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vllm/vllm/model_executor/model_loader.py
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"""Utilities for selecting and loading models."""
import contextlib
from typing import Type
import torch
import torch.nn as nn
from transformers import PretrainedConfig
from vllm.config import ModelConfig
from vllm.model_executor.models import * # pylint: disable=wildcard-import
from vllm.model_executor.weight_utils import initialize_dummy_weights
# TODO(woosuk): Lazy-load the model classes.
_MODEL_REGISTRY = {
"AquilaModel": AquilaForCausalLM,
"BaiChuanForCausalLM": BaiChuanForCausalLM, # baichuan-7b
"BaichuanForCausalLM": BaichuanForCausalLM, # baichuan-13b
"BloomForCausalLM": BloomForCausalLM,
"FalconForCausalLM": FalconForCausalLM,
"GPT2LMHeadModel": GPT2LMHeadModel,
"GPTBigCodeForCausalLM": GPTBigCodeForCausalLM,
"GPTJForCausalLM": GPTJForCausalLM,
"GPTNeoXForCausalLM": GPTNeoXForCausalLM,
"InternLMForCausalLM": InternLMForCausalLM,
"LlamaForCausalLM": LlamaForCausalLM,
"LLaMAForCausalLM": LlamaForCausalLM, # For decapoda-research/llama-*
"MPTForCausalLM": MPTForCausalLM,
"OPTForCausalLM": OPTForCausalLM,
"QWenLMHeadModel": QWenLMHeadModel,
"RWForCausalLM": FalconForCausalLM,
}
@contextlib.contextmanager
def _set_default_torch_dtype(dtype: torch.dtype):
"""Sets the default torch dtype to the given dtype."""
old_dtype = torch.get_default_dtype()
torch.set_default_dtype(dtype)
yield
torch.set_default_dtype(old_dtype)
def _get_model_architecture(config: PretrainedConfig) -> Type[nn.Module]:
architectures = getattr(config, "architectures", [])
for arch in architectures:
if arch in _MODEL_REGISTRY:
return _MODEL_REGISTRY[arch]
raise ValueError(
f"Model architectures {architectures} are not supported for now. "
f"Supported architectures: {list(_MODEL_REGISTRY.keys())}")
def get_model(model_config: ModelConfig) -> nn.Module:
model_class = _get_model_architecture(model_config.hf_config)
with _set_default_torch_dtype(model_config.dtype):
# Create a model instance.
# The weights will be initialized as empty tensors.
model = model_class(model_config.hf_config)
if model_config.use_dummy_weights:
model = model.cuda()
# NOTE(woosuk): For accurate performance evaluation, we assign
# random values to the weights.
initialize_dummy_weights(model)
else:
# Load the weights from the cached or downloaded files.
model.load_weights(model_config.model, model_config.download_dir,
model_config.use_np_weights)
model = model.cuda()
return model.eval()