from typing import Any, Callable, Dict, List, Optional, Union import torch import torch.nn as nn from transformers import BloomForCausalLM, LlamaForCausalLM from transformers.generation import GenerationConfig from transformers.generation.stopping_criteria import StoppingCriteriaList from transformers.tokenization_utils_base import BatchEncoding from colossalai.shardformer import ShardConfig, ShardFormer from colossalai.shardformer.policies.auto_policy import get_autopolicy from .batch_infer_state import BatchInferState from .kvcache_manager import MemoryManager DP_AXIS, PP_AXIS, TP_AXIS = 0, 1, 2 _supported_models = ['LlamaForCausalLM', 'LlamaModel', 'BloomForCausalLM'] class TPInferEngine: """Engine class for tensor parallel inference. Args: model (Module): original model, e.g. huggingface CausalLM shard_config (ShardConfig): The config for sharding original model max_batch_size (int): maximum batch size max_input_len (int): maximum input length of sequence max_output_len (int): maximum output length of output tokens dtype (torch.dtype): datatype used to init KV cache space device (str): device the KV cache of engine to be initialized on Examples: >>> # define model and shard config for your inference >>> model = ... >>> generate_kwargs = ... >>> shard_config = ShardConfig(enable_tensor_parallelism=True, inference_only=True) >>> infer_engine = TPInferEngine(model, shard_config, MAX_BATCH_SIZE, MAX_INPUT_LEN, MAX_OUTPUT_LEN) >>> outputs = infer_engine.generate(input_ids, **generate_kwargs) """ def __init__(self, model: nn.Module, shard_config: ShardConfig, max_batch_size: int, max_input_len: int, max_output_len: int, dtype: torch.dtype = torch.float16, device: str = 'cuda') -> None: self.max_batch_size = max_batch_size self.max_input_len = max_input_len self.max_output_len = max_output_len self.max_total_token_num = self.max_batch_size * (self.max_input_len + self.max_output_len) # Constraints relatable with specs of devices and model # This may change into an optional arg in the future assert self.max_batch_size <= 64, "Max batch size exceeds the constraint" assert self.max_input_len + self.max_output_len <= 4096, "Max length exceeds the constraint" self.dtype = dtype self.head_dim = model.config.hidden_size // model.config.num_attention_heads self.head_num = model.config.num_attention_heads self.layer_num = model.config.num_hidden_layers self.tp_size = -1 # to be set with given shard config in self.prepare_shard_config self.cache_manager = None self.shard_config = shard_config self.model = None # optimize the original model by sharding with ShardFormer self._optimize_model(model=model.to(device)) def _init_manager(self) -> None: assert self.tp_size >= 1, "TP size not initialized without providing a valid ShardConfig" assert self.head_num % self.tp_size == 0, f"Cannot shard {self.head_num} heads with tp size {self.tp_size}" self.head_num //= self.tp_size # update sharded number of heads self.cache_manager = MemoryManager(self.max_total_token_num, self.dtype, self.head_num, self.head_dim, self.layer_num) def _optimize_model(self, model: nn.Module) -> None: """ Optimize the original model by sharding with ShardFormer. In further generation, use the sharded model instead of original model. """ # NOTE we will change to use an inference config later with additional attrs we want assert self.shard_config.inference_only is True shardformer = ShardFormer(shard_config=self.shard_config) self._prepare_with_shard_config(shard_config=self.shard_config) self._shard_model_by(shardformer, model) def _prepare_with_shard_config(self, shard_config: Optional[ShardConfig] = None) -> ShardConfig: """ Prepare the engine with a given ShardConfig. Args: shard_config (ShardConfig): shard config given to specify settings of the engine. If not provided, a default ShardConfig with tp size 1 will be created. """ self.tp_size = 1 if shard_config is None: shard_config = ShardConfig( tensor_parallel_process_group=None, pipeline_stage_manager=None, enable_tensor_parallelism=False, enable_fused_normalization=False, enable_all_optimization=False, enable_flash_attention=False, enable_jit_fused=False, inference_only=True, ) else: shard_config.inference_only = True shard_config.pipeline_stage_manager = None if shard_config.enable_tensor_parallelism: self.tp_size = shard_config.tensor_parallel_size self._init_manager() return shard_config def _shard_model_by(self, shardformer: ShardFormer, model: nn.Module) -> None: """ Shard original model by the given ShardFormer and store the sharded model. """ assert self.tp_size == shardformer.shard_config.tensor_parallel_size, \ "Discrepancy between the tp size of TPInferEngine and the tp size of shard config" model_name = model.__class__.__name__ assert model_name in self.supported_models, f"Unsupported model cls {model_name} for TP inference." policy = get_autopolicy(model, inference_only=True) self.model, _ = shardformer.optimize(model, policy) self.model = self.model.cuda() @property def supported_models(self) -> List[str]: return _supported_models def generate(self, input_tokens: Union[BatchEncoding, dict, list, torch.Tensor], **generate_kwargs) -> torch.Tensor: """Generate token sequence. Args: input_tokens: could be one of the following types 1. BatchEncoding or dict (e.g. tokenizer batch_encode) 2. list of input token ids (e.g. appended result of tokenizer encode) 3. torch.Tensor (e.g. tokenizer encode with return_tensors='pt') Returns: torch.Tensor: The returned sequence is given inputs + generated_tokens. """ if isinstance(input_tokens, torch.Tensor): input_tokens = dict(input_ids=input_tokens, attention_mask=torch.ones_like(input_tokens, dtype=torch.bool)) for t in input_tokens: if torch.is_tensor(input_tokens[t]): input_tokens[t] = input_tokens[t].cuda() if 'max_new_tokens' not in generate_kwargs: generate_kwargs.update(max_new_tokens=self.max_output_len) return self._generate_by_set_infer_state(input_tokens, **generate_kwargs) def prepare_batch_state(self, inputs) -> BatchInferState: """ Create and prepare BatchInferState used for inference during model forwrad, by processing each sequence of the given inputs. Args: inputs: should be one of the following types 1. BatchEncoding or dict (e.g. tokenizer batch_encode) 2. list of input token ids (e.g. appended result of tokenizer encode) 3. torch.Tensor (e.g. tokenizer encode with return_tensors='pt') NOTE For torch.Tensor inputs representing a batch of inputs, we are unable to retrieve the actual length (e.g. number of tokens) of each input without attention mask Hence, for torch.Tensor with shape [bs, l] where bs > 1, we will assume all the inputs in the batch has the maximum length l Returns: BatchInferState: the states for the current batch during inference """ if not isinstance(inputs, (BatchEncoding, dict, list, torch.Tensor)): raise TypeError(f"inputs type {type(inputs)} is not supported in prepare_batch_state") input_ids_list = None attention_mask = None if isinstance(inputs, (BatchEncoding, dict)): input_ids_list = inputs['input_ids'] attention_mask = inputs['attention_mask'] else: input_ids_list = inputs if isinstance(input_ids_list[0], int): # for a single input input_ids_list = [input_ids_list] attention_mask = [attention_mask] if attention_mask is not None else attention_mask batch_size = len(input_ids_list) seq_start_indexes = torch.zeros(batch_size, dtype=torch.int32, device='cuda') seq_lengths = torch.zeros(batch_size, dtype=torch.int32, device='cuda') start_index = 0 max_len_in_batch = -1 if isinstance(inputs, (BatchEncoding, dict)): for i, attn_mask in enumerate(attention_mask): curr_seq_len = len(attn_mask) # if isinstance(attn_mask, torch.Tensor): # curr_seq_len = int(torch.sum(attn_mask)) # else: # curr_seq_len = int(sum(attn_mask)) seq_lengths[i] = curr_seq_len seq_start_indexes[i] = start_index start_index += curr_seq_len max_len_in_batch = curr_seq_len if curr_seq_len > max_len_in_batch else max_len_in_batch else: length = max(len(input_id) for input_id in input_ids_list) for i, input_ids in enumerate(input_ids_list): curr_seq_len = length seq_lengths[i] = curr_seq_len seq_start_indexes[i] = start_index start_index += curr_seq_len max_len_in_batch = curr_seq_len if curr_seq_len > max_len_in_batch else max_len_in_batch block_loc = torch.empty((batch_size, self.max_input_len + self.max_output_len), dtype=torch.long, device='cuda') batch_infer_state = BatchInferState(batch_size, max_len_in_batch) batch_infer_state.seq_len = seq_lengths.to('cuda') batch_infer_state.start_loc = seq_start_indexes.to('cuda') batch_infer_state.block_loc = block_loc batch_infer_state.decode_layer_id = 0 batch_infer_state.past_key_values_len = 0 batch_infer_state.is_context_stage = True batch_infer_state.set_cache_manager(self.cache_manager) return batch_infer_state @torch.no_grad() def _generate_by_set_infer_state(self, input_tokens, **generate_kwargs) -> torch.Tensor: """ Generate output tokens by setting BatchInferState as an attribute to the model and calling model.generate Args: inputs: should be one of the following types 1. BatchEncoding or dict (e.g. tokenizer batch_encode) 2. list of input token ids (e.g. appended result of tokenizer encode) 3. torch.Tensor (e.g. tokenizer encode with return_tensors='pt') """ # for testing, always use sharded model assert self.model is not None, "sharded model does not exist" batch_infer_state = self.prepare_batch_state(input_tokens) assert batch_infer_state.max_len_in_batch <= self.max_input_len, "max length in batch exceeds limit" # set BatchInferState for the current batch as attr to model # NOTE this is not a preferable way to pass BatchInferState during inference # we might want to rewrite generate function (e.g. _generate_by_pass_infer_state) # and pass BatchInferState via model forward model = self.model if isinstance(model, LlamaForCausalLM): model = self.model.model elif isinstance(model, BloomForCausalLM): model = self.model.transformer setattr(model, 'infer_state', batch_infer_state) outputs = self.model.generate(**input_tokens, **generate_kwargs, early_stopping=False) # NOTE In future development, we're going to let the scheduler to handle the cache, # instead of freeing space explicitly at the end of generation self.cache_manager.free_all() return outputs # TODO might want to implement the func that generates output tokens by passing BatchInferState # as an arg into model.forward. # It requires rewriting model generate and replacing model forward. @torch.no_grad() def _generate_by_pass_infer_state(self, input_tokens, max_out_length: int, generation_config: Optional[GenerationConfig] = None, stopping_criteria: Optional[StoppingCriteriaList] = None, prepare_inputs_fn: Optional[Callable[[torch.Tensor, Any], dict]] = None, **model_kwargs) -> torch.Tensor: raise NotImplementedError("generate by passing BatchInferState is not implemented.") # might want to use in rewritten generate method: use after model.forward # BatchInferState is created and kept during generation # after each iter of model forward, we should update BatchInferState def _update_batch_state(self, infer_state: Optional[BatchInferState]) -> None: batch_size = infer_state.batch_size device = infer_state.start_loc.device infer_state.start_loc = infer_state.start_loc + torch.arange(0, batch_size, dtype=torch.int32, device=device) infer_state.seq_len += 1 # might want to create a sequence pool # add a single request/sequence/input text at a time and record its length # In other words, store the actual length of input tokens representing a single input text # E.g. "Introduce landmarks in Beijing" # => add request # => record token length and other necessary information to be used # => engine hold all these necessary information until `generate` (or other name) is called, # => put information already recorded in batchinferstate and pass it to model forward # => clear records in engine def add_request(): raise NotImplementedError()