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hao-ai-lab-FastVideo/fastvideo/models/loader/component_loader.py
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# SPDX-License-Identifier: Apache-2.0
import dataclasses
import glob
import json
import os
import time
from abc import ABC, abstractmethod
from collections.abc import Generator, Iterable
from copy import deepcopy
from typing import cast
import torch
import torch.distributed as dist
import torch.nn as nn
from safetensors.torch import load_file as safetensors_load_file
from torch.distributed import init_device_mesh
from transformers import AutoImageProcessor, AutoTokenizer
from transformers import UMT5EncoderModel
from transformers.utils import SAFE_WEIGHTS_INDEX_NAME
from fastvideo.configs.models import EncoderConfig
from fastvideo.distributed import get_local_torch_device
from fastvideo.fastvideo_args import FastVideoArgs
from fastvideo.logger import init_logger
from fastvideo.models.hf_transformer_utils import get_diffusers_config
from fastvideo.models.loader.fsdp_load import maybe_load_fsdp_model, shard_model
from fastvideo.models.loader.utils import set_default_torch_dtype
from fastvideo.models.loader.weight_utils import (
filter_duplicate_safetensors_files, filter_files_not_needed_for_inference,
pt_weights_iterator, safetensors_weights_iterator)
from fastvideo.models.registry import ModelRegistry
from fastvideo.utils import PRECISION_TO_TYPE
logger = init_logger(__name__)
class ComponentLoader(ABC):
"""Base class for loading a specific type of model component."""
def __init__(self, device=None) -> None:
self.device = device
@abstractmethod
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""
Load the component based on the model path, architecture, and inference args.
Args:
model_path: Path to the component model
fastvideo_args: FastVideoArgs
Returns:
The loaded component
"""
raise NotImplementedError
@classmethod
def for_module_type(cls, module_type: str,
transformers_or_diffusers: str) -> 'ComponentLoader':
"""
Factory method to create a component loader for a specific module type.
Args:
module_type: Type of module (e.g., "vae", "text_encoder", "transformer", "scheduler")
transformers_or_diffusers: Whether the module is from transformers or diffusers
Returns:
A component loader for the specified module type
"""
# Map of module types to their loader classes and expected library
module_loaders = {
"scheduler": (SchedulerLoader, "diffusers"),
"transformer": (TransformerLoader, "diffusers"),
"transformer_2": (TransformerLoader, "diffusers"),
"vae": (VAELoader, "diffusers"),
"text_encoder": (TextEncoderLoader, "transformers"),
"text_encoder_2": (TextEncoderLoader, "transformers"),
"tokenizer": (TokenizerLoader, "transformers"),
"tokenizer_2": (TokenizerLoader, "transformers"),
"image_processor": (ImageProcessorLoader, "transformers"),
"image_encoder": (ImageEncoderLoader, "transformers"),
}
if module_type in module_loaders:
loader_cls, expected_library = module_loaders[module_type]
# Assert that the library matches what's expected for this module type
assert transformers_or_diffusers == expected_library, f"{module_type} must be loaded from {expected_library}, got {transformers_or_diffusers}"
return loader_cls()
# For unknown module types, use a generic loader
logger.warning(
"No specific loader found for module type: %s. Using generic loader.",
module_type)
return GenericComponentLoader(transformers_or_diffusers)
class TextEncoderLoader(ComponentLoader):
"""Loader for text encoders."""
@dataclasses.dataclass
class Source:
"""A source for weights."""
model_or_path: str
"""The model ID or path."""
prefix: str = ""
"""A prefix to prepend to all weights."""
fall_back_to_pt: bool = True
"""Whether .pt weights can be used."""
allow_patterns_overrides: list[str] | None = None
"""If defined, weights will load exclusively using these patterns."""
counter_before_loading_weights: float = 0.0
counter_after_loading_weights: float = 0.0
def _prepare_weights(
self,
model_name_or_path: str,
fall_back_to_pt: bool,
allow_patterns_overrides: list[str] | None,
) -> tuple[str, list[str], bool]:
"""Prepare weights for the model.
