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ColossalAI/colossalai/shardformer/modeling/t5.py

794 lines
37 KiB

import warnings
from typing import Dict, List, Optional, Tuple, Union
import torch
from torch.nn import CrossEntropyLoss
from torch.utils.checkpoint import checkpoint
from transformers.modeling_outputs import (
BaseModelOutput,
BaseModelOutputWithPastAndCrossAttentions,
Seq2SeqLMOutput,
Seq2SeqModelOutput,
)
from transformers.models.t5.modeling_t5 import T5EncoderModel, T5ForConditionalGeneration, T5Model, T5Stack
from transformers.utils import logging
from colossalai.pipeline.stage_manager import PipelineStageManager
class T5PipelineForwards:
"""
This class serves as a micro library for forward function substitution of
T5 models under pipeline setting.
"""
@staticmethod
def t5_stack_forward(
self: T5Stack,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
encoder_hidden_states: Optional[torch.Tensor] = None,
encoder_attention_mask: Optional[torch.FloatTensor] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
head_mask: Optional[torch.FloatTensor] = None,
cross_attn_head_mask: Optional[torch.Tensor] = None,
past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None,
use_cache: Optional[bool] = False,
output_attentions: Optional[bool] = False,
output_hidden_states: Optional[bool] = False,
return_dict: Optional[bool] = None,
stage_manager: Optional[PipelineStageManager] = None,
hidden_states: Optional[torch.FloatTensor] = None,
position_bias: Optional[torch.Tensor] = None,
encoder_decoder_position_bias: Optional[torch.Tensor] = None,
stage_index: Optional[List[int]] = None,
decoder_starting_stage: Optional[int] = None,
) -> Union[Dict, Tuple, BaseModelOutputWithPastAndCrossAttentions]:
# This function is modified on the basis of transformers.models.t5.modeling_t5.T5Stack.forward.
# Please refer to original code of transformers for more details.
logger = logging.get_logger(__name__)
# TODO(baizhou): left the recording kv-value tensors as () or None type, this feature may be added in the future.
if past_key_values:
logger.warning_once("Non-empty past_key_values is not supported for pipeline models at the moment.")
past_key_values = None
if output_attentions:
logger.warning_once("output_attentions=True is not supported for pipeline models at the moment.")
output_attentions = False
if output_hidden_states:
logger.warning_once("output_hidden_states=True is not supported for pipeline models at the moment.")
output_hidden_states = False
if use_cache:
logger.warning_once("use_cache=True is not supported for pipeline models at the moment.")
use_cache = False
if use_cache is True:
if not in_decoder:
raise ValueError(f"`use_cache` can only be set to `True` if {self} is used as a decoder")
if self.gradient_checkpointing and self.training:
if use_cache:
logger.warning_once(
"`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`..."
)
use_cache = False
stage = stage_manager.stage
in_decoder = self.is_decoder
if in_decoder != (stage >= decoder_starting_stage):
raise ValueError("Config in T5Stack is not aligned with pipeline setting.")
# at_first_stage: current stage is the first stage of encoder/decoder, taking input_ids/input_embedds
# at_last_stage: current stage is the last stage of encoder/decoder, making outputs the same form as huggingface
at_first_stage = (stage == 0) or (stage == decoder_starting_stage)
at_last_stage = (stage == decoder_starting_stage - 1) or (stage == stage_manager.num_stages - 1)
# Process inputs if at the first stage of encoder/decoder.
if at_first_stage:
if input_ids is not None and inputs_embeds is not None:
err_msg_prefix = "decoder_" if in_decoder else ""
raise ValueError(
f"You cannot specify both {err_msg_prefix}input_ids and {err_msg_prefix}inputs_embeds at the same time"
)
elif input_ids is not None:
input_shape = input_ids.size()
input_ids = input_ids.view(-1, input_shape[-1])
elif inputs_embeds is not None:
input_shape = inputs_embeds.size()[:-1]
else:
err_msg_prefix = "decoder_" if in_decoder else ""
raise ValueError(
f"You have to specify either {err_msg_prefix}input_ids or {err_msg_prefix}inputs_embeds"
)
if inputs_embeds is None:
if self.embed_tokens is None:
raise ValueError("You have to initialize the model with valid token embeddings")
inputs_embeds = self.embed_tokens(input_ids)
batch_size, seq_length = input_shape
device = inputs_embeds.device
hidden_states = self.dropout(inputs_embeds)
else:
if hidden_states is None:
raise ValueError(
"hidden_states shouldn't be None for stages other than the first stage of encoder/decoder."
