Files
sglang/python/sglang/multimodal_gen/runtime/loader/component_loader.py

835 lines
31 KiB
Python

# Copied and adapted from: https://github.com/hao-ai-lab/FastVideo
# SPDX-License-Identifier: Apache-2.0
import dataclasses
import glob
import importlib.util
import json
import os
import traceback
from abc import ABC
from collections.abc import Generator, Iterable
from copy import deepcopy
from typing import Any, cast
import torch
import torch.distributed as dist
import torch.nn as nn
from diffusers import AutoModel
from safetensors.torch import load_file as safetensors_load_file
from torch.distributed import init_device_mesh
from transformers import AutoImageProcessor, AutoProcessor, AutoTokenizer
from transformers.utils import SAFE_WEIGHTS_INDEX_NAME
from sglang.multimodal_gen.configs.models import EncoderConfig, ModelConfig
from sglang.multimodal_gen.runtime.distributed import get_local_torch_device
from sglang.multimodal_gen.runtime.loader.fsdp_load import (
maybe_load_fsdp_model,
shard_model,
)
from sglang.multimodal_gen.runtime.loader.utils import set_default_torch_dtype
from sglang.multimodal_gen.runtime.loader.weight_utils import (
filter_duplicate_safetensors_files,
filter_files_not_needed_for_inference,
pt_weights_iterator,
safetensors_weights_iterator,
)
from sglang.multimodal_gen.runtime.models.registry import ModelRegistry
from sglang.multimodal_gen.runtime.platforms import current_platform
from sglang.multimodal_gen.runtime.server_args import ServerArgs
from sglang.multimodal_gen.runtime.utils.hf_diffusers_utils import (
get_config,
get_diffusers_component_config,
get_hf_config,
)
from sglang.multimodal_gen.runtime.utils.layerwise_offload import (
LayerwiseOffloadManager,
)
from sglang.multimodal_gen.runtime.utils.logging_utils import init_logger
from sglang.multimodal_gen.utils import PRECISION_TO_TYPE
logger = init_logger(__name__)
class skip_init_modules:
def __enter__(self):
# Save originals
self._orig_reset = {}
for cls in (nn.Linear, nn.Conv1d, nn.Conv2d, nn.Conv3d):
self._orig_reset[cls] = cls.reset_parameters
cls.reset_parameters = lambda self: None # skip init
def __exit__(self, exc_type, exc_value, traceback):
# restore originals
for cls, orig in self._orig_reset.items():
cls.reset_parameters = orig
def _normalize_module_type(module_type: str) -> str:
"""Normalize module types like 'text_encoder_2' -> 'text_encoder'."""
if module_type.endswith("_2"):
return module_type[:-2]
return module_type
def _clean_hf_config_inplace(model_config: dict) -> None:
"""Remove common extraneous HF fields if present."""
for key in (
"_name_or_path",
"transformers_version",
"model_type",
"tokenizer_class",
"torch_dtype",
):
model_config.pop(key, None)
def _list_safetensors_files(model_path: str) -> list[str]:
"""List all .safetensors files under a directory."""
return sorted(glob.glob(os.path.join(str(model_path), "*.safetensors")))
def get_memory_usage_of_component(module) -> float | None:
"""
returned value is in GB, rounded to 2 decimal digits
"""
if not isinstance(module, nn.Module):
return None
BYTES_PER_GB = 1024**3
if hasattr(module, "get_memory_footprint"):
usage = module.get_memory_footprint() / BYTES_PER_GB
else:
# manually
param_size = sum(p.numel() * p.element_size() for p in module.parameters())
buffer_size = sum(b.numel() * b.element_size() for b in module.buffers())
total_size_bytes = param_size + buffer_size
usage = total_size_bytes / (1024**3)
return round(usage, 2)
class ComponentLoader(ABC):
"""Base class for loading a specific type of model component."""
def __init__(self, device=None) -> None:
self.device = device
def should_offload(
self, server_args: ServerArgs, model_config: ModelConfig | None = None
):
# not offload by default
return False
def target_device(self, should_offload):
if should_offload:
return (
torch.device("mps")
if current_platform.is_mps()
else torch.device("cpu")
)
else:
return get_local_torch_device()
def load(
self,
component_model_path: str,
server_args: ServerArgs,
module_name: str,
transformers_or_diffusers: str,
) -> tuple[AutoModel, float]:
"""
Template method that standardizes logging around the core load implementation.
