir, and hf_hub_download fallbacks.
Now main() calls ensure_local_checkpoint once, leaving --pyt_ckpt_path as
given and storing hf_model_path (the local copy every step reads) and
hf_model_name (the Hub ID, or None). The layerwise resume directory is
still named after the Hub ID.

The unified exporters copy the source's non-model files themselves, so
the example no longer does -- except after the deprecated TensorRT-LLM
export, which does not. It also stops regenerating tokenizer and
processor files: the source's are carried over verbatim. That fixes
exports shipping pad_token set to the EOS token, which get_tokenizer sets
for calibration, and removes the default padding side and pad token
threaded through six functions only to undo that before saving. The
notebooks do the same.

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

hf_model_path read as a Hub path when it is the local directory, and
hf_model_name did not say it is the Hub identifier; name both for what
they are.

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

test_hf_ptq_model_type, new on main, still passed default_padding_side and
default_pad_token, which this branch removes from post_quantize.

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
@shengliangxu
shengliangxu force-pushed the shengliangx/model-download-3-hf-ptq branch from a01879b to c61b877 Compare October 7, 2026 07:59

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

Nudge: the shared helpers are well tested, but the new hf_ptq orchestration lacks a regression test.

Needs action:

  • Add a mocked Hub-ID regression in tests/examples/hf_ptq/test_hf_ptq_args.py proving main() resolves the checkpoint before loading, preserves pyt_ckpt_path, and passes the local path through loading and TensorRT-LLM sidecar copying.

No action needed:

  • Existing test edits are justified: removed tests cover deleted helpers, the library tests cover their replacements, and argument updates follow the changed signatures.
  • The change reuses the checkpoint utilities and unified exporters rather than introducing duplicate logic. Tests were inspected, not executed.

…LM export copies from it

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

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@cjluo-nv bot review: added the regression tests in 265631c (tests/examples/hf_ptq/test_hf_ptq_args.py):

  • test_main_makes_a_hub_checkpoint_local_before_loading calls main() with --pyt_ckpt_path org/model and a fake ensure_local_checkpoint. It asserts that ensure_local_checkpoint runs before load_model, that pyt_ckpt_path stays org/model, and that load_model gets hub_model_id="org/model" plus the local directory.
  • test_tensorrt_llm_export_copies_non_model_files_from_the_local_copy runs export_quantized on the TensorRT-LLM path and asserts that copy_non_model_files(local_checkpoint_path, export_path) is called with the local directory.

Each test fails when the corresponding wiring is broken: copying from pyt_ckpt_path, or skipping ensure_local_checkpoint.

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

LGTM: the prior orchestration-test concern is resolved; human sign-off remains required for the justified existing-test removals and updates.

Needs action:

  • Confirm the existing-test edits: removed cases cover deleted helpers, shared-library tests cover their replacements, and signature updates follow the changed behavior.

No action needed:

  • ✔️ Resolved since the last review: new mocked regressions verify checkpoint resolution before loading, preservation of the Hub ID, and TensorRT-LLM sidecar copying from the local directory.
  • Tests inspected, not executed.

@shengliangxu
shengliangxu requested a review from meenchen October 7, 2026 16:37
Comment thread examples/hf_ptq/hf_ptq.py
# --pyt_ckpt_path stays as given. Every later step reads the local copy of the whole
# checkpoint in local_checkpoint_path; hub_model_id is the Hub ID, or None for a local
# path.
args.hub_model_id, args.local_checkpoint_path = ensure_local_checkpoint(

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ensure_local_checkpoint: will it point to the local HF downloaded cache or download the model to a particular location like /tmp?

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It uses the local Hugging Face cache. It calls snapshot_download with no cache_dir/local_dir, so files land in the standard hub cache (HF_HUB_CACHE, default ~/.cache/huggingface/hub, following HF_HOME), and it returns the snapshot directory there (.../models--org--name/snapshots/<commit>). Nothing goes to /tmp, and a local directory is returned as-is.

If the model is already in the cache, it is not downloaded again: the cached snapshot is used directly, and only files missing from it are fetched.

The download behavior is the same as before this PR: from_pretrained("org/model") already downloaded into this same cache. The only difference is that this is now an explicit first step of the pipeline, before any loading. It makes the whole checkpoint local up front, instead of each later step (model, tokenizer, processor, export) fetching what it needs on its own.

Under torch.distributed, rank 0 does the download and the other ranks use the same path. The cache therefore has to be on storage every node can see; if a rank can't see the path, it raises with a hint.