)
input_shape = hidden_states.size()[:-1]
batch_size, seq_length = input_shape[0], input_shape[1]
device = hidden_states.device
# required mask seq length can be calculated via length of past
mask_seq_length = past_key_values[0][0].shape[2] + seq_length if past_key_values is not None else seq_length
if attention_mask is None:
attention_mask = torch.ones(batch_size, mask_seq_length, device=device)
if in_decoder and encoder_attention_mask is None and encoder_hidden_states is not None:
encoder_seq_length = encoder_hidden_states.shape[1]
encoder_attention_mask = torch.ones(batch_size, encoder_seq_length, device=device, dtype=torch.long)
# initialize past_key_values with `None` if past does not exist
if past_key_values is None:
past_key_values = [None] * len(self.block)
# We can provide a self-attention mask of dimensions [batch_size, from_seq_length, to_seq_length]
# ourselves in which case we just need to make it broadcastable to all heads.
extended_attention_mask = self.get_extended_attention_mask(attention_mask, input_shape)
# If a 2D or 3D attention mask is provided for the cross-attention
# we need to make broadcastable to [batch_size, num_heads, seq_length, seq_length]
if self.is_decoder and encoder_hidden_states is not None:
encoder_batch_size, encoder_sequence_length, _ = encoder_hidden_states.size()
encoder_hidden_shape = (encoder_batch_size, encoder_sequence_length)
if encoder_attention_mask is None:
encoder_attention_mask = torch.ones(encoder_hidden_shape, device=inputs_embeds.device)
encoder_extended_attention_mask = self.invert_attention_mask(encoder_attention_mask)
else:
encoder_extended_attention_mask = None
# Prepare head mask if needed
head_mask = self.get_head_mask(head_mask, self.config.num_layers)
cross_attn_head_mask = self.get_head_mask(cross_attn_head_mask, self.config.num_layers)
present_key_value_states = () if use_cache else None
all_hidden_states = () if output_hidden_states else None
all_attentions = () if output_attentions else None
all_cross_attentions = () if (output_attentions and self.is_decoder) else None
# Going through held blocks.
start_idx, end_idx = stage_index[0], stage_index[1]
for i in range(start_idx, end_idx):
past_key_value = past_key_values[i]
layer_module = self.block[i]
layer_head_mask = head_mask[i]
cross_attn_layer_head_mask = cross_attn_head_mask[i]
torch.cuda.set_device(hidden_states.device)
if self.gradient_checkpointing and self.training:
def create_custom_forward(module):
def custom_forward(*inputs):
return tuple(module(*inputs, use_cache, output_attentions))
return custom_forward
layer_outputs = checkpoint(
create_custom_forward(layer_module),
hidden_states,
extended_attention_mask,
position_bias,
encoder_hidden_states,
encoder_extended_attention_mask,
encoder_decoder_position_bias,
layer_head_mask,
cross_attn_layer_head_mask,
None, # past_key_value is always None with gradient checkpointing
)
else:
layer_outputs = layer_module(
hidden_states,
attention_mask=extended_attention_mask,
position_bias=position_bias,
encoder_hidden_states=encoder_hidden_states,
encoder_attention_mask=encoder_extended_attention_mask,
encoder_decoder_position_bias=encoder_decoder_position_bias,
layer_head_mask=layer_head_mask,
cross_attn_layer_head_mask=cross_attn_layer_head_mask,
past_key_value=past_key_value,
use_cache=use_cache,
output_attentions=output_attentions,
)
# layer_outputs is a tuple with:
# hidden-states, key-value-states, (self-attention position bias), (self-attention weights), (cross-attention position bias), (cross-attention weights)
if use_cache is False or use_cache is None:
layer_outputs = layer_outputs[:1] + (None,) + layer_outputs[1:]
hidden_states, present_key_value_state = layer_outputs[:2]
