[Tracing] Onload sequential ancestors (#1690)

## Background ##
The idea of tracing is to capture all of the events and operations that
happen during a model's execution. However, some operations are too
complex to capture in the graph. One of these skipped operations is the
onloading/offloading of weights because this operation is too
complicated to captured by torch dynamo.

```
    parent
|            \
seq_target   weight
```

The problem is that, if we skip onloading/offloading during graph
capture, weights which appear in the graph might not be onloaded at
execution time. This isn't a problem for weights which are equal to/
high granularity than the sequential targets, since those weights belong
to modules which are called by the graph (and therefore trigger hooks).

```
hidden_states = ...
... = self.decoder_layer(hidden_states)   # module call triggers onloading hooks
```

```
hidden_states = ...
hidden_states = hidden_states + self.bias  # self.bias might not be onloaded
                                           # we never captured the onloading hook in the graph
```

### Big Code ###
The GPT Big Code model is the first model we've seen like this, where it
contains a parameter directly attached to a module which is a caller
(ancestor) of the sequential targets. It has this extra, [directly
attached bias
parameter](https://github.com/huggingface/transformers/blob/main/src/transformers/models/gpt_bigcode/modeling_gpt_bigcode.py#L416-L418).

```
 GPTBigCodeModel
|                \
GPTBigCodeBlock   bias
```

## Purpose ##
* Support models which have call graph ancestors with directly attached
parameters

## Changes ##
* Change the policy for these kinds of modules. Instead of skipping the
tracing of their internals, instead just onload them, as they are
unlikely to have a large number of direct parameters.

## Testing ##
* Added big code to tracing tests
* Ran big code example script to completion

<details><summary>example_script.py</summary>

```python3
from transformers import AutoModelForCausalLM, AutoTokenizer
from llmcompressor.modifiers.quantization import GPTQModifier
from llmcompressor.transformers import oneshot
from datasets import load_dataset

# Load model
model_stub = "ibm-granite/granite-20b-code-instruct-8k"
model_name = model_stub.split("/")[-1]

num_samples = 1024
max_seq_len = 8192

tokenizer = AutoTokenizer.from_pretrained(model_stub)

model = AutoModelForCausalLM.from_pretrained(
    model_stub,
    device_map="auto",
    torch_dtype="auto",
)

def preprocess_fn(example):
  return {"text": example["text"]} #, add_generation_prompt=False, tokenize=False)}

ds = load_dataset("neuralmagic/LLM_compression_calibration", split="train")
ds = ds.map(preprocess_fn)

def tokenize(sample):
    return tokenizer(
        sample["text"],
        padding=False,
        truncation=False,
        add_special_tokens=True,
    )

ds = ds.map(tokenize, remove_columns=ds.column_names)

# Configure the quantization algorithm and scheme
recipe = GPTQModifier(
    targets="Linear",
    scheme="W4A16",
    ignore=["lm_head"],
    sequential_targets=["GPTBigCodeBlock"],
    dampening_frac=0.01,
)

# Apply quantization
oneshot(
    model=model,
    dataset=ds,
    recipe=recipe,
    max_seq_length=max_seq_len,
    num_calibration_samples=num_samples,
)

# Save to disk in compressed-tensors format
save_path = model_name + "-quantized.w4a16"
model.save_pretrained(save_path)
tokenizer.save_pretrained(save_path)
print(f"Model and tokenizer saved to: {save_path}")
```

</details>

---------

Signed-off-by: Kyle Sayers <[email protected]>

Author: kylesayrs

src/llmcompressor/modifiers/awq/mappings.py

@@ -133,18 +133,9 @@ class AWQMapping:
 ]
 
 _bloom_mappings = [
-    AWQMapping(
-        "re:.*input_layernorm$",
-        ["re:.*query_key_value$"]
-    ),
-    AWQMapping(
-        "re:.*post_attention_layernorm$",
-        ["re:.*dense_h_to_4h$"]
-    ),
-    AWQMapping(
-        "re:.*gelu_impl$",
-        ["re:.*dense_4h_to_h$"]
-    ),
+    AWQMapping("re:.*input_layernorm$", ["re:.*query_key_value$"]),
+    AWQMapping("re:.*post_attention_layernorm$", ["re:.*dense_h_to_4h$"]),
+    AWQMapping("re:.*gelu_impl$", ["re:.*dense_4h_to_h$"]),
     # Note: AutoAWQ excludes this mapping, based on researcher's post in
     # https://github.com/mit-han-lab/llm-awq/issues/2#issuecomment-1606297469
     # AWQMapping(

src/llmcompressor/pipelines/sequential/helpers.py

@@ -5,6 +5,7 @@
 from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Set, Tuple
 
 import torch
+from accelerate.hooks import remove_hook_from_module
 from compressed_tensors.quantization import find_name_or_class_matches
 from compressed_tensors.utils import (
     has_offloaded_params,
@@ -177,13 +178,12 @@ def __init__(self, ancestors: Set[Module], offloaded: Set[Module]):
 
         # check unlikely case that ancestors have direct params which are offloaded
         offloaded_ancestors = offloaded & ancestors
-        if offloaded_ancestors:
-            names = set(module.__class__.__name__ for module in offloaded_ancestors)
+        for ancestor in offloaded_ancestors:
+            remove_hook_from_module(ancestor, recurse=False)
+            self.offloaded.remove(ancestor)
             logger.warning(
-                "The following modules are call graph ancestors of sequential targets,"
-                f"but also contain offloaded modules: {names}.\n"
-                "These modules will not be traced, and any sequential target children "
-                "will be executed jointly, which may lead to OOM errors"
+                f"Direct parameters attached to {ancestor.__class__.__name__} have "
+                "been onloaded in order to ensure safe graph capture and execution"
             )
 
     def create_arg(self, a: Any) -> Argument:

tests/llmcompressor/transformers/tracing/test_models.py

@@ -42,7 +42,14 @@
             "text",
             [],
         ),
-        ("RedHatAI/DeepSeek-V3-BF16", AutoModelForCausalLM, None, "text", []),
+        (
+            "ibm-granite/granite-20b-code-instruct-8k",
+            AutoModelForCausalLM,
+            None,
+            "text",
+            [],
+        ),
+        ("unsloth/DeepSeek-R1-0528-BF16", AutoModelForCausalLM, None, "text", []),
         # --- vision ---
         (
             "HuggingFaceM4/Idefics3-8B-Llama3",