Files
nvlabs--longlive/scripts/save_merged_nvfp4_generator.py
2026-07-13 12:31:40 +08:00

247 lines
9.7 KiB
Python

#!/usr/bin/env python3
# Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES
#
# Licensed under the Apache License, Version 2.0 (the "License").
# You may not use this file except in compliance with the License.
# To view a copy of this license, visit http://www.apache.org/licenses/LICENSE-2.0
#
# No warranties are given. The work is provided "AS IS", without warranty of any kind, express or implied.
#
# SPDX-License-Identifier: Apache-2.0
"""Save a merged LoRA generator as a reusable checkpoint."""
from __future__ import annotations
import argparse
import gc
import os
import sys
from pathlib import Path
import torch
from omegaconf import OmegaConf
PROJECT_ROOT = Path(__file__).resolve().parents[1]
if str(PROJECT_ROOT) not in sys.path:
sys.path.insert(0, str(PROJECT_ROOT))
from utils.config import normalize_config
from utils.lora_utils import configure_lora_for_model
from utils.nvfp4_checkpoint import (
NVFP4_CHECKPOINT_FORMAT,
NVFP4_CHECKPOINT_VERSION,
clean_fsdp_state_dict_keys,
cpu_state_dict,
is_nvfp4_state_dict,
quantize_model_for_fouroversix_nvfp4,
unwrap_generator_state_dict,
)
from utils.quant import _materialize_quantized_weights_for_inference
from utils.wan_5b_wrapper import WanDiffusionWrapper
def _torch_load(path: str):
try:
return torch.load(path, map_location="cpu", weights_only=False)
except TypeError:
return torch.load(path, map_location="cpu")
def _load_generator_checkpoint(generator: WanDiffusionWrapper, checkpoint_path: str, use_ema: bool) -> None:
checkpoint = _torch_load(checkpoint_path)
state_dict = unwrap_generator_state_dict(checkpoint, use_ema=use_ema)
if is_nvfp4_state_dict(state_dict):
raise ValueError(
f"{checkpoint_path} is already a materialized NVFP4 checkpoint; "
"use it directly as checkpoints.generator_ckpt."
)
if use_ema:
state_dict = clean_fsdp_state_dict_keys(state_dict)
incompatible = generator.load_state_dict(state_dict, strict=not use_ema)
missing = getattr(incompatible, "missing_keys", [])
unexpected = getattr(incompatible, "unexpected_keys", [])
if missing:
print(f"[Warning] Missing generator keys while loading base checkpoint: {missing[:8]} ...")
if unexpected:
print(f"[Warning] Unexpected generator keys while loading base checkpoint: {unexpected[:8]} ...")
def _load_lora_state(lora_ckpt_path: str):
checkpoint = _torch_load(lora_ckpt_path)
if isinstance(checkpoint, dict) and "generator_lora" in checkpoint:
return checkpoint["generator_lora"]
return checkpoint
def _merge_lora(generator: WanDiffusionWrapper, config, lora_ckpt_path: str) -> WanDiffusionWrapper:
if not getattr(config, "adapter", None):
raise ValueError("LoRA merge was requested, but config.adapter is missing.")
if not lora_ckpt_path:
raise ValueError("LoRA merge was requested, but no lora_ckpt was provided.")
print(f"Applying LoRA config: {config.adapter}")
generator.model = configure_lora_for_model(
generator.model,
model_name="generator",
lora_config=config.adapter,
is_main_process=True,
)
import peft
print(f"Loading LoRA weights: {lora_ckpt_path}")
peft.set_peft_model_state_dict(generator.model, _load_lora_state(lora_ckpt_path)) # type: ignore[arg-type]
print("Merging LoRA into generator...")
generator.model = generator.model.merge_and_unload(safe_merge=True)
return generator
def _metadata(
config,
args: argparse.Namespace,
*,
backend: str,
matched_modules: list[str],
materialized_modules: list[str],
):
checkpoint_format = (
"longlive_generator_merged_bf16"
if backend == "transformer_engine"
else NVFP4_CHECKPOINT_FORMAT
)
quant_format = "bf16" if backend == "transformer_engine" else "nvfp4"
quant_backend = "transformer_engine_runtime" if backend == "transformer_engine" else "fouroversix"
return {
"checkpoint_format": checkpoint_format,
"checkpoint_version": NVFP4_CHECKPOINT_VERSION,
"source_generator_ckpt": args.generator_ckpt,
"source_lora_ckpt": args.lora_ckpt,
"merged_lora": bool(args.lora_ckpt and not args.no_merge_lora),
"model_name": getattr(config.model_kwargs, "model_name", None),
"quantization": {
"format": quant_format,
"backend": quant_backend,
"materialized": backend == "fouroversix",
"dtype": "bfloat16",
"scale_rule": getattr(config, "model_quant_scale_rule", "static_6"),
"activation_scale_rule": getattr(config, "model_quant_activation_scale_rule", None),
"weight_scale_rule": getattr(config, "model_quant_weight_scale_rule", None),
"gradient_scale_rule": getattr(config, "model_quant_gradient_scale_rule", None),
"te_inference_only": bool(
getattr(config, "model_quant_te_inference_only", backend == "transformer_engine")
),
"te_low_precision_weights": bool(
getattr(config, "model_quant_te_low_precision_weights", backend == "transformer_engine")
),
"te_fallback_to_fouroversix": bool(
getattr(config, "model_quant_te_fallback_to_fouroversix", False)
),
"matched_filtered_modules": matched_modules,
"materialized_modules": materialized_modules,
},
}
def parse_args() -> argparse.Namespace:
parser = argparse.ArgumentParser(
description="Merge generator LoRA weights and save either packed FourOverSix NVFP4 or TE-ready bf16."