# We share the position biases between the layers - the first layer store them
# layer_outputs = hidden-states, key-value-states (self-attention position bias), (self-attention weights),
# (cross-attention position bias), (cross-attention weights)
position_bias = layer_outputs[2]
if in_decoder and encoder_hidden_states is not None:
encoder_decoder_position_bias = layer_outputs[4 if output_attentions else 3]
# append next layer key value states
if use_cache:
present_key_value_states = present_key_value_states + (present_key_value_state,)
# last layer
if at_last_stage:
hidden_states = self.final_layer_norm(hidden_states)
hidden_states = self.dropout(hidden_states)
if not return_dict:
return tuple(
v
for v in [
hidden_states,
present_key_value_states,
all_hidden_states,
all_attentions,
all_cross_attentions,
]
if v is not None
)
return BaseModelOutputWithPastAndCrossAttentions(
last_hidden_state=hidden_states,
past_key_values=present_key_value_states,
hidden_states=all_hidden_states,
attentions=all_attentions,
cross_attentions=all_cross_attentions,
)
else:
return {
"hidden_states": hidden_states,
"position_bias": position_bias,
"encoder_decoder_position_bias": encoder_decoder_position_bias,
"backward_tensor_keys": ["hidden_states"],
}
@staticmethod
def t5_model_forward(
self: T5Model,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
decoder_input_ids: Optional[torch.LongTensor] = None,
decoder_attention_mask: Optional[torch.BoolTensor] = None,
head_mask: Optional[torch.FloatTensor] = None,
decoder_head_mask: Optional[torch.FloatTensor] = None,
cross_attn_head_mask: Optional[torch.Tensor] = None,
encoder_outputs: Optional[Tuple[Tuple[torch.FloatTensor]]] = None,
past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None,
inputs_embeds: Optional[torch.Tensor] = None,
decoder_inputs_embeds: Optional[torch.Tensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
stage_manager: Optional[PipelineStageManager] = None,
hidden_states: Optional[torch.FloatTensor] = None,
encoder_hidden_states: Optional[torch.FloatTensor] = None,
position_bias: Optional[torch.Tensor] = None,
encoder_decoder_position_bias: Optional[torch.Tensor] = None,
backward_tensor_keys: Optional[List[str]] = None,
stage_index: Optional[List[int]] = None,
decoder_starting_stage: Optional[int] = None,
) -> Union[Tuple[torch.FloatTensor], Seq2SeqModelOutput]:
# This function is modified on the basis of transformers.models.t5.modeling_t5.T5Model.forward.
# Please refer to original code of transformers for more details.
__HEAD_MASK_WARNING_MSG = """
The input argument `head_mask` was split into two arguments `head_mask` and `decoder_head_mask`. Currently,
`decoder_head_mask` is set to copy `head_mask`, but this feature is deprecated and will be removed in future versions.
If you do not want to use any `decoder_head_mask` now, please set `decoder_head_mask = torch.ones(num_layers,
num_heads)`.
"""
use_cache = use_cache if use_cache is not None else self.config.use_cache
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
logger = logging.get_logger(__name__)
# TODO(baizhou): left the recording kv-value tensors as () or None type, this feature may be added in the future.
if past_key_values:
logger.warning_once("Non-empty past_key_values is not supported for pipeline models at the moment.")
past_key_values = None
if output_attentions:
logger.warning_once("output_attentions=True is not supported for pipeline models at the moment.")
output_attentions = False
if output_hidden_states:
logger.warning_once("output_hidden_states=True is not supported for pipeline models at the moment.")
output_hidden_states = False
if use_cache:
logger.warning_once("use_cache=True is not supported for pipeline models at the moment.")