The priority of loading method is:
1. load customized module
2. load native diffusers/transformers module
If all of the above methods failed, an error will be thrown
"""
gpu_mem_before_loading = current_platform.get_available_gpu_memory()
logger.info(
"Loading %s from %s. avail mem: %.2f GB",
module_name,
component_model_path,
gpu_mem_before_loading,
)
try:
component = self.load_customized(
component_model_path, server_args, module_name
)
source = "customized"
except Exception as e:
if "Unsupported model architecture" in str(e):
logger.info(
f"Module: {module_name} doesn't have a customized version yet, using native version"
)
else:
traceback.print_exc()
logger.error(
f"Error while loading customized {module_name}, falling back to native version"
)
# fallback to native version
component = self.load_native(
component_model_path, server_args, transformers_or_diffusers
)
should_offload = self.should_offload(server_args)
target_device = self.target_device(should_offload)
component = component.to(device=target_device)
source = "native"
logger.warning(
"Native module %s: %s is loaded, performance may be sub-optimal",
module_name,
component.__class__.__name__,
)
if component is None:
logger.warning("Loaded %s returned None", module_name)
consumed = 0.0
else:
current_gpu_mem = current_platform.get_available_gpu_memory()
consumed = get_memory_usage_of_component(component)
if consumed is None or consumed == 0.0:
consumed = gpu_mem_before_loading - current_gpu_mem
logger.info(
f"Loaded %s: %s from {source}. model size: %.2f GB, avail mem: %.2f GB",
module_name,
component.__class__.__name__,
consumed,
current_gpu_mem,
)
return component, consumed
def load_native(
self,
component_model_path: str,
server_args: ServerArgs,
transformers_or_diffusers: str,
) -> AutoModel:
"""
Load the component using the native library (transformers/diffusers).
"""
if transformers_or_diffusers == "transformers":
from transformers import AutoModel
config = get_hf_config(
component_model_path,
trust_remote_code=server_args.trust_remote_code,
revision=server_args.revision,
)
return AutoModel.from_pretrained(
component_model_path,
config=config,
trust_remote_code=server_args.trust_remote_code,
revision=server_args.revision,
)
elif transformers_or_diffusers == "diffusers":
from diffusers import AutoModel
return AutoModel.from_pretrained(
component_model_path,
revision=server_args.revision,
trust_remote_code=server_args.trust_remote_code,
)
else:
raise ValueError(f"Unsupported library: {transformers_or_diffusers}")
def load_customized(
self, component_model_path: str, server_args: ServerArgs, module_name: str
):
"""
Load the customized version component, implemented and optimized in SGL-diffusion
"""
raise NotImplementedError(
f"load_customized not implemented for {self.__class__.__name__}"
)
@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_type = _normalize_module_type(module_type)
module_loaders = {
"scheduler": (SchedulerLoader, "diffusers"),
"transformer": (TransformerLoader, "diffusers"),
"vae": (VAELoader, "diffusers"),
"text_encoder": (TextEncoderLoader, "transformers"),
"tokenizer": (TokenizerLoader, "transformers"),
"image_processor": (ImageProcessorLoader, "transformers"),
"image_encoder": (ImageEncoderLoader, "transformers"),
"processor": (AutoProcessorLoader, "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."""
def should_offload(self, server_args, model_config: ModelConfig | None = None):
should_offload = server_args.text_encoder_cpu_offload
if not should_offload:
return False
# _fsdp_shard_conditions is in arch_config, not directly on model_config
arch_config = (
getattr(model_config, "arch_config", model_config) if model_config else None
)
fsdp_shard_conditions = (
getattr(arch_config, "_fsdp_shard_conditions", []) if arch_config else []
)
use_cpu_offload = should_offload and len(fsdp_shard_conditions) > 0
return use_cpu_offload
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)
# 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_customized(
self, component_model_path: str, server_args: ServerArgs, module_name: str
):
"""Load the text encoders based on the model path, and inference args."""
