import torch import torch.distributed from typing import List, Optional, Tuple from accelerate import init_empty_weights from safetensors import safe_open from transformers import ( AutoTokenizer, AutoModelForCausalLM, AutoConfig, ) from transformers.models.opt.parallel_layers import ( TensorParallelColumnLinear, TensorParallelEmbedding, TensorParallelRowLinear, ) from text_generation_server.models import CausalLM from text_generation_server.utils import ( initialize_torch_distributed, weight_files, ) HAS_BITS_AND_BYTES = True try: import bitsandbytes as bnb from bitsandbytes.nn import Int8Params except Exception as e: HAS_BITS_AND_BYTES = False class OPT(CausalLM): def forward( self, input_ids, attention_mask, position_ids, past_key_values: Optional = None ) -> Tuple[torch.Tensor, List[Tuple[torch.Tensor, torch.Tensor]]]: """Overwrite forward to ignore position_ids""" # Model Forward outputs = self.model.forward( input_ids=input_ids, attention_mask=attention_mask, past_key_values=past_key_values, use_cache=True, ) return outputs.logits, outputs.past_key_values class OPTSharded(OPT): def __init__( self, model_id: str, revision: Optional[str] = None, quantize: bool = False ): self.process_group, self.rank, self.world_size = initialize_torch_distributed() self.master = self.rank == 0 if torch.cuda.is_available(): device = torch.device(f"cuda:{self.rank}") dtype = torch.bfloat16 if torch.cuda.is_bf16_supported() else torch.float32 else: device = torch.device("cpu") dtype = torch.float32 tokenizer = AutoTokenizer.from_pretrained( model_id, revision=revision, padding_side="left", truncation_side="left" ) config = AutoConfig.from_pretrained( model_id, revision=revision, tp_parallel=True ) tokenizer.pad_token_id = config.pad_token_id torch.distributed.barrier(group=self.process_group) filenames = weight_files(model_id, revision=revision, extension=".safetensors") with init_empty_weights(): model = AutoModelForCausalLM.from_config(config) torch.distributed.barrier(group=self.process_group) self.load_weights( model, filenames, quantize=quantize, device=device, dtype=dtype, rank=self.rank, world_size=self.world_size, ) self.model = model.eval() torch.distributed.barrier(group=self.process_group) super(CausalLM, self).__init__( tokenizer=tokenizer, requires_padding=True, dtype=dtype, device=device, ) @staticmethod def load_weights( model, filenames: List[str], quantize: bool, device: torch.device, dtype: torch.dtype, rank: int, world_size: int, ): parameters = dict(model.named_parameters()) for file in filenames: with safe_open( file, framework="pt", device=str(device) if not quantize else "cpu" ) as f: for name in f.keys(): if name == "lm_head.weight": continue module_name, param_name = name.rsplit(".", 1) module = model.get_submodule(module_name) current_tensor = parameters[name] slice_ = f.get_slice(name) if isinstance(module, TensorParallelColumnLinear): size = slice_.get_shape()[0] block_size = size // world_size start = rank * block_size stop = (rank + 1) * block_size tensor = slice_[start:stop] elif isinstance(module, TensorParallelRowLinear): if param_name == "weight": size = slice_.get_shape()[1] block_size = size // world_size start = rank * block_size stop = (rank + 1) * block_size tensor = slice_[:, start:stop] else: tensor = slice_[:] # XXX: Hack for Rowlinear to add the bias only once. if rank != 0: tensor = torch.zeros_like(tensor) elif isinstance(module, TensorParallelEmbedding): size = slice_.get_shape()[0] block_size = size // world_size start = rank * block_size stop = (rank + 1) * block_size tensor = slice_[start:stop] else: tensor = slice_[:] if current_tensor.shape != tensor.shape: raise ValueError( f"Name {name} -- Current {current_tensor.shape} and got {tensor.shape}" ) tensor = tensor.contiguous().to(dtype) if quantize: if not HAS_BITS_AND_BYTES: raise ImportError( "bitsandbytes is not available on your machine either because it is not installed " "or you don't have a GPU.\n" "You can install it with `pip install bitsandbytes`." ) if ( type(module) in [TensorParallelRowLinear, TensorParallelColumnLinear] and param_name == "weight" ): tensor = Int8Params( tensor, has_fp16_weights=False, requires_grad=False, ).to(device) state = bnb.MatmulLtState() state.threshold = 6.0 state.has_fp16_weights = False state.memory_efficient_backward = False state.use_pool = True state.CB = tensor.CB state.SCB = tensor.SCB tensor.CB = None tensor.SCB = None def replace_linear(state): def linear(input, weight, bias): out = bnb.matmul( input, weight, state=state, threshold=state.threshold, bias=bias, ) if state.CB is not None: # we converted 8-bit row major to turing/ampere format # in the first inference pass # we no longer need the row-major weight del state.CB weight.data = state.CxB return out return linear module.linear = replace_linear(state) else: tensor = tensor.to(device) module._parameters[param_name] = tensor if name == "model.decoder.embed_tokens.weight": model.lm_head._parameters["weight"] = tensor uninitialized_parameters = [] for n, p in model.named_parameters(): if p.data.device == torch.device("meta"): uninitialized_parameters.append(n) if uninitialized_parameters: raise RuntimeError( f"found uninitialized parameters in model: {uninitialized_parameters}" ) def forward( self, input_ids, attention_mask, position_ids, past_key_values: Optional = None ): outputs = self.model.forward( input_ids=input_ids, attention_mask=attention_mask, past_key_values=past_key_values, use_cache=True, ) # Logits are sharded, so we need to gather them logits = [torch.empty_like(outputs.logits) for _ in range(self.world_size)] torch.distributed.all_gather(logits, outputs.logits, group=self.process_group) logits = torch.cat(logits, dim=2) return logits, outputs.past_key_values