If the model is not local, it will be downloaded."""
# model_name_or_path = (self._maybe_download_from_modelscope(
# model_name_or_path, revision) or model_name_or_path)
is_local = os.path.isdir(model_name_or_path)
assert is_local, "Model path must be a local directory"
use_safetensors = False
index_file = SAFE_WEIGHTS_INDEX_NAME
allow_patterns = ["*.safetensors", "*.bin"]
if fall_back_to_pt:
allow_patterns += ["*.pt"]
if allow_patterns_overrides is not None:
allow_patterns = allow_patterns_overrides
hf_folder = model_name_or_path
hf_weights_files: list[str] = []
for pattern in allow_patterns:
hf_weights_files += glob.glob(os.path.join(hf_folder, pattern))
if len(hf_weights_files) > 0:
if pattern == "*.safetensors":
use_safetensors = True
break
if use_safetensors:
hf_weights_files = filter_duplicate_safetensors_files(
hf_weights_files, hf_folder, index_file)
else:
hf_weights_files = filter_files_not_needed_for_inference(
hf_weights_files)
if len(hf_weights_files) == 0:
raise RuntimeError(
f"Cannot find any model weights with `{model_name_or_path}`")
return hf_folder, hf_weights_files, use_safetensors
def _get_weights_iterator(
self, source: "Source",
to_cpu: bool) -> Generator[tuple[str, torch.Tensor], None, None]:
"""Get an iterator for the model weights based on the load format."""
hf_folder, hf_weights_files, use_safetensors = self._prepare_weights(
source.model_or_path, source.fall_back_to_pt,
source.allow_patterns_overrides)
if use_safetensors:
weights_iterator = safetensors_weights_iterator(hf_weights_files,
to_cpu=to_cpu)
else:
weights_iterator = pt_weights_iterator(hf_weights_files,
to_cpu=to_cpu)
if self.counter_before_loading_weights == 0.0:
self.counter_before_loading_weights = time.perf_counter()
# Apply the prefix.
return ((source.prefix + name, tensor)
for (name, tensor) in weights_iterator)
def _get_all_weights(
self,
model: nn.Module,
model_path: str,
to_cpu: bool,
) -> Generator[tuple[str, torch.Tensor], None, None]:
primary_weights = TextEncoderLoader.Source(
model_path,
prefix="",
fall_back_to_pt=getattr(model, "fall_back_to_pt_during_load", True),
allow_patterns_overrides=getattr(model, "allow_patterns_overrides",
None),
)
yield from self._get_weights_iterator(primary_weights, to_cpu)
secondary_weights = cast(
Iterable[TextEncoderLoader.Source],
getattr(model, "secondary_weights", ()),
)
for source in secondary_weights:
yield from self._get_weights_iterator(source, to_cpu)
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load the text encoders based on the model path, and inference args."""
# model_config: PretrainedConfig = get_hf_config(
# model=model_path,
# trust_remote_code=fastvideo_args.trust_remote_code,
# revision=fastvideo_args.revision,
# model_override_args=None,
# )
model_config = get_diffusers_config(model=model_path)
model_config.pop("_name_or_path", None)
model_config.pop("transformers_version", None)
model_config.pop("model_type", None)
model_config.pop("tokenizer_class", None)
model_config.pop("torch_dtype", None)
logger.info("HF Model config: %s", model_config)