use_cache = False
# FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask
if head_mask is not None and decoder_head_mask is None:
if self.config.num_layers == self.config.num_decoder_layers:
warnings.warn(__HEAD_MASK_WARNING_MSG, FutureWarning)
decoder_head_mask = head_mask
in_decoder = stage_manager.stage >= decoder_starting_stage
# Stage is in encoder, directly return the output of t5_stack_forward
if not in_decoder:
encoder_outputs = T5PipelineForwards.t5_stack_forward(
self.encoder,
input_ids=input_ids,
attention_mask=attention_mask,
inputs_embeds=inputs_embeds,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
stage_manager=stage_manager,
hidden_states=hidden_states,
position_bias=position_bias,
encoder_decoder_position_bias=encoder_decoder_position_bias,
stage_index=stage_index,
decoder_starting_stage=decoder_starting_stage,
)
if stage_manager.stage == decoder_starting_stage - 1:
# last stage of encoder
return {"encoder_hidden_states": encoder_outputs[0]}
else:
return encoder_outputs
at_last_decoder_stage = stage_manager.is_last_stage()
at_first_decoder_stage = stage_manager.stage == decoder_starting_stage
if encoder_outputs is not None:
encoder_hidden_states = encoder_outputs[0]
elif encoder_hidden_states is None:
raise ValueError("Non-empty encoder_hidden_states should be passed in at decoder stages.")
if not at_first_decoder_stage and hidden_states is None:
raise ValueError("If not at the first layer of decoder, non-empty hidden_states must be provided.")
# Decode
decoder_outputs = T5PipelineForwards.t5_stack_forward(
self.decoder,
input_ids=decoder_input_ids,
attention_mask=decoder_attention_mask,
inputs_embeds=decoder_inputs_embeds,
past_key_values=past_key_values,
encoder_hidden_states=encoder_hidden_states,
encoder_attention_mask=attention_mask,
head_mask=decoder_head_mask,
cross_attn_head_mask=cross_attn_head_mask,
use_cache=use_cache,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
stage_manager=stage_manager,
hidden_states=hidden_states,
position_bias=position_bias,
encoder_decoder_position_bias=encoder_decoder_position_bias,
stage_index=stage_index,
decoder_starting_stage=decoder_starting_stage,
)
# Directly return outputs of overloaded T5Stack forward if not at last stage.
if not at_last_decoder_stage:
# encoder_hidden_states should be passed to the next stage
decoder_outputs["encoder_hidden_states"] = encoder_hidden_states
return decoder_outputs
if not return_dict:
return decoder_outputs + encoder_hidden_states
else:
return Seq2SeqModelOutput(
last_hidden_state=decoder_outputs.last_hidden_state,
past_key_values=decoder_outputs.past_key_values,
decoder_hidden_states=decoder_outputs.hidden_states,
decoder_attentions=decoder_outputs.attentions,
cross_attentions=decoder_outputs.cross_attentions,
encoder_last_hidden_state=encoder_hidden_states,
)
@staticmethod
def t5_for_conditional_generation_forward(
self: T5ForConditionalGeneration,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
decoder_input_ids: Optional[torch.LongTensor] = None,
decoder_attention_mask: Optional[torch.BoolTensor] = None,
head_mask: Optional[torch.FloatTensor] = None,
decoder_head_mask: Optional[torch.FloatTensor] = None,
cross_attn_head_mask: Optional[torch.Tensor] = None,
encoder_outputs: Optional[Tuple[Tuple[torch.Tensor]]] = None,
past_key_values: Optional[Tuple[Tuple[torch.Tensor]]] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
decoder_inputs_embeds: Optional[torch.FloatTensor] = None,
labels: Optional[torch.LongTensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
stage_manager: Optional[PipelineStageManager] = None,
hidden_states: Optional[torch.FloatTensor] = None,
encoder_hidden_states: Optional[torch.FloatTensor] = None,
position_bias: Optional[torch.Tensor] = None,
encoder_decoder_position_bias: Optional[torch.Tensor] = None,
backward_tensor_keys: Optional[List[str]] = None,
stage_index: Optional[List[int]] = None,
decoder_starting_stage: Optional[int] = None,
) -> Union[Tuple[torch.FloatTensor], Seq2SeqLMOutput]:
# This function is modified on the basis of transformers.models.t5.modeling_t5.T5ForConditionalGeneration.forward.
# Please refer to original code of transformers for more details.
__HEAD_MASK_WARNING_MSG = """
The input argument `head_mask` was split into two arguments `head_mask` and `decoder_head_mask`. Currently,
`decoder_head_mask` is set to copy `head_mask`, but this feature is deprecated and will be removed in future versions.
