hf_text-generation-inference/server/text_generation_server/models/seq2seq_lm.py

840 lines
31 KiB
Python

import torch
import time
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.utils.tokens import batch_top_tokens
from text_generation_server.models import Model
from text_generation_server.models.types import (
GeneratedText,
Batch,
Generation,
Tokens,
)
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]
prefix_offsets: List[int]
read_offsets: List[int]
# Generation helpers
next_token_choosers: List[NextTokenChooser]
stopping_criterias: List[StoppingCriteria]
top_n_tokens: List[int]
top_n_tokens_tensor: torch.Tensor
# 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.CachedBatch:
"""Convert a Seq2SeqLMBatch to a text_generation_server.v1.CachedBatch protobuf"""
return generate_pb2.CachedBatch(
id=self.batch_id,
request_ids=[r.id for r in self.requests],
size=len(self),
max_tokens=self.max_tokens,
)
@classmethod
def from_pb(
cls,
pb: generate_pb2.Batch,
tokenizer: PreTrainedTokenizerBase,
dtype: torch.dtype,
device: torch.device,
) -> "Seq2SeqLMBatch":
"""Convert a text_generation_server.v1.Batch protobuf to a Seq2SeqLMBatch"""
inputs = []
next_token_choosers = []
stopping_criterias = []
top_n_tokens = []
decoder_input_lengths = []
prefix_offsets = []
read_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)
next_token_choosers.append(
NextTokenChooser.from_pb(r.parameters, device, tokenizer)
)
stopping_criteria = StoppingCriteria.from_pb(
r.stopping_parameters, tokenizer
)
stopping_criterias.append(stopping_criteria)
top_n_tokens.append(r.top_n_tokens)
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)
)
for _ in pb.requests:
prefix_offsets.append(0)
read_offsets.append(1)
all_decoder_input_ids = decoder_input_ids.view(-1).split(1)
top_n_tokens_tensor = torch.tensor(
top_n_tokens, device=device, dtype=torch.int64
)
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,
prefix_offsets=prefix_offsets,
read_offsets=read_offsets,
next_token_choosers=next_token_choosers,
stopping_criterias=stopping_criterias,
top_n_tokens=top_n_tokens,
top_n_tokens_tensor=top_n_tokens_tensor,
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, request_ids: List[int]) -> Optional["Seq2SeqLMBatch"]:
if len(request_ids) == 0:
raise ValueError("Batch must have at least one request")
if len(request_ids) == len(self):
return self
keep_indices = []
# New values after filtering
requests_idx_mapping = {}
requests = []
input_lengths = []
decoder_input_lengths = []
prefix_offsets = []
read_offsets = []
all_decoder_input_ids = []
next_token_choosers = []
stopping_criterias = []
top_n_tokens = []
max_input_length = 0
max_decoder_input_length = 0
padding_right_offset = 0
total_remaining_decode_tokens = 0
for i, request_id in enumerate(request_ids):
idx = self.requests_idx_mapping[request_id]
requests_idx_mapping[request_id] = i
keep_indices.append(idx)
requests.append(self.requests[idx])
prefix_offsets.append(self.prefix_offsets[idx])
read_offsets.append(self.read_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)
top_n_tokens.append(self.top_n_tokens[idx])
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:]
top_n_tokens_tensor = self.top_n_tokens_tensor[keep_indices]
max_tokens = (
len(request_ids) * (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.prefix_offsets = prefix_offsets
self.read_offsets = read_offsets
self.next_token_choosers = next_token_choosers
self.stopping_criterias = stopping_criterias
self.top_n_tokens = top_n_tokens
self.top_n_tokens_tensor = top_n_tokens_tensor
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 = []
prefix_offsets = []
read_offsets = []
next_token_choosers = []
stopping_criterias = []
top_n_tokens = []
max_tokens = 0
# Batch tensors
attention_mask = None
decoder_input_ids = None
decoder_attention_mask = None
encoder_last_hidden_state = None
top_n_tokens_tensor = 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)
prefix_offsets.extend(batch.prefix_offsets)
read_offsets.extend(batch.read_offsets)
next_token_choosers.extend(batch.next_token_choosers)
stopping_criterias.extend(batch.stopping_criterias)
top_n_tokens.extend(batch.top_n_tokens)
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],
),
)
if top_n_tokens_tensor is None:
top_n_tokens_tensor = batches[0].top_n_tokens_tensor.new_zeros(
total_batch_size,
)
top_n_tokens_tensor[start_index:end_index] = batch.top_n_tokens_tensor
# 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,
prefix_offsets=prefix_offsets,
read_offsets=read_offsets,
next_token_choosers=next_token_choosers,
stopping_criterias=stopping_criterias,
top_n_tokens=top_n_tokens,