# @TODO(Wei): Better way to handle this?
try:
encoder_config = fastvideo_args.pipeline_config.text_encoder_configs[
0]
encoder_config.update_model_arch(model_config)
encoder_precision = fastvideo_args.pipeline_config.text_encoder_precisions[
0]
except Exception:
encoder_config = fastvideo_args.pipeline_config.text_encoder_configs[
1]
encoder_config.update_model_arch(model_config)
encoder_precision = fastvideo_args.pipeline_config.text_encoder_precisions[
1]
target_device = get_local_torch_device()
# TODO(will): add support for other dtypes
return self.load_model(model_path, encoder_config, target_device,
fastvideo_args, encoder_precision)
def load_model(self,
model_path: str,
model_config: EncoderConfig,
target_device: torch.device,
fastvideo_args: FastVideoArgs,
dtype: str = "fp16"):
use_cpu_offload = fastvideo_args.text_encoder_cpu_offload and len(
getattr(model_config, "_fsdp_shard_conditions", [])) > 0
from fastvideo.platforms import current_platform
if fastvideo_args.text_encoder_cpu_offload:
target_device = torch.device(
"mps") if current_platform.is_mps() else torch.device("cpu")
with set_default_torch_dtype(PRECISION_TO_TYPE[dtype]):
with target_device:
architectures = getattr(model_config, "architectures", [])
model_cls, _ = ModelRegistry.resolve_model_cls(architectures)
model = model_cls(model_config)
weights_to_load = {name for name, _ in model.named_parameters()}
loaded_weights = model.load_weights(
self._get_all_weights(model, model_path,
to_cpu=use_cpu_offload))
self.counter_after_loading_weights = time.perf_counter()
logger.info(
"Loading weights took %.2f seconds",
self.counter_after_loading_weights -
self.counter_before_loading_weights)
# Explicitly move model to target device after loading weights
model = model.to(target_device)
from fastvideo.platforms import current_platform
if use_cpu_offload:
# Disable FSDP for MPS as it's not compatible
if current_platform.is_mps():
logger.info(
"Disabling FSDP sharding for MPS platform as it's not compatible"
)
elif current_platform.is_npu():
mesh = init_device_mesh(
"npu",
mesh_shape=(1, dist.get_world_size()),
mesh_dim_names=("offload", "replicate"),
)
shard_model(
model,
cpu_offload=True,
reshard_after_forward=True,
mesh=mesh["offload"],
fsdp_shard_conditions=model._fsdp_shard_conditions,
pin_cpu_memory=fastvideo_args.pin_cpu_memory)
else:
mesh = init_device_mesh(
"cuda",
mesh_shape=(1, dist.get_world_size()),
mesh_dim_names=("offload", "replicate"),
)
shard_model(
model,
cpu_offload=True,
reshard_after_forward=True,
mesh=mesh["offload"],
fsdp_shard_conditions=model._fsdp_shard_conditions,
pin_cpu_memory=fastvideo_args.pin_cpu_memory)
# We only enable strict check for non-quantized models
# that have loaded weights tracking currently.
# if loaded_weights is not None:
weights_not_loaded = weights_to_load - loaded_weights
if weights_not_loaded:
raise ValueError("Following weights were not initialized from "
f"checkpoint: {weights_not_loaded}")
return model.eval()
class ImageEncoderLoader(TextEncoderLoader):
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load the text encoders based on the model path, and inference args."""
# model_config: PretrainedConfig = get_hf_config(
# model=model_path,
# trust_remote_code=fastvideo_args.trust_remote_code,
# revision=fastvideo_args.revision,
# model_override_args=None,
# )
with open(os.path.join(model_path, "config.json")) as f:
model_config = json.load(f)
model_config.pop("_name_or_path", None)
model_config.pop("transformers_version", None)
model_config.pop("torch_dtype", None)
model_config.pop("model_type", None)
logger.info("HF Model config: %s", model_config)
encoder_config = fastvideo_args.pipeline_config.image_encoder_config
encoder_config.update_model_arch(model_config)
from fastvideo.platforms import current_platform
if fastvideo_args.image_encoder_cpu_offload:
target_device = torch.device("mps") if current_platform.is_mps() else torch.device("cpu")
else:
target_device = get_local_torch_device()
# TODO(will): add support for other dtypes
return self.load_model(
model_path, encoder_config, target_device, fastvideo_args,
fastvideo_args.pipeline_config.image_encoder_precision)
class ImageProcessorLoader(ComponentLoader):
"""Loader for image processor."""
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load the image processor based on the model path, and inference args."""
logger.info("Loading image processor from %s", model_path)
image_processor = AutoImageProcessor.from_pretrained(model_path, )
logger.info("Loaded image processor: %s",
image_processor.__class__.__name__)
return image_processor
class TokenizerLoader(ComponentLoader):
"""Loader for tokenizers."""