If you do not want to use any `decoder_head_mask` now, please set `decoder_head_mask = torch.ones(num_layers,
num_heads)`.
"""
use_cache = use_cache if use_cache is not None else self.config.use_cache
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
logger = logging.get_logger(__name__)
# TODO(baizhou): left the recording kv-value tensors as () or None type, this feature may be added in the future.
if past_key_values:
logger.warning_once("Non-empty past_key_values is not supported for pipeline models at the moment.")
past_key_values = None
if output_attentions:
logger.warning_once("output_attentions=True is not supported for pipeline models at the moment.")
output_attentions = False
if output_hidden_states:
logger.warning_once("output_hidden_states=True is not supported for pipeline models at the moment.")
output_hidden_states = False
if use_cache:
logger.warning_once("use_cache=True is not supported for pipeline models at the moment.")
use_cache = False
# FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask
if head_mask is not None and decoder_head_mask is None:
if self.config.num_layers == self.config.num_decoder_layers:
warnings.warn(__HEAD_MASK_WARNING_MSG, FutureWarning)
decoder_head_mask = head_mask
in_decoder = stage_manager.stage >= decoder_starting_stage
# Stage is in encoder, directly return the output of t5_stack_forward
if not in_decoder:
encoder_outputs = T5PipelineForwards.t5_stack_forward(
self.encoder,
input_ids=input_ids,
attention_mask=attention_mask,
inputs_embeds=inputs_embeds,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
stage_manager=stage_manager,
hidden_states=hidden_states,
position_bias=position_bias,
encoder_decoder_position_bias=encoder_decoder_position_bias,
stage_index=stage_index,
decoder_starting_stage=decoder_starting_stage,
)
if stage_manager.stage == decoder_starting_stage - 1:
# last stage of encoder
return {"encoder_hidden_states": encoder_outputs[0]}
else:
return encoder_outputs
at_last_decoder_stage = stage_manager.is_last_stage()
at_first_decoder_stage = stage_manager.stage == decoder_starting_stage
if encoder_outputs is not None:
encoder_hidden_states = encoder_outputs[0]
elif encoder_hidden_states is None:
raise ValueError("Non-empty encoder_hidden_states should be passed in at decoder stages.")
if not at_first_decoder_stage and hidden_states is None:
raise ValueError("If not at the first layer of decoder, non-empty hidden_states must be provided.")
if labels is not None and decoder_input_ids is None and decoder_inputs_embeds is None:
# get decoder inputs from shifting lm labels to the right
decoder_input_ids = self._shift_right(labels)
# Decode
decoder_outputs = T5PipelineForwards.t5_stack_forward(
self.decoder,
input_ids=decoder_input_ids,
attention_mask=decoder_attention_mask,
inputs_embeds=decoder_inputs_embeds,
past_key_values=past_key_values,
encoder_hidden_states=encoder_hidden_states,
encoder_attention_mask=attention_mask,
head_mask=decoder_head_mask,
cross_attn_head_mask=cross_attn_head_mask,
use_cache=use_cache,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
stage_manager=stage_manager,
hidden_states=hidden_states,
position_bias=position_bias,
encoder_decoder_position_bias=encoder_decoder_position_bias,
stage_index=stage_index,
decoder_starting_stage=decoder_starting_stage,
)
