import torch from dataclasses import dataclass from opentelemetry import trace from transformers import AutoTokenizer, AutoModelForSeq2SeqLM, PreTrainedTokenizerBase from typing import Optional, Tuple, List, Type, Dict from text_generation_server.models import Model from text_generation_server.models.types import ( GeneratedText, Batch, Generation, PrefillTokens, ) from text_generation_server.pb import generate_pb2 from text_generation_server.utils import NextTokenChooser, StoppingCriteria, Sampling tracer = trace.get_tracer(__name__) @dataclass class Seq2SeqLMBatch(Batch): batch_id: int requests: List[generate_pb2.Request] requests_idx_mapping: Dict[int, int] # Encoder values input_ids: Optional[torch.Tensor] attention_mask: torch.Tensor # Decoder values decoder_input_ids: torch.Tensor decoder_attention_mask: Optional[torch.Tensor] encoder_last_hidden_state: Optional[torch.Tensor] # All tokens all_decoder_input_ids: List[torch.Tensor] # Seq2SeqLM keeps track of both encoder and decoder attention keys and values past_key_values: Optional[List[Tuple]] # Lengths of all generations present in the batch input_lengths: List[int] decoder_input_lengths: List[int] offsets: List[Optional[int]] token_offsets: List[Optional[int]] # Generation helpers next_token_choosers: List[NextTokenChooser] stopping_criterias: List[StoppingCriteria] # Metadata used for padding max_input_length: int max_decoder_input_length: int padding_right_offset: int # Maximum number of tokens this batch will grow to max_tokens: int def to_pb(self) -> generate_pb2.Batch: """Convert a Seq2SeqLMBatch to a text_generation_server.v1.Batch protobuf""" return generate_pb2.Batch( id=self.batch_id, requests=self.requests, size=len(self), max_tokens=self.max_tokens, ) @classmethod def from_pb( cls, pb: generate_pb2.Batch, tokenizer: PreTrainedTokenizerBase, device: torch.device, ) -> "Seq2SeqLMBatch": """Convert a text_generation_server.v1.Batch protobuf to a Seq2SeqLMBatch""" inputs = [] next_token_choosers = [] stopping_criterias = [] decoder_input_lengths = [] offsets = [] token_offsets = [] requests_idx_mapping = {} # Parse batch max_truncation = 0 padding_right_offset = 0 max_decode_tokens = 0 for i, r in enumerate(pb.requests): inputs.append(r.inputs) requests_idx_mapping[r.id] = i decoder_input_lengths.append(1) offsets.append(None) token_offsets.append(None) next_token_choosers.append(NextTokenChooser.from_pb(r.parameters, device)) stopping_criteria = StoppingCriteria.from_pb( r.stopping_parameters, tokenizer ) stopping_criterias.append(stopping_criteria) max_truncation = max(max_truncation, r.truncate) max_decode_tokens += stopping_criteria.max_new_tokens padding_right_offset = max( padding_right_offset, stopping_criteria.max_new_tokens ) # Tokenize batch tokenized_inputs = tokenizer( inputs, return_tensors="pt", padding=True, return_token_type_ids=False, truncation=True, max_length=max_truncation, ).to(device) input_lengths = tokenized_inputs["attention_mask"].sum(1) max_input_length = input_lengths.max() # Decoder sequence only contains the bos_token decoder_input_ids = ( torch.tensor(tokenizer.bos_token_id, device=device) .repeat(len(pb.requests)) .view(-1, 1) ) all_decoder_input_ids = decoder_input_ids.view(-1).split(1) max_tokens = len(inputs) * max_input_length + max_decode_tokens return cls( batch_id=pb.id, requests=pb.requests, requests_idx_mapping=requests_idx_mapping, input_ids=tokenized_inputs["input_ids"], attention_mask=tokenized_inputs["attention_mask"], decoder_input_ids=decoder_input_ids, all_decoder_input_ids=list(all_decoder_input_ids), decoder_attention_mask=None, encoder_last_hidden_state=None, past_key_values=None, input_lengths=input_lengths.tolist(), decoder_input_lengths=decoder_input_lengths, offsets=offsets, token_offsets=token_offsets, next_token_choosers=next_token_choosers, stopping_criterias=stopping_criterias, max_input_length=max_input_length.item(), max_decoder_input_length=1, padding_right_offset=padding_right_offset, max_tokens=max_tokens, ) @tracer.start_as_current_span("filter") def