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load the tokenizer based on the model path, and inference args."""
logger.info("Loading tokenizer from %s", model_path)
tokenizer = AutoTokenizer.from_pretrained(
model_path, # "<path to model>/tokenizer"
# in v0, this was same string as encoder_name "ClipTextModel"
# TODO(will): pass these tokenizer kwargs from inference args? Maybe
# other method of config?
padding_size='right',
)
logger.info("Loaded tokenizer: %s", tokenizer.__class__.__name__)
return tokenizer
class VAELoader(ComponentLoader):
"""Loader for VAE."""
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load the VAE based on the model path, and inference args."""
config = get_diffusers_config(model=model_path)
class_name = config.pop("_class_name")
assert class_name is not None, "Model config does not contain a _class_name attribute. Only diffusers format is supported."
fastvideo_args.model_paths["vae"] = model_path
vae_config = fastvideo_args.pipeline_config.vae_config
vae_config.update_model_arch(config)
from fastvideo.platforms import current_platform
if fastvideo_args.vae_cpu_offload:
target_device = torch.device("mps") if current_platform.is_mps() else torch.device("cpu")
else:
target_device = get_local_torch_device()
with set_default_torch_dtype(PRECISION_TO_TYPE[
fastvideo_args.pipeline_config.vae_precision] if fastvideo_args.pipeline_config.vae_precision else torch.bfloat16):
vae_cls, _ = ModelRegistry.resolve_model_cls(class_name)
vae = vae_cls(vae_config).to(target_device)
# Find all safetensors files
safetensors_list = glob.glob(
os.path.join(str(model_path), "*.safetensors"))
loaded = {}
for sf_file in safetensors_list:
loaded.update(safetensors_load_file(sf_file))
vae.load_state_dict(
loaded, strict=False) # We might only load encoder or decoder
return vae.eval()
class TransformerLoader(ComponentLoader):
"""Loader for transformer."""
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load the transformer based on the model path, and inference args."""
config = get_diffusers_config(model=model_path)
hf_config = deepcopy(config)
cls_name = config.pop("_class_name")
if cls_name is None:
raise ValueError(
"Model config does not contain a _class_name attribute. "
"Only diffusers format is supported.")
logger.info("transformer cls_name: %s", cls_name)
if fastvideo_args.override_transformer_cls_name is not None:
cls_name = fastvideo_args.override_transformer_cls_name
logger.info("Overriding transformer cls_name to %s", cls_name)
fastvideo_args.model_paths["transformer"] = model_path
# Config from Diffusers supersedes fastvideo's model config
dit_config = fastvideo_args.pipeline_config.dit_config
dit_config.update_model_arch(config)
model_cls, _ = ModelRegistry.resolve_model_cls(cls_name)
# Find all safetensors files
safetensors_list = glob.glob(
os.path.join(str(model_path), "*.safetensors"))
if not safetensors_list:
raise ValueError(f"No safetensors files found in {model_path}")
# Check if we should use custom initialization weights
custom_weights_path = getattr(fastvideo_args, 'init_weights_from_safetensors', None)
use_custom_weights = (custom_weights_path and os.path.exists(custom_weights_path) and
not hasattr(fastvideo_args, '_loading_teacher_critic_model'))
if use_custom_weights:
if 'transformer_2' in model_path:
custom_weights_path = getattr(fastvideo_args, 'init_weights_from_safetensors_2', None)
assert custom_weights_path is not None, "Custom initialization weights must be provided"
if os.path.isdir(custom_weights_path):
safetensors_list = glob.glob(
os.path.join(str(custom_weights_path), "*.safetensors"))
else:
assert custom_weights_path.endswith(".safetensors"), "Custom initialization weights must be a safetensors file"
safetensors_list = [custom_weights_path]
logger.info("Loading model from %s safetensors files: %s",
len(safetensors_list), safetensors_list)
default_dtype = PRECISION_TO_TYPE[
fastvideo_args.pipeline_config.dit_precision]