# model_config: PretrainedConfig = get_hf_config(
# model=model_path,
# trust_remote_code=server_args.trust_remote_code,
# revision=server_args.revision,
# model_override_args=None,
# )
diffusers_pretrained_config = get_config(
component_model_path, trust_remote_code=True
)
model_config = get_diffusers_component_config(model_path=component_model_path)
_clean_hf_config_inplace(model_config)
logger.info("HF model config: %s", model_config)
def is_not_first_encoder(module_name):
return "2" in module_name
# TODO(mick): had to throw an exception for different text-encoder arch
if not is_not_first_encoder(module_name):
encoder_config = server_args.pipeline_config.text_encoder_configs[0]
encoder_config.update_model_arch(model_config)
for key, value in diffusers_pretrained_config.__dict__.items():
setattr(encoder_config.arch_config, key, value)
encoder_dtype = server_args.pipeline_config.text_encoder_precisions[0]
else:
assert len(server_args.pipeline_config.text_encoder_configs) == 2
encoder_config = server_args.pipeline_config.text_encoder_configs[1]
encoder_config.update_model_arch(model_config)
encoder_dtype = server_args.pipeline_config.text_encoder_precisions[1]
# TODO(will): add support for other dtypes
return self.load_model(
component_model_path,
encoder_config,
server_args,
encoder_dtype,
)
def load_model(
self,
model_path: str,
model_config: EncoderConfig,
server_args: ServerArgs,
dtype: str = "fp16",
cpu_offload_flag: bool | None = None,
):
# Determine CPU offload behavior and target device
local_torch_device = get_local_torch_device()
should_offload = self.should_offload(server_args, model_config)
with set_default_torch_dtype(PRECISION_TO_TYPE[dtype]):
with local_torch_device, skip_init_modules():
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=should_offload)
)
# Explicitly move model to target device after loading weights
model = model.to(local_torch_device)
if should_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"
)
else:
mesh = init_device_mesh(
current_platform.device_type,
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_config.arch_config._fsdp_shard_conditions
or getattr(model, "_fsdp_shard_conditions", None),
pin_cpu_memory=server_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 model weights were not initialized from "
f"checkpoint: {weights_not_loaded}"
)
return model.eval()
class ImageEncoderLoader(TextEncoderLoader):
def should_offload(self, server_args, model_config: ModelConfig | None = None):
should_offload = server_args.image_encoder_cpu_offload
if not should_offload:
return False
# _fsdp_shard_conditions is in arch_config, not directly on model_config
arch_config = (
getattr(model_config, "arch_config", model_config) if model_config else None
)
fsdp_shard_conditions = (
getattr(arch_config, "_fsdp_shard_conditions", []) if arch_config else []
)
use_cpu_offload = should_offload and len(fsdp_shard_conditions) > 0
return use_cpu_offload
def load_customized(
self, component_model_path: str, server_args: ServerArgs, *args
):
"""Load the text encoders based on the model path, and inference args."""
# model_config: PretrainedConfig = get_hf_config(
# model=model_path,
# trust_remote_code=server_args.trust_remote_code,
# revision=server_args.revision,
# model_override_args=None,
# )
with open(os.path.join(component_model_path, "config.json")) as f:
model_config = json.load(f)
_clean_hf_config_inplace(model_config)
logger.info("HF model config: %s", model_config)
encoder_config = server_args.pipeline_config.image_encoder_config
encoder_config.update_model_arch(model_config)
# Always start with local device; load_model will adjust for offload if needed
# TODO(will): add support for other dtypes
return self.load_model(
component_model_path,
encoder_config,
server_args,
server_args.pipeline_config.image_encoder_precision,
cpu_offload_flag=server_args.image_encoder_cpu_offload,
)
class ImageProcessorLoader(ComponentLoader):
"""Loader for image processor."""
def load_customized(
self, component_model_path: str, server_args: ServerArgs, module_name: str
) -> Any:
return AutoImageProcessor.from_pretrained(component_model_path, use_fast=True)
class AutoProcessorLoader(ComponentLoader):
"""Loader for auto processor."""
def load_customized(
self, component_model_path: str, server_args: ServerArgs, module_name: str
) -> Any:
return AutoProcessor.from_pretrained(component_model_path)
class TokenizerLoader(ComponentLoader):
"""Loader for tokenizers."""
def load_customized(
self, component_model_path: str, server_args: ServerArgs, module_name: str
) -> Any:
return AutoTokenizer.from_pretrained(
component_model_path,
padding_size="right",
)
class VAELoader(ComponentLoader):
"""Loader for VAE."""
def should_offload(
self, server_args: ServerArgs, model_config: ModelConfig | None = None
):
return server_args.vae_cpu_offload
def load_customized(
self, component_model_path: str, server_args: ServerArgs, *args
):
"""Load the VAE based on the model path, and inference args."""
config = get_diffusers_component_config(model_path=component_model_path)
class_name = config.pop("_class_name", None)
assert (
class_name is not None
), "Model config does not contain a _class_name attribute. Only diffusers format is supported."
