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petals/src/petals/bloom/from_pretrained.py

87 lines
3.4 KiB
Python

"""
Utils for fetching pretrained model parts. Currently, this relies on huggingface transformers' from_pretrained code.
If necessary, one can rewrite this to implement a different behavior, such as:
- loading files from a local data source (e.g. S3)
- load files via BitTorrent ( https://pypi.org/project/libtorrent/ ) or IPFS( https://docs.ipfs.io/how-to )
- fetch the weights over IPoAC, using a fleet of trained pigeons ( http://www.faqs.org/rfcs/rfc1149.html )
"""
from __future__ import annotations
from typing import Optional, OrderedDict, Union
import torch
from hivemind.utils.logging import get_logger, use_hivemind_log_handler
from transformers.modeling_utils import WEIGHTS_NAME
from transformers.utils.hub import cached_path, hf_bucket_url
from petals.bloom import BloomBlock, BloomConfig
use_hivemind_log_handler("in_root_logger")
logger = get_logger(__file__)
CLIENT_BRANCH = "main"
BLOCK_BRANCH_PREFIX = "block_"
USER_AGENT = {"file_type": "model", "framework": "pytorch", "from_auto_class": False}
FORCE_DOWNLOAD = False
RESUME_DOWNLOAD = False
LOCAL_FILES_ONLY = False
def load_pretrained_block(
converted_model_name_or_path: str,
block_index: int,
config: Optional[BloomConfig] = None,
torch_dtype: Union[torch.dtype, str] = "auto",
use_auth_token: Optional[str] = None,
cache_dir: Optional[str] = None,
) -> BloomBlock:
"""Load one BloomBlock from a converted model. See convert_model.py (or README.md) on how to convert it."""
if config is None:
config = BloomConfig.from_pretrained(converted_model_name_or_path, use_auth_token=use_auth_token)
block = BloomBlock(config, layer_number=block_index)
state_dict = _load_state_dict(
converted_model_name_or_path, block_index, use_auth_token=use_auth_token, cache_dir=cache_dir
)
block.load_state_dict(state_dict)
if torch_dtype == "auto":
with torch.no_grad():
for name, param in block.named_parameters():
assert name in state_dict, f"{name} not in state dict"
param.data = param.data.to(state_dict[name].dtype)
else:
assert torch_dtype in DTYPE_MAP.values(), f"torch_dtype must be one of {list(DTYPE_MAP.values())}"
block = block.to(dtype=torch_dtype)
report = block.load_state_dict(state_dict, strict=True)
logger.info(f"Loaded {converted_model_name_or_path} block {block_index}, {report}")
return block
def _load_state_dict(
pretrained_model_name_or_path: str,
block_index: Optional[int] = None,
use_auth_token: Optional[str] = None,
cache_dir: Optional[str] = None,
) -> OrderedDict[str, torch.Tensor]:
revision = BLOCK_BRANCH_PREFIX + str(block_index) if block_index is not None else CLIENT_BRANCH
archive_file = hf_bucket_url(pretrained_model_name_or_path, filename=WEIGHTS_NAME, revision=revision, mirror=None)
# Load from URL or cache if already cached
resolved_archive_file = cached_path(
archive_file,
cache_dir=cache_dir,
force_download=FORCE_DOWNLOAD,
proxies=None,
resume_download=RESUME_DOWNLOAD,
local_files_only=LOCAL_FILES_ONLY,
use_auth_token=use_auth_token,
user_agent=USER_AGENT,
)
state_dict = torch.load(resolved_archive_file, map_location="cpu")
return state_dict
DTYPE_MAP = dict(bfloat16=torch.bfloat16, float16=torch.float16, float32=torch.float32, auto="auto")