"""A weight loader for HuggingFace's PyTorch format""" import gc import json from collections import OrderedDict, defaultdict from collections.abc import Iterator from pathlib import Path from typing import Callable, Dict, List, Optional, Tuple # noqa: UP035 import numpy as np from tqdm import tqdm from tvm.runtime import Device, Tensor from tvm.runtime import tensor as as_tensor from mlc_llm.support import logging from mlc_llm.support.preshard import _sharded_param_name from mlc_llm.support.style import bold from .mapping import ExternMapping, QuantizeMapping from .stats import Stats from .utils import check_parameter_usage, load_safetensor_shard, load_torch_shard logger = logging.getLogger(__name__) class HuggingFaceLoader: """A loader loading HuggingFace's PyTorch/SafeTensor format and converts them to MLC's parameters. Attributes ---------- stats : Stats Statistics of the loading process. extern_param_map : ExternMapping The parameter mapping from MLC to HuggingFace PyTorch/SafeTensor. torch_to_path : Dict[str, Path] A mapping from PyTorch/SafeTensor parameter name to the path of the file containing it, or the path meaning all parameters are stored in a single file. cached_files : Dict[Path, Dict[str, np.ndarray]] A cache of the loaded files. The key is the path of the file, and the value is a mapping from parameter name to the parameter value. quantize_param_map : Optional[QuantizeMapping] The quantization mapping from MLC to quantized MLC parameters. """ stats: Stats cached_files: Dict[Path, Dict[str, np.ndarray]] # noqa: UP006 torch_to_path: Dict[str, Path] # noqa: UP006 extern_param_map: ExternMapping quantize_param_map: Optional[QuantizeMapping] def __init__( self, path: Path, extern_param_map: ExternMapping, quantize_param_map: Optional[QuantizeMapping] = None, ) -> None: """Create a parameter loader from HuggingFace PyTorch format. Parameters ---------- path : pathlib.Path Path to either a JSON indexing file, or a PyTorch bin file. 1) For JSON indexing file, it is usually `pytorch_model.bin.index.json` or `model.safetensors.index.json` in the repo, which contains a `weight_map` that maps each PyTorch parameter to the file containing the weight. 2) For PyTorch bin file, it is usually `pytorch_model.bin` in the repo, which contains all the parameters. 3) For safetensor file, it is usually `model.safetensors` in the repo, which contains all the parameters. extern_param_map : ExternMapping Maps an MLC parameter to a list of PyTorch/SafeTensor parameters. quantize_param_map: Optional[QuantizeMapping] The quantization mapping from MLC to quantized MLC parameters, default to None, which means no quantization. """ assert path.is_file(), f"Path {path} is not a file" self.stats = Stats() self.extern_param_map = extern_param_map self.cached_files = {} self.torch_to_path = {} self.quantize_param_map = quantize_param_map if path.suffix in (".bin", ".safetensors", ".pt"): self._load_file(path) for name in self.cached_files[path].keys(): self.torch_to_path[name] = path elif path.suffix == ".json": with path.open("r", encoding="utf-8") as in_file: torch_weight_map = json.load(in_file)["weight_map"] for torch_name, path_str in torch_weight_map.items(): self.torch_to_path[torch_name] = path.parent / path_str else: raise FileNotFoundError(f"Unknown file suffix: {path}") check_parameter_usage(extern_param_map, set(self.torch_to_path.keys())) def load( self, device: Device, preshard_funcs: Optional[Dict[str, Callable]] = None, # noqa: UP006 ) -> Iterator[Tuple[str, Tensor]]: # noqa: UP006 """Load the parameters and yield the MLC parameter and its value. Parameters ---------- device : Optional[Device] The device to store the parameter, default to None, which means using CPU. Yields ------ Tuple[str, Tensor] The MLC parameter name and its value, quantized if quantization mapping is provided. """ mlc_names = _loading_order(self.extern_param_map, self.torch_to_path) for mlc_name