# Load the model using FSDP loader
assert fastvideo_args.hsdp_shard_dim is not None
model = maybe_load_fsdp_model(
model_cls=model_cls,
init_params={
"config": dit_config,
"hf_config": hf_config
},
weight_dir_list=safetensors_list,
device=get_local_torch_device(),
hsdp_replicate_dim=fastvideo_args.hsdp_replicate_dim,
hsdp_shard_dim=fastvideo_args.hsdp_shard_dim,
cpu_offload=fastvideo_args.dit_cpu_offload,
pin_cpu_memory=fastvideo_args.pin_cpu_memory,
fsdp_inference=fastvideo_args.use_fsdp_inference,
# TODO(will): make these configurable
default_dtype=default_dtype,
param_dtype=torch.bfloat16,
reduce_dtype=torch.float32,
output_dtype=None,
training_mode=fastvideo_args.training_mode,
enable_torch_compile=fastvideo_args.enable_torch_compile,
torch_compile_kwargs=fastvideo_args.torch_compile_kwargs)
total_params = sum(p.numel() for p in model.parameters())
logger.info("Loaded model with %.2fB parameters", total_params / 1e9)
assert next(model.parameters()).dtype == default_dtype, "Model dtype does not match default dtype"
model = model.eval()
return model
class SchedulerLoader(ComponentLoader):
"""Loader for scheduler."""
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load the scheduler based on the model path, and inference args."""
config = get_diffusers_config(model=model_path)
class_name = config.pop("_class_name")
assert class_name is not None, "Model config does not contain a _class_name attribute. Only diffusers format is supported."
scheduler_cls, _ = ModelRegistry.resolve_model_cls(class_name)
scheduler = scheduler_cls(**config)
if fastvideo_args.pipeline_config.flow_shift is not None:
scheduler.set_shift(fastvideo_args.pipeline_config.flow_shift)
if fastvideo_args.pipeline_config.timesteps_scale is not None:
scheduler.set_timesteps_scale(
fastvideo_args.pipeline_config.timesteps_scale)
return scheduler
class GenericComponentLoader(ComponentLoader):
"""Generic loader for components that don't have a specific loader."""
def __init__(self, library="transformers") -> None:
super().__init__()
self.library = library
def load(self, model_path: str, fastvideo_args: FastVideoArgs):
"""Load a generic component based on the model path, and inference args."""
logger.warning("Using generic loader for %s with library %s",
model_path, self.library)
if self.library == "transformers":
from transformers import AutoModel
model = AutoModel.from_pretrained(
model_path,
trust_remote_code=fastvideo_args.trust_remote_code,
revision=fastvideo_args.revision,
)
logger.info("Loaded generic transformers model: %s",
model.__class__.__name__)
return model
elif self.library == "diffusers":
logger.warning(
"Generic loading for diffusers components is not fully implemented"
)
model_config = get_diffusers_config(model=model_path)
logger.info("Diffusers Model config: %s", model_config)
# This is a placeholder - in a real implementation, you'd need to handle this properly
return None
else:
raise ValueError(f"Unsupported library: {self.library}")
class PipelineComponentLoader:
"""
Utility class for loading pipeline components.
This replaces the chain of if-else statements in load_pipeline_module.
"""
@staticmethod
def load_module(module_name: str, component_model_path: str,
transformers_or_diffusers: str,
fastvideo_args: FastVideoArgs):
"""
Load a pipeline module.
Args:
module_name: Name of the module (e.g., "vae", "text_encoder", "transformer", "scheduler")
component_model_path: Path to the component model
transformers_or_diffusers: Whether the module is from transformers or diffusers
pipeline_args: Inference arguments
Returns:
The loaded module
"""
logger.info(
"Loading %s using %s from %s",
module_name,
transformers_or_diffusers,
component_model_path,
)
# Get the appropriate loader for this module type
loader = ComponentLoader.for_module_type(module_name,
transformers_or_diffusers)
# Load the module
return loader.load(component_model_path, fastvideo_args)