server_args.model_paths["vae"] = component_model_path
logger.info("HF model config: %s", config)
vae_config = server_args.pipeline_config.vae_config
vae_config.update_model_arch(config)
# NOTE: some post init logics are only available after updated with config
vae_config.post_init()
should_offload = self.should_offload(server_args)
target_device = self.target_device(should_offload)
# Check for auto_map first (custom VAE classes)
auto_map = config.get("auto_map", {})
auto_model_map = auto_map.get("AutoModel")
if auto_model_map:
module_path, cls_name = auto_model_map.rsplit(".", 1)
custom_module_file = os.path.join(component_model_path, f"{module_path}.py")
spec = importlib.util.spec_from_file_location("_custom", custom_module_file)
custom_module = importlib.util.module_from_spec(spec)
spec.loader.exec_module(custom_module)
vae_cls = getattr(custom_module, cls_name)
vae_dtype = PRECISION_TO_TYPE[server_args.pipeline_config.vae_precision]
with set_default_torch_dtype(vae_dtype):
vae = vae_cls.from_pretrained(
component_model_path,
revision=server_args.revision,
trust_remote_code=server_args.trust_remote_code,
)
vae = vae.to(device=target_device, dtype=vae_dtype)
return vae.eval()
# Load from ModelRegistry (standard VAE classes)
with (
set_default_torch_dtype(
PRECISION_TO_TYPE[server_args.pipeline_config.vae_precision]
),
skip_init_modules(),
):
vae_cls, _ = ModelRegistry.resolve_model_cls(class_name)
vae = vae_cls(vae_config).to(target_device)
safetensors_list = _list_safetensors_files(component_model_path)
assert (
len(safetensors_list) == 1
), f"Found {len(safetensors_list)} safetensors files in {component_model_path}"
loaded = safetensors_load_file(safetensors_list[0])
vae.load_state_dict(loaded, strict=False)
return vae.eval()
class TransformerLoader(ComponentLoader):
"""Loader for transformer."""
def load_customized(
self, component_model_path: str, server_args: ServerArgs, *args
):
"""Load the transformer based on the model path, and inference args."""
config = get_diffusers_component_config(model_path=component_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."
)
server_args.model_paths["transformer"] = component_model_path
# Config from Diffusers supersedes sgl_diffusion's model config
dit_config = server_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 = _list_safetensors_files(component_model_path)
if not safetensors_list:
raise ValueError(f"No safetensors files found in {component_model_path}")
# Check if we should use custom initialization weights
custom_weights_path = getattr(
server_args, "init_weights_from_safetensors", None
)
use_custom_weights = False
if use_custom_weights:
logger.info(
"Using custom initialization weights from: %s", custom_weights_path
)
assert (
custom_weights_path is not None
), "Custom initialization weights must be provided"
if os.path.isdir(custom_weights_path):
safetensors_list = _list_safetensors_files(custom_weights_path)
else:
assert custom_weights_path.endswith(
".safetensors"
), "Custom initialization weights must be a safetensors file"
safetensors_list = [custom_weights_path]
default_dtype = PRECISION_TO_TYPE[server_args.pipeline_config.dit_precision]
logger.info(
"Loading %s from %s safetensors files, default_dtype: %s",
cls_name,
len(safetensors_list),
default_dtype,
)
# Load the model using FSDP loader
assert server_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=server_args.hsdp_replicate_dim,
hsdp_shard_dim=server_args.hsdp_shard_dim,
cpu_offload=server_args.dit_cpu_offload,
pin_cpu_memory=server_args.pin_cpu_memory,
fsdp_inference=server_args.use_fsdp_inference,
# TODO(will): make these configurable
default_dtype=default_dtype,
param_dtype=torch.bfloat16,
reduce_dtype=torch.float32,
output_dtype=None,
)
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()
if server_args.dit_layerwise_offload and hasattr(model, "dit_module_names"):
# TODO(will): support multiple module names
module_name = getattr(model, "dit_module_names", ["transformer_blocks"])[0]
try:
num_layers = len(getattr(model, module_name))
except Exception:
num_layers = None
if isinstance(num_layers, int) and num_layers > 0:
mgr = LayerwiseOffloadManager(
model,
module_list_attr=module_name,
num_layers=num_layers,
enabled=True,
pin_cpu_memory=server_args.pin_cpu_memory,
auto_initialize=True,
)
setattr(model, "_layerwise_offload_manager", mgr)
return model
class SchedulerLoader(ComponentLoader):
"""Loader for scheduler."""
def load_customized(
self, component_model_path: str, server_args: ServerArgs, *args
):
"""Load the scheduler based on the model path, and inference args."""
config = get_diffusers_component_config(model_path=component_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 server_args.pipeline_config.flow_shift is not None:
scheduler.set_shift(server_args.pipeline_config.flow_shift)
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
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,
server_args: ServerArgs,
):
"""
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
Returns:
The loaded module
"""
# Get the appropriate loader for this module type
loader = ComponentLoader.for_module_type(module_name, transformers_or_diffusers)
try:
# Load the module
return loader.load(
component_model_path,
server_args,
module_name,
transformers_or_diffusers,
)
except Exception as e:
logger.error(
f"Error while loading component: {module_name}, {component_model_path=}"
)
raise e