filter( self, requests: List[generate_pb2.Request] ) -> Optional["Seq2SeqLMBatch"]: if len(requests) == 0: raise ValueError("Batch must have at least one request") if len(requests) == len(self): return self keep_indices = [] # New values after filtering requests_idx_mapping = {} input_lengths = [] decoder_input_lengths = [] offsets = [] token_offsets = [] all_decoder_input_ids = [] next_token_choosers = [] stopping_criterias = [] max_input_length = 0 max_decoder_input_length = 0 padding_right_offset = 0 total_remaining_decode_tokens = 0 for i, r in enumerate(requests): idx = self.requests_idx_mapping[r.id] requests_idx_mapping[r.id] = i keep_indices.append(idx) offsets.append(self.offsets[idx]) token_offsets.append(self.token_offsets[idx]) all_decoder_input_ids.append(self.all_decoder_input_ids[idx]) request_input_length = self.input_lengths[idx] input_lengths.append(request_input_length) max_input_length = max(max_input_length, request_input_length) request_decoder_input_length = self.decoder_input_lengths[idx] decoder_input_lengths.append(request_decoder_input_length) max_decoder_input_length = max( max_decoder_input_length, request_decoder_input_length ) next_token_choosers.append(self.next_token_choosers[idx]) stopping_criteria = self.stopping_criterias[idx] stopping_criterias.append(stopping_criteria) remaining_decode_tokens = ( stopping_criteria.max_new_tokens - stopping_criteria.current_tokens ) total_remaining_decode_tokens += remaining_decode_tokens padding_right_offset = max(padding_right_offset, remaining_decode_tokens) # Apply indices to input_ids, attention mask, past key values and other items that need to be cached self.decoder_input_ids = self.decoder_input_ids[keep_indices] self.attention_mask = self.attention_mask[keep_indices, -max_input_length:] if self.decoder_attention_mask is not None: self.decoder_attention_mask = self.decoder_attention_mask[ keep_indices, -(self.padding_right_offset + max_decoder_input_length) : ( self.decoder_attention_mask.shape[1] - self.padding_right_offset ) + padding_right_offset, ] self.encoder_last_hidden_state = self.encoder_last_hidden_state[ keep_indices, -max_input_length: ] # Ensure that past_key_values tensors can be updated in-place if type(self.past_key_values[0]) == tuple: self.past_key_values = [ [t for t in layer] for layer in self.past_key_values ] decoder_past_seq_len = max_decoder_input_length - 1 for layer in self.past_key_values: layer[0] = layer[0][keep_indices, :, -decoder_past_seq_len:] layer[1] = layer[1][keep_indices, :, -decoder_past_seq_len:] layer[2] = layer[2][keep_indices, :, -max_input_length:] layer[3] = layer[3][keep_indices, :, -max_input_length:] max_tokens = ( len(requests) * (max_input_length + max_decoder_input_length) + remaining_decode_tokens ) self.requests = requests self.requests_idx_mapping = requests_idx_mapping self.input_ids = None self.all_decoder_input_ids = all_decoder_input_ids self.input_lengths = input_lengths self.decoder_input_lengths = decoder_input_lengths self.offsets = offsets self.token_offsets = token_offsets self.next_token_choosers = next_token_choosers self.stopping_criterias = stopping_criterias self.max_input_length = max_input_length self.max_decoder_input_length = max_decoder_input_length self.padding_right_offset = padding_right_offset self.max_tokens = max_tokens return self @classmethod @tracer.start_as_current_span("concatenate") def concatenate(cls, batches: List["Seq2SeqLMBatch"]) -> "Seq2SeqLMBatch": """Concatenate multiple batches together by padding internal torch tensors""" # Used for padding total_batch_size = 0 max_input_length = 0 max_decoder_input_length = 0 padding_right_offset = 0 for batch in batches: total_batch_size += len(batch) max_input_length = max(max_input_length, batch.max_input_length) max_decoder_input_length = max( max_decoder_input_length, batch.max_decoder_input_length ) padding_right_offset = max(padding_right_offset, batch.padding_right_offset) # Batch attributes requests = [] requests_idx_mapping = {} all_decoder_input_ids = [] input_lengths = [] decoder_input_lengths = [] offsets = [] token_offsets = [] next_token_choosers = [] stopping_criterias = [] max_tokens = 0 # Batch tensors attention_mask = None decoder_input_ids = None decoder_attention_mask = None encoder_last_hidden_state = None past_key_values = [] # Used for slicing correctly inside the tensors # Equivalent to a cumsum on batch sizes start_index = 0 for i, batch in enumerate(batches): # Extend all list attributes requests.extend(batch.requests) all_decoder_input_ids.extend(batch.all_decoder_input_ids) input_lengths.extend(batch.input_lengths) decoder_input_lengths.extend(batch.decoder_input_lengths) offsets.extend(batch.offsets) token_offsets.extend(batch.token_offsets) next_token_choosers.extend(batch.next_token_choosers) stopping_criterias.extend(batch.stopping_criterias) if i == 0: requests_idx_mapping = batch.requests_idx_mapping else: # We need to offset the mapping for each batch by the cumulative batch size for k, v in batch.requests_idx_mapping.items(): requests_idx_mapping[k] = v + start_index # Slicing end index for this batch end_index = start_index + len(batch) # We only concatenate batches that did at least one step if batch.encoder_last_hidden_state is None: raise ValueError("Batch encoder_last_hidden_state cannot be None") # Create padded tensor if attention_mask is None: attention_mask = batch.attention_mask.new_zeros( (total_batch_size, max_input_length), ) # Copy to correct indices attention_mask[ start_index:end_index, -batch.max_input_length : ] = batch.attention_mask[:, -batch.max_input_length :] # Create padded tensor if decoder_input_ids is None: decoder_input_ids = batch.decoder_input_ids.new_zeros( (total_batch_size, 1), ) # Copy to correct indices decoder_input_ids[start_index:end_index] = batch.decoder_input_ids # Create padded tensor if decoder_attention_mask is None: # As decoder_attention_mask might not exist, we use `batch.attention_mask` for device here decoder_attention_mask = batch.attention_mask.new_zeros( (total_batch_size, max_decoder_input_length + padding_right_offset), ) # If the decoder mask does not exist yet, all generations started at the same time and we never concatenated # this batch. All generations are of length `batch.max_decoder_input_length`. left_offset = max_decoder_input_length - batch.max_decoder_input_length if batch.decoder_attention_mask is None: decoder_attention_mask[ start_index:end_index, left_offset:-padding_right_offset, ] = 1 # If it exists, we need to index else: batch_left_offset = ( batch.decoder_attention_mask.shape[1] - batch.max_decoder_input_length - batch.padding_right_offset ) decoder_attention_mask[ start_index:end_index, left_offset:-padding_right_offset, ] = batch.decoder_attention_mask[ :, batch_left_offset : -batch.padding_right_offset, ] # Create padded tensor if encoder_last_hidden_state is None: encoder_last_hidden_state = batch.encoder_last_hidden_state.new_zeros( ( total_batch_size, max_input_length, batch.encoder_last_hidden_state.shape[-1], ), ) # Copy to correct indices encoder_last_hidden_state[ start_index:end_index, -batch.max_input_length :, : ] = batch.encoder_last_hidden_state[:, -batch.max_input_length :, :] batch.encoder_last_hidden_state = None # Ensure that we can update tensors in-place if type(batch.past_key_values[0]) == tuple: batch.past_key_values = [ [t for t in layer] for layer in batch.past_key_values ] # Add eventual padding tokens that were added while concatenating max_tokens += batch.max_tokens + ( max_input_length - batch.max_input_length + max_decoder_input_length - batch.max_decoder_input_length ) * len(batch) start_index = end_index # Determine shapes for new past kv tensors first_past_kvs = batches[0].past_key_values _, num_heads, _, head_dim = first_past_kvs[0][0].shape padded_dec_t_shape = ( total_batch_size, num_heads, (max_decoder_input_length - 1), head_dim, ) padded_enc_t_shape = ( total_batch_size, num_heads, max_input_length, head_dim, ) # Iterate over attention layers for j in range(len(first_past_kvs)): past_key_values.append([]) # Decoder past for k in range(0, 2): # Initialize tensors padded_past_values = first_past_kvs[j][k].new_zeros(padded_dec_t_shape) past_key_values[j].append(padded_past_values) start_index = 0 for batch in batches: t = batch.past_key_values[j][k] # Clear reference to the original tensor batch.past_key_values[j][k] = None # Slicing end index for this batch end_index = start_index + len(batch) # We slice the past keys and values to remove the padding from previous batches past_seq_len = batch.max_decoder_input_length - 1 padded_past_values[start_index:end_index, :, -past_seq_len:, :] = t[ :, :, -past_seq_len:, : ] del t start_index = end_index # Encoder past for k in range(2, 4): # Initialize tensors padded_past_values = first_past_kvs[j][k].new_zeros(padded_enc_t_shape) past_key_values[j].append(padded_past_values) start_index = 0 for batch in batches: t = batch.past_key_values[j][k] # Clear reference to the original tensor batch.past_key_values[j][k] = None # Slicing end index for this batch end_index = start_index + len(batch) # We slice the past keys and values to remove the padding from previous batches padded_past_values[ start_index:end_index, :, -batch.max_input_length :, : ] = t[:, :, -batch.max_input_length :, :] del t start_index = end_index return cls( batch_id=batches[0].batch_id, requests=requests, requests_idx_mapping=requests_idx_mapping, input_ids=None, attention_mask=attention_mask, decoder_input_ids=decoder_input_ids, all_decoder_input_ids=all_decoder_input_ids, decoder_attention_mask=decoder_attention_mask, encoder_last_hidden_state=encoder_last_hidden_state, past_key_values=past_key_values, input_lengths=input_lengths, decoder_input_lengths=decoder_input_lengths, offsets=offsets, token_offsets=token_offsets, next_token_choosers=next_token_choosers, stopping_criterias=stopping_criterias, max_input_length=max_input_length, max_decoder_input_length=max_decoder_input_length, padding_right_offset=padding_right_offset, max_tokens=max_tokens, ) def __len__(self): return len(self.requests) class Seq2SeqLM(Model): def __init__( self, model_id: str, revision: Optional[str] = None, quantize: Optional[str] = None, decode_buffer: int = 3, ): if torch.cuda.is_available(): device = torch.device("cuda") dtype = torch.float16 else: if quantize: raise ValueError("quantization is not available on CPU") device = torch.device("cpu") dtype = torch.float32 self.model = AutoModelForSeq2SeqLM.from_pretrained( model_id, revision=revision, torch_dtype=dtype, device_map="auto" if torch.cuda.is_available() else None, load_in_8bit=quantize == "bitsandbytes", ).eval() tokenizer = AutoTokenizer.from_pretrained( model_id, revision=revision, padding_side="left", truncation_side="left" ) tokenizer.bos_token_id = self.model.config.decoder_start_token_id super(Seq2SeqLM, self).__init__( tokenizer=tokenizer, requires_padding=True, dtype=dtype, device=device, decode_buffer=decode_buffer, ) @property def batch_type(self) -> Type[Seq2SeqLMBatch]: return Seq2SeqLMBatch def decode(self, decoder_ids: List[int]) -> str: return self.tokenizer.decode( decoder_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False ) def forward( self, input_ids, attention_mask, decoder_input_ids, decoder_attention_mask: Optional, encoder_last_hidden_state: Optional, past_key_values: Optional = None, ) -> Tuple[ torch.Tensor, torch.Tensor, List[Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]], ]: # Model Forward outputs = self.model.forward( input_ids=input_ids, attention_mask=attention_mask, decoder_input_ids=decoder_input_ids, decoder_attention_mask=decoder_attention_mask, encoder_outputs=encoder_last_hidden_state, past_key_values=past_key_values, use_cache=True, ) return ( outputs.logits, outputs.encoder_last_hidden_state, outputs.past_key_values, ) @tracer.start_as_current_span("generate_token") def generate_token( self, batch: Seq2SeqLMBatch ) -> Tuple[List[Generation], Optional[Seq2SeqLMBatch]]: if batch.decoder_attention_mask is not None: # slice to the correct shape decoder_attention_mask = batch.decoder_attention_mask[ :, : -batch.padding_right_offset ] else: decoder_attention_mask = None # Wrap `encoder_last_hidden_state` because for some reason, Transformers does a `encoder_last_hidden_state[0]` # internally... if batch.encoder_last_hidden_state is not None: encoder_last_hidden_state = [batch.encoder_last_hidden_state] else: encoder_last_hidden_state = None logits, encoder_last_hidden_state, past = self.forward( batch.input_ids, batch.attention_mask, batch.decoder_input_ids, decoder_attention_mask, encoder_last_hidden_state, batch.past_key_values, ) # Finished requests generations: List[Generation] = [] stopped = True # Zipped iterator iterator = zip( batch.requests, batch.input_lengths, batch.offsets, batch.token_offsets, batch.decoder_input_lengths, logits, batch.next_token_choosers, batch.stopping_criterias, batch.all_decoder_input_ids, ) # For each member of the batch for i, ( request, input_length, offset, token_offset, decoder_input_length, logits, next_token_chooser, stopping_criteria, all_decoder_input_ids, ) in enumerate(iterator): # Select next token next_token_id, logprobs = next_token_chooser( all_decoder_input_ids.view(1, -1), logits[-1:, :] ) # Append next token to decoder tokens all_decoder_input_ids = torch.cat( [all_decoder_input_ids, next_token_id.squeeze(1)] ) new_decoder_input_length = decoder_input_length + 1 # Generated token next_token_logprob = logprobs[-1, next_token_id] next_token_id_squeezed = next_token_id.squeeze() next_token_text, offset, token_offset = self.decode_token( all_decoder_input_ids, offset, token_offset ) # Evaluate stopping criteria stop, reason = stopping_criteria(next_token_id, next_token_text) if not stop: stopped = False # Shard generations # All generations will be appended in the rust sharded client if i % self.world_size == self.rank: if stop: # Slice with decoder_input_length to remove padding # Decode all tokens output_text = self.decode( all_decoder_input_ids[-decoder_input_length:] ) # Get seed if isinstance(next_token_chooser.choice, Sampling): seed = next_token_chooser.choice.seed else: seed = None generated_text = GeneratedText( output_text, stopping_criteria.current_tokens, reason, seed ) else: generated_text = None # Prefill if stopping_criteria.current_tokens == 1: prefill_tokens = PrefillTokens( [self.tokenizer.bos_token_id], [float("nan")], [self.tokenizer.bos_token], ) else: prefill_tokens = None generation = Generation( request.id, prefill_tokens, next_token_id_squeezed, next_token_logprob, next_token_text, next_token_id_squeezed.item() in self.all_special_ids, generated_text, ) generations.append(generation) # Update values batch.decoder_input_ids[i] = next_token_id batch.all_decoder_input_ids[i] = all_decoder_input_ids batch.input_lengths[i] = input_length batch.decoder_input_lengths[i] = new_decoder_input_length batch.offsets[i] = offset batch.token_offsets[i] = token_offset batch.max_input_length = max(batch.max_input_length, input_length) batch.max_decoder_input_length = max( batch.max_decoder_input_length, new_decoder_input_length ) # We finished all generations in the batch; there is no next batch if stopped: return generations, None # We don't need input_ids after the prefill forward batch.input_ids = None batch.encoder_last_hidden_state = encoder_last_hidden_state batch.past_key_values = past # Update decoder_attention_mask as we added a new token to input_ids if batch.decoder_attention_mask is not None: batch.decoder_attention_mask[:, -batch.padding_right_offset] = 1 batch.padding_right_offset -= 1 return generations, batch