in tqdm(mlc_names): param = self._load_mlc_param(mlc_name, device=device) # Apply quantization if needed, in this case the original parameter may become # multiple quantized parameters. for name, loader_param in self._load_or_quantize(mlc_name, param, device): # Apply presharding if needed if preshard_funcs is not None and name in preshard_funcs: for shard_id, shard_param in enumerate(preshard_funcs[name](loader_param)): yield _sharded_param_name(name, shard_id), shard_param else: yield name, loader_param cached_files = list(self.cached_files.keys()) for path in cached_files: self._unload_file(path) self.stats.log_time_info("HF") self.stats.log_mem_usage() def _load_mlc_param(self, mlc_name: str, device: Optional[Device]) -> Tensor: torch_names = self.extern_param_map.param_map[mlc_name] files_required = {self.torch_to_path[p] for p in torch_names} files_existing = set(self.cached_files.keys()) files_to_load = files_required - files_existing files_to_unload = files_existing - files_required # Step 1. When there is some file to unloaded: # - If no pending file load: unloading is deferred as there is no gain in peak memory usage; # - Need to load files: unload immediately to save memory and make space for the new files. if files_to_load: for path in files_to_unload: self._unload_file(path) # Step 2. Load all the files needed for path in files_to_load: self._load_file(path) # Step 3. Collect all torch parameters in order torch_params = [self.cached_files[self.torch_to_path[i]][i] for i in torch_names] # Step 4. Apply the mapping function with self.stats.timer("map_time_sec"): param = self.extern_param_map.map_func[mlc_name](*torch_params) if device: return as_tensor(param, device=device) return as_tensor(param) def _load_or_quantize(self, mlc_name, param, device: Device): if self.quantize_param_map and mlc_name in self.quantize_param_map.param_map: with self.stats.timer("quant_time_sec"): q_names = self.quantize_param_map.param_map[mlc_name] q_params = self.quantize_param_map.map_func[mlc_name](param) device.sync() for q_name, q_param in zip(q_names, q_params): logger.info( '[Quantized] Parameter: "%s", shape: %s, dtype: %s', bold(q_name), q_param.shape, q_param.dtype, ) yield q_name, q_param else: logger.info( '[Not quantized] Parameter: "%s", shape: %s, dtype: %s', bold(mlc_name), param.shape, param.dtype, ) device.sync() yield mlc_name, param def _load_file(self, path: Path) -> None: logger.info("Loading HF parameters from: %s", path) load_func = load_safetensor_shard if path.suffix == ".safetensors" else load_torch_shard with self.stats.timer("load_time_sec"): result = {} for name, param in load_func(path): result[name] = param self.stats.mem_add(param.nbytes) if name not in self.extern_param_map.unused_params: self.stats.total_param_num += param.size self.cached_files[path] = result def _unload_file(self, path: Path) -> None: logger.info("Unloading HF weight file: %s", path) with self.stats.timer("load_time_sec"): for _, param in self.cached_files[path].items(): self.stats.mem_rm(param.nbytes) del self.cached_files[path] gc.collect() def _loading_order(param_map: ExternMapping, torch_to_path: Dict[str, Path]) -> List[str]: # noqa: UP006 # Step 1. Build a map from path to torch parameters path_to_torch: Dict[Path, List[str]] = defaultdict(list) # noqa: UP006 for torch_name, path in torch_to_path.items(): path_to_torch[path].append(torch_name) # Step 2. Build a map from torch parameters to MLC parameters torch_to_mlc = defaultdict(list) for mlc_name, torch_names in param_map.param_map.items(): for torch_name in torch_names: torch_to_mlc[torch_name].append(mlc_name) # Step 3. Construct the ordering that ensures file locality order = OrderedDict() for _, torch_names in path_to_torch.items(): for torch_name in torch_names: for mlc_name in torch_to_mlc[torch_name]: if mlc_name not in order: order[mlc_name] = 1 return list(order.keys()) __all__ = ["HuggingFaceLoader"]