top_n_tokens_tensor=top_n_tokens_tensor,
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,
use_medusa: Optional[str] = None,
dtype: Optional[torch.dtype] = None,
trust_remote_code: bool = False,
):
if use_medusa:
raise RuntimeError("Medusa decoding is not enabled for AutoModel")
if torch.cuda.is_available():
device = torch.device("cuda")
dtype = torch.float16 if dtype is None else dtype
else:
if quantize:
raise ValueError("quantization is not available on CPU")
device = torch.device("cpu")
dtype = torch.float32 if dtype is None else dtype
model = AutoModelForSeq2SeqLM.from_pretrained(
model_id,
revision=revision,
torch_dtype=dtype,
device_map=(
"auto"
if torch.cuda.is_available() and torch.cuda.device_count() > 1
else None
),
load_in_8bit=quantize == "bitsandbytes",
trust_remote_code=trust_remote_code,
)
if torch.cuda.is_available() and torch.cuda.device_count() == 1:
model = model.cuda()
tokenizer = AutoTokenizer.from_pretrained(
model_id,
revision=revision,
padding_side="left",
truncation_side="left",
trust_remote_code=trust_remote_code,
)
tokenizer.bos_token_id = model.config.decoder_start_token_id
super(Seq2SeqLM, self).__init__(
model=model,
tokenizer=tokenizer,
requires_padding=True,
dtype=dtype,
device=device,
)
@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,
Optional[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,
)
if isinstance(outputs, tuple):
# Our custom models
outputs, speculative_logits = outputs
else:
# Generic transformers models
speculative_logits = None
return (
outputs.logits,
speculative_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], Tuple[int, int]]:
start = time.time_ns()
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, speculative_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,
)
# Speculation is not active for seq2seq
accepted_ids = torch.ones_like(batch.decoder_input_ids)[:, 0]
batch_top_token_ids, batch_top_token_logprobs = batch_top_tokens(
batch.top_n_tokens,
batch.top_n_tokens_tensor,
torch.log_softmax(logits[:, -1], -1),
accepted_ids,
)
start_decode = time.time_ns()
# Finished requests
generations: List[Generation] = []
stopped = True
# Zipped iterator
iterator = zip(
batch.requests,
batch.input_lengths,
batch.prefix_offsets,
batch.read_offsets,
batch.decoder_input_lengths,
logits,
batch.next_token_choosers,
batch.stopping_criterias,
batch.all_decoder_input_ids,
batch.top_n_tokens,
batch_top_token_ids,
batch_top_token_logprobs,
)
# For each member of the batch
for i, (
request,
input_length,
prefix_offset,
read_offset,
decoder_input_length,
logits,
next_token_chooser,
stopping_criteria,
all_decoder_input_ids,
top_n_tokens,
top_token_ids,
top_token_logprobs,
) 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, prefix_offset, read_offset = self.decode_token(
all_decoder_input_ids, prefix_offset, read_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_token(
all_decoder_input_ids,
prefix_offset=len(all_decoder_input_ids)
- decoder_input_length
- 1,
read_offset=len(all_decoder_input_ids) - decoder_input_length,
skip_special_tokens=True,
)
# 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 and request.prefill_logprobs:
prefill_tokens = Tokens(
[self.tokenizer.bos_token_id],
[float("nan")],
[self.tokenizer.bos_token],
[False],
)
else:
prefill_tokens = None
if top_n_tokens > 0:
all_top_tokens = []
for top_token_ids, top_token_logprobs in zip(
top_token_ids, top_token_logprobs
):
toptoken_texts = self.tokenizer.batch_decode(
top_token_ids,
clean_up_tokenization_spaces=False,
skip_special_tokens=False,
)
special_toptokens = [
token_id in self.all_special_ids
for token_id in top_token_ids
]
top_tokens = Tokens(
top_token_ids,
top_token_logprobs,
toptoken_texts,
special_toptokens,
)
all_top_tokens.append(top_tokens)
top_tokens = all_top_tokens
else:
top_tokens = None
generation = Generation(
request.id,
prefill_tokens,
Tokens(
[next_token_id_squeezed],
[next_token_logprob],
[next_token_text],
[next_token_id_squeezed.item() in self.all_special_ids],
),
generated_text,
top_tokens,
)
generations.append(generation)
# Update values
batch.next_token_choosers[i] = batch.next_token_choosers[i].advance_grammar(
next_token_id_squeezed.item()
)
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.prefix_offsets[i] = prefix_offset
batch.read_offsets[i] = read_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:
forward_ns = start_decode - start
decode_ns = time.time_ns() - start_decode
return generations, None, (forward_ns, decode_ns)
# 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
forward_ns = start_decode - start
decode_ns = time.time_ns() - start_decode
return generations, batch, (forward_ns, decode_ns)