import os import traceback from pathlib import Path from typing import Any, Dict, Optional, Union import torch from exllamav2 import ( ExLlamaV2, ExLlamaV2Cache, ExLlamaV2Cache_8bit, ExLlamaV2Config ) from torch.nn import CrossEntropyLoss from transformers import GenerationConfig, PretrainedConfig, PreTrainedModel from transformers.modeling_outputs import CausalLMOutputWithPast from modules import shared from modules.logging_colors import logger try: import flash_attn except ModuleNotFoundError: logger.warning( 'You are running ExLlamaV2 without flash-attention. This will cause the VRAM usage ' 'to be a lot higher than it could be.\n' 'Try installing flash-attention following the instructions here: ' 'https://github.com/Dao-AILab/flash-attention#installation-and-features' ) pass except Exception: logger.warning('Failed to load flash-attention due to the following error:\n') traceback.print_exc() class Exllamav2HF(PreTrainedModel): def __init__(self, config: ExLlamaV2Config): super().__init__(PretrainedConfig()) self.ex_config = config self.loras = None self.generation_config = GenerationConfig() self.ex_model = ExLlamaV2(config) if not shared.args.autosplit: split = None if shared.args.gpu_split: split = [float(alloc) for alloc in shared.args.gpu_split.split(",")] self.ex_model.load(split) if shared.args.cache_8bit: self.ex_cache = ExLlamaV2Cache_8bit(self.ex_model, lazy=shared.args.autosplit) else: self.ex_cache = ExLlamaV2Cache(self.ex_model, lazy=shared.args.autosplit) if shared.args.autosplit: self.ex_model.load_autosplit(self.ex_cache) self.past_seq = None if shared.args.cfg_cache: if shared.args.cache_8bit: self.ex_cache_negative = ExLlamaV2Cache_8bit(self.ex_model) else: self.ex_cache_negative = ExLlamaV2Cache(self.ex_model) self.past_seq_negative = None def _validate_model_class(self): pass def _validate_model_kwargs(self, model_kwargs: Dict[str, Any]): pass def prepare_inputs_for_generation(self, input_ids, **kwargs): return {'input_ids': input_ids, **kwargs} @property def device(self) -> torch.device: return torch.device(0) def __call__(self, *args, **kwargs): use_cache = kwargs.get('use_cache', True) labels = kwargs.get('labels', None) past_key_values = kwargs.get('past_key_values', None) if len(args) > 0: if not shared.args.cfg_cache: logger.error("Please enable the cfg-cache option to use CFG with ExLlamav2_HF.") return input_ids = args[0] is_negative = True past_seq = self.past_seq_negative ex_cache = self.ex_cache_negative else: input_ids = kwargs['input_ids'] is_negative = False past_seq = self.past_seq ex_cache = self.ex_cache seq = input_ids[0].tolist() if is_negative and past_key_values is not None: seq = past_key_values + seq seq_tensor = torch.tensor(seq) reset = True # Make the forward call if labels is None: if past_seq is not None: min_length = min(past_seq.shape[0], seq_tensor.shape[0]) indices = torch.nonzero(~torch.eq(past_seq[:min_length], seq_tensor[:min_length])) if len(indices) > 0: longest_prefix = indices[0].item() else: longest_prefix = min_length if longest_prefix > 0: reset = False ex_cache.current_seq_len = longest_prefix if len(seq_tensor) - longest_prefix > 1: self.ex_model.forward(seq_tensor[longest_prefix:-1].view(1, -1), ex_cache, preprocess_only=True, loras=self.loras) elif len(seq_tensor) == longest_prefix: # Very tricky: if the prefix we are reusing *is* the input_ids, then we have to back up the cache pointer by one, # because we feed input_ids[-1] to forward() below, but that last token is already in the cache! ex_cache.current_seq_len -= 1 if reset: ex_cache.current_seq_len = 0 if len(seq_tensor) > 1: self.ex_model.forward(seq_tensor[:-1].view(1, -1), ex_cache, preprocess_only=True, loras=self.loras) logits = self.ex_model.forward(seq_tensor[-1:].view(1, -1), ex_cache, loras=self.loras).to(input_ids.device).float() else: ex_cache.current_seq_len = 0 logits = self.ex_model.forward(seq_tensor.view(1, -1), ex_cache, last_id_only=False, loras=self.loras).float() if is_negative: self.past_seq_negative = seq_tensor else: self.past_seq = seq_tensor loss = None if labels is not None: # Shift so that tokens < n predict n shift_logits = logits[..., :-1, :].contiguous() shift_labels = labels[..., 1:].contiguous() # Flatten the tokens loss_fct = CrossEntropyLoss() shift_logits = shift_logits.view(-1, logits.shape[-1]) shift_labels = shift_labels.view(-1) # Enable model parallelism shift_labels = shift_labels.to(shift_logits.device) loss = loss_fct(shift_logits, shift_labels) return CausalLMOutputWithPast(logits=logits, past_key_values=seq if use_cache else None, loss=loss) @classmethod def from_pretrained(cls, pretrained_model_name_or_path: Optional[Union[str, os.PathLike]], *model_args, **kwargs): assert len(model_args) == 0 and len(kwargs) == 0, "extra args is currently not supported" if isinstance(pretrained_model_name_or_path, str): pretrained_model_name_or_path = Path(pretrained_model_name_or_path) pretrained_model_name_or_path = Path(f'{shared.args.model_dir}') / Path(pretrained_model_name_or_path) config = ExLlamaV2Config() config.model_dir = str(pretrained_model_name_or_path) config.prepare() config.max_seq_len = shared.args.max_seq_len config.scale_pos_emb = shared.args.compress_pos_emb config.scale_alpha_value = shared.args.alpha_value config.no_flash_attn = shared.args.no_flash_attn config.num_experts_per_token = int(shared.args.num_experts_per_token) return Exllamav2HF(config)