import os import traceback from pathlib import Path from typing import Any, Dict, Optional, Union import torch from exllamav3 import Cache, Config, Model from exllamav3.cache import CacheLayer_fp16, CacheLayer_quant from torch.nn import CrossEntropyLoss from transformers import ( GenerationConfig, GenerationMixin, PretrainedConfig, PreTrainedModel ) from transformers.modeling_outputs import CausalLMOutputWithPast from modules import shared from modules.logging_colors import logger try: import flash_attn except Exception: logger.warning('Failed to load flash-attention due to the following error:\n') traceback.print_exc() class Exllamav3HF(PreTrainedModel, GenerationMixin): def __init__(self, model_dir): super().__init__(PretrainedConfig()) self.generation_config = GenerationConfig() config = Config.from_directory(model_dir) self.ex_model = Model.from_config(config) # Calculate the closest multiple of 256 at or above the chosen value max_tokens = shared.args.ctx_size if max_tokens % 256 != 0: adjusted_tokens = ((max_tokens // 256) + 1) * 256 logger.warning(f"max_num_tokens must be a multiple of 256. Adjusting from {max_tokens} to {adjusted_tokens}") max_tokens = adjusted_tokens # Parse cache type cache_type = shared.args.cache_type.lower() cache_kwargs = {} if cache_type == 'fp16': layer_type = CacheLayer_fp16 elif cache_type.startswith('q'): layer_type = CacheLayer_quant if '_' in cache_type: # Different bits for k and v (e.g., q4_q8) k_part, v_part = cache_type.split('_') k_bits = int(k_part[1:]) v_bits = int(v_part[1:]) else: # Same bits for k and v (e.g., q4) k_bits = v_bits = int(cache_type[1:]) # Validate bit ranges if not (2 <= k_bits <= 8 and 2 <= v_bits <= 8): logger.warning(f"Invalid quantization bits: k_bits={k_bits}, v_bits={v_bits}. Must be between 2 and 8. Falling back to fp16.") layer_type = CacheLayer_fp16 else: cache_kwargs = {'k_bits': k_bits, 'v_bits': v_bits} else: logger.warning(f"Unrecognized cache type: {cache_type}. Falling back to fp16.") layer_type = CacheLayer_fp16 self.ex_cache = Cache(self.ex_model, max_num_tokens=max_tokens, layer_type=layer_type, **cache_kwargs) # Create load parameters dictionary load_params = {'progressbar': True} if shared.args.gpu_split: split = [float(alloc) for alloc in shared.args.gpu_split.split(",")] load_params['use_per_device'] = split self.ex_model.load(**load_params) self.past_seq = None self.max_tokens = max_tokens 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 ExLlamav3_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 current_len = longest_prefix if len(seq_tensor) - longest_prefix > 1: self.ex_model.forward( input_ids=seq_tensor[longest_prefix:-1].view(1, -1), params={ "attn_mode": "flash_attn", "cache": ex_cache, "past_len": longest_prefix, "batch_shape": (1, self.max_tokens) } ) current_len = longest_prefix + len(seq_tensor) - longest_prefix - 1 if reset: if len(seq_tensor) > 1: self.ex_model.forward( input_ids=seq_tensor[:-1].view(1, -1), params={ "attn_mode": "flash_attn", "cache": ex_cache, "past_len": 0, "batch_shape": (1, self.max_tokens) } ) current_len = len(seq_tensor) - 1 else: current_len = 0 logits = self.ex_model.forward( input_ids=seq_tensor[-1:].view(1, -1), params={ "attn_mode": "flash_attn", "cache": ex_cache, "past_len": current_len, "batch_shape": (1, self.max_tokens) } ).to(input_ids.device).float() else: logits = self.ex_model.forward( input_ids=seq_tensor.view(1, -1), params={ "attn_mode": "flash_attn", "cache": ex_cache, "past_len": 0, "batch_shape": (1, self.max_tokens) } ).float() if is_negative: self.past_seq_negative = seq_tensor else: self.past_seq = seq_tensor if torch.cuda.is_available(): torch.cuda.synchronize() 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) return Exllamav3HF(pretrained_model_name_or_path)