)
parser.add_argument("--config_path", required=True, help="Inference yaml that contains model/adapter/quant settings.")
parser.add_argument("--output_path", required=True, help="Path to save the generator .pt file.")
parser.add_argument("--generator_ckpt", default=None, help="Override checkpoints.generator_ckpt from the yaml.")
parser.add_argument("--lora_ckpt", default=None, help="Override checkpoints.lora_ckpt from the yaml.")
parser.add_argument("--device", default="cuda:0", help="Device used for quantization, e.g. cuda:0 or cpu.")
parser.add_argument(
"--backend",
choices=("fouroversix", "transformer_engine"),
default="fouroversix",
help=(
"fouroversix saves packed/materialized NVFP4. "
"transformer_engine saves merged bf16 for TE runtime quantization."
),
)
parser.add_argument("--no_merge_lora", action="store_true", help="Quantize the base generator without merging LoRA.")
return parser.parse_args()
def main() -> None:
args = parse_args()
config = normalize_config(OmegaConf.load(args.config_path))
args.generator_ckpt = args.generator_ckpt or getattr(config, "generator_ckpt", None)
args.lora_ckpt = args.lora_ckpt or getattr(config, "lora_ckpt", None)
if not args.generator_ckpt:
raise ValueError("Missing generator checkpoint. Set checkpoints.generator_ckpt or pass --generator_ckpt.")
config.model_quant_use_transformer_engine = args.backend == "transformer_engine"
device = torch.device(args.device)
print(f"Building generator on CPU: {config.model_kwargs}")
generator = WanDiffusionWrapper(**getattr(config, "model_kwargs", {}), is_causal=True)
generator.eval().requires_grad_(False)
print(f"Loading base generator checkpoint: {args.generator_ckpt}")
_load_generator_checkpoint(generator, args.generator_ckpt, use_ema=bool(getattr(config, "use_ema", False)))
should_merge_lora = bool(getattr(config, "merge_lora", False)) and not args.no_merge_lora
if should_merge_lora:
generator = _merge_lora(generator, config, args.lora_ckpt)
else:
print("Skipping LoRA merge; quantizing the loaded generator as-is.")
gc.collect()
if torch.cuda.is_available():
torch.cuda.empty_cache()
print(f"Moving generator to {device} and casting to bfloat16...")
generator.to(device=device, dtype=torch.bfloat16)
materialized_modules = []
if args.backend == "transformer_engine":
matched_modules = []
print(
"Saving merged bf16 weights for TransformerEngine runtime quantization. "
"TransformerEngine state_dict is not a packed NVFP4 storage format."
)
else:
generator.model, matched_modules = quantize_model_for_fouroversix_nvfp4(
generator.model,
config=config,
keep_master_weights=False,
verbose=True,
)
print("Materializing NVFP4 weights and dropping bf16 master weights...")
materialized_modules, master_bytes, quantized_bytes = _materialize_quantized_weights_for_inference(
generator.model,
target_device=device,
)
print(
"[NVFP4] "
f"materialized_modules={len(materialized_modules)}, "
f"master_weight={master_bytes / (1024 ** 3):.3f} GiB, "
f"quantized_weight={quantized_bytes / (1024 ** 3):.3f} GiB"
)
print("Copying checkpoint tensors to CPU for saving...")
if torch.cuda.is_available():
torch.cuda.empty_cache()
output_path = Path(args.output_path)
output_path.parent.mkdir(parents=True, exist_ok=True)
checkpoint = {
"generator": cpu_state_dict(generator),
**_metadata(
config,
args,
backend=args.backend,
matched_modules=matched_modules,
materialized_modules=materialized_modules,
),
}
torch.save(checkpoint, output_path)
size_gib = os.path.getsize(output_path) / (1024 ** 3)
print(f"Saved {args.backend} generator checkpoint to {output_path} ({size_gib:.3f} GiB)")
if __name__ == "__main__":
with torch.no_grad():
main()