@shengliangxu
shengliangxu merged commit d752561 into main Oct 7, 2026
44 checks passed
@shengliangxu
shengliangxu deleted the shengliangx/model-download-3-hf-ptq branch October 7, 2026 17:46
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PR Preview Action v1.8.1
Preview removed because the pull request was closed.
2026-10-07 17:46 UTC

shengliangxu added a commit that referenced this pull request Oct 7, 2026
…rst if needed (#2611)

### What does this PR do?

Type of change: bug fix

### Summary of the series

Every pipeline that quantizes, prunes, sparsifies or distills a Hugging
Face model now starts the same way: **make the checkpoint local, then
load from it**. `ensure_local_checkpoint` returns a local directory
as-is and downloads a Hub model ID in full if it is not cached yet --
once, on rank 0 -- and the model, tokenizer and processor are then
loaded from that local directory.

Before, a Hub ID went straight to `from_pretrained`, which fetched only
the files loading needed, so every later step that needed the source as
files found its own way back to it: `hf_ptq` through a hand-rolled cache
lookup (`_resolve_model_path`, whose `TRANSFORMERS_CACHE` glob picked
the lexicographically largest commit hash rather than `refs/main`) and a
hardcoded download allowlist, regenerating tokenizer files along the
way; the Megatron export by fetching only `*.py` for a Hub ID; other
callers of `export_hf_checkpoint` not at all.

With the source on local disk, exports follow one rule: an export writes
the **model files** -- weights in any format and the metadata describing
them -- and carries every other source file (**non-model files**:
tokenizer, processor, remote code, chat templates, README, ...) over
verbatim, from **local disk only**.

Merge in order:

1. #2607 — Add `ensure_local_checkpoint` to load models from local disk,
and `copy_non_model_files`
2. #2608 — HF exporters write off-index safetensors and non-model files
3. #2609 — `hf_ptq`: load the model from local disk, downloading it
first if needed
4. #2611 — `llm_sparsity`: load the model from local disk, downloading
it first if needed ← **this PR**
5. #2610 — `megatron_bridge`: load the HF model from local disk;
Megatron export copies its non-model files

### This PR [4/5]

**Loading.** `hf_sa.py` and `export_hf_ckpt.py` now make the model local
first with `ensure_local_checkpoint` -- a local directory as-is, a Hub
ID downloaded once -- and load the model and tokenizer from that copy
(`args.local_checkpoint_path`), keeping their argument as given. That is
also what lets `export_hf_checkpoint`, which carries the source's
non-model files only from local disk (#2608), include them.

**Exporting.** `hf_sa.py` no longer saves its tokenizer into the export:
it sets `pad_token` to EOS only for generation, so the source's files
are the right ones. `export_hf_ckpt.py` keeps its save, after the
export, because it can add a pad token and resize the embeddings.

### Usage

No flag change.

### Testing

Both scripts byte-compile; their end-to-end tests need a GPU and are
left to CI. No library code changes in this PR.

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

Make sure you read and follow [Contributor
guidelines](https://github.com/NVIDIA/Model-Optimizer/blob/main/CONTRIBUTING.md)
and your commits are signed (`git commit -s -S`).

Make sure you read and follow the [Security Best
Practices](https://github.com/NVIDIA/Model-Optimizer/blob/main/SECURITY.md#security-coding-practices-for-contributors)
(e.g. avoiding hardcoded `trust_remote_code=True`, `torch.load(...,
weights_only=False)`, `pickle`, etc.).

- 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?: N/A
- Did you update
[Changelog](https://github.com/NVIDIA/Model-Optimizer/blob/main/CHANGELOG.rst)?:
N/A (no user-facing change beyond the series' entries in #2608 and
#2610)
- Did you get Claude approval on this PR?: ❌

### Additional Information

Based on `main` (#2607–#2609 are merged); #2610 is stacked on it.






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

* **Improvements**
* Model export examples load checkpoints from a local copy while
retaining the original model reference and, when available, its Hub ID.
* Weight-sparsity exports save tokenizer updates, including
padding-token changes. Attention-sparsity exports no longer save the
tokenizer separately.
  * Attention-sparsity exports run the model in inference mode.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Shengliang Xu <shengliangx@nvidia.com>
@shengliangxu shengliangxu changed the title [3/5] hf_ptq: load the model from local disk, downloading it first if needed [OMNIML-6028] [3/5] hf_ptq: load the model from local disk, downloading it first if needed Oct 9, 2026
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