# Directly return outputs of overloaded T5Stack forward if not at last stage.
if not at_last_decoder_stage:
# encoder_hidden_states should be passed to the next stage
decoder_outputs["encoder_hidden_states"] = encoder_hidden_states
return decoder_outputs
sequence_output = decoder_outputs[0]
if self.config.tie_word_embeddings:
# Rescale output before projecting on vocab
# See https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/transformer/transformer.py#L586
sequence_output = sequence_output * (self.model_dim**-0.5)
lm_logits = self.lm_head(sequence_output)
loss = None
if labels is not None:
loss_fct = CrossEntropyLoss(ignore_index=-100)
# move labels to correct device to enable PP
labels = labels.to(lm_logits.device)
loss = loss_fct(lm_logits.view(-1, lm_logits.size(-1)), labels.view(-1))
if not return_dict:
output = (lm_logits,) + decoder_outputs[1:] + encoder_hidden_states
return ((loss,) + output) if loss is not None else output
return Seq2SeqLMOutput(
loss=loss,
logits=lm_logits,
past_key_values=decoder_outputs.past_key_values,
decoder_hidden_states=decoder_outputs.hidden_states,
decoder_attentions=decoder_outputs.attentions,
cross_attentions=decoder_outputs.cross_attentions,
encoder_last_hidden_state=encoder_hidden_states,
)
@staticmethod
def t5_encoder_model_forward(
self: T5EncoderModel,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
head_mask: Optional[torch.FloatTensor] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
stage_manager: Optional[PipelineStageManager] = None,
hidden_states: Optional[torch.FloatTensor] = None,
position_bias: Optional[torch.Tensor] = None,
encoder_decoder_position_bias: Optional[torch.Tensor] = None,
backward_tensor_keys: Optional[List[str]] = None,
stage_index: Optional[List[int]] = None,
decoder_starting_stage: Optional[int] = None,
) -> Union[Tuple[torch.FloatTensor], BaseModelOutput]:
r"""
This function is modified on the basis of transformers.models.t5.modeling_gpt2.T5EncoderModel.forward.
Please refer to original code of transformers for more details.
```"""
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
outputs = T5PipelineForwards.t5_stack_forward(
self.encoder,
input_ids=input_ids,
attention_mask=attention_mask,
inputs_embeds=inputs_embeds,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
stage_manager=stage_manager,
hidden_states=hidden_states,
position_bias=position_bias,
encoder_decoder_position_bias=encoder_decoder_position_bias,
stage_index=stage_index,
decoder_starting_stage=decoder_starting_stage,
)
return outputs
def get_t5_flash_attention_forward():
try:
from xformers.ops import memory_efficient_attention as me_attention
except:
raise ImportError("Error: xformers module is not installed. Please install it to use flash attention.")
from transformers.models.t5.modeling_t5 import T5Attention
def forward(
self: T5Attention,
hidden_states: torch.Tensor,
mask: Optional[torch.Tensor] = None,
key_value_states: Optional[torch.Tensor] = None,
position_bias: Optional[torch.Tensor] = None,
past_key_value: Optional[Tuple[torch.Tensor]] = None,
layer_head_mask: Optional[torch.Tensor] = None,
query_length: Optional[int] = None,
use_cache: bool = False,
output_attentions: bool = False,
) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[torch.Tensor]]:
"""
Self-attention (if key_value_states is None) or attention over source sentence (provided by key_value_states).
"""
# Input is (batch_size, seq_length, dim)
# Mask is (batch_size, key_length) (non-causal) or (batch_size, key_length, key_length)
# past_key_value[0] is (batch_size, n_heads, q_len - 1, dim_per_head)
batch_size, seq_length = hidden_states.shape[:2]
real_seq_length = seq_length
if past_key_value is not None:
if len(past_key_value) != 2:
raise ValueError(
f"past_key_value should have 2 past states: keys and values. Got { len(past_key_value)} past states"
)
real_seq_length += past_key_value[0].shape[2] if query_length is None else query_length
key_length = real_seq_length if key_value_states is None else key_value_states.shape[1]
def shape(states):
"""projection"""
return states.view(batch_size, -1, self.n_heads, self.key_value_proj_dim)
def unshape(states):
"""reshape"""
return states.view(batch_size, -1, self.inner_dim)
def project(hidden_states, proj_layer, key_value_states, past_key_value):
"""projects hidden states correctly to key/query states"""
if key_value_states is None:
# self-attn
# (batch_size, n_heads, seq_length, dim_per_head)
hidden_states = shape(proj_layer(hidden_states))
elif past_key_value is None:
# cross-attn
# (batch_size, n_heads, seq_length, dim_per_head)
hidden_states = shape(proj_layer(key_value_states))
if past_key_value is not None:
if key_value_states is None:
# self-attn
# (batch_size, n_heads, key_length, dim_per_head)
hidden_states = torch.cat([past_key_value, hidden_states], dim=1)
elif past_key_value.shape[1] != key_value_states.shape[1]:
# checking that the `sequence_length` of the `past_key_value` is the same as
# the provided `key_value_states` to support prefix tuning
# cross-attn
# (batch_size, n_heads, seq_length, dim_per_head)
hidden_states = shape(proj_layer(key_value_states))
else:
# cross-attn
hidden_states = past_key_value
return hidden_states
# get query states
query_states = shape(self.q(hidden_states)) # (batch_size, n_heads, seq_length, dim_per_head)
# get key/value states
key_states = project(
hidden_states, self.k, key_value_states, past_key_value[0] if past_key_value is not None else None
)
value_states = project(
hidden_states, self.v, key_value_states, past_key_value[1] if past_key_value is not None else None
)
if position_bias is None:
if not self.has_relative_attention_bias:
position_bias = torch.zeros(
(1, self.n_heads, real_seq_length, key_length), device=query_states.device, dtype=query_states.dtype
)
if self.gradient_checkpointing and self.training:
position_bias.requires_grad = True
else:
position_bias = self.compute_bias(real_seq_length, key_length, device=query_states.device)
# if key and values are already calculated
# we want only the last query position bias
if past_key_value is not None:
position_bias = position_bias[:, :, -hidden_states.size(1) :, :]
if mask is not None:
position_bias = position_bias + mask # (batch_size, n_heads, seq_length, key_length)
if self.pruned_heads:
mask = torch.ones(position_bias.shape[1])
mask[list(self.pruned_heads)] = 0
position_bias_masked = position_bias[:, mask.bool()]
else:
position_bias_masked = position_bias
position_bias_masked = position_bias_masked.contiguous()
attn_output = me_attention(
query_states, key_states, value_states, attn_bias=position_bias_masked, p=self.dropout, scale=1.0
)
attn_output = unshape(attn_output)
attn_output = self.o(attn_output)
present_key_value_state = (key_states, value_states) if (self.is_decoder and use_cache) else None
outputs = (attn_output,) + (present_key_value_state,) + (position_bias,)
return outputs
return forward
def get_jit_fused_T5_layer_ff_forward():
from transformers.models.t5.modeling_t5 import T5LayerFF
def forward(self: T5LayerFF, hidden_states: torch.Tensor) -> torch.Tensor:
forwarded_states = self.layer_norm(hidden_states)
forwarded_states = self.DenseReluDense(forwarded_states)
hidden_states = self.dropout_add(forwarded_states, hidden_states, self.dropout.p, self.dropout.training)
return hidden_states
return forward
def get_T5_layer_self_attention_forward():
from transformers.models.t5.modeling_t5 import T5LayerSelfAttention
def forward(
self: T5LayerSelfAttention,
hidden_states: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
position_bias: Optional[torch.Tensor] = None,
layer_head_mask: Optional[torch.Tensor] = None,
past_key_value: Optional[Tuple[torch.Tensor]] = None,
use_cache: bool = False,
output_attentions: bool = False,
) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[torch.Tensor]]:
normed_hidden_states = self.layer_norm(hidden_states)
attention_output = self.SelfAttention(
normed_hidden_states,
mask=attention_mask,
position_bias=position_bias,
layer_head_mask=layer_head_mask,
past_key_value=past_key_value,
use_cache=use_cache,
output_attentions=output_attentions,
)
hidden_states = self.dropout_add(attention_output[0], hidden_states, self.dropout.p, self.dropout.training)
outputs = (hidden_states,) + attention_output[1:] # add attentions if we output them
return outputs
return forward
def get_T5_layer_cross_attention_forward():
from transformers.models.t5.modeling_t5 import T5LayerCrossAttention
def forward(
self: T5LayerCrossAttention,
hidden_states: torch.Tensor,
key_value_states: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
position_bias: Optional[torch.Tensor] = None,
layer_head_mask: Optional[torch.Tensor] = None,
past_key_value: Optional[Tuple[torch.Tensor]] = None,
use_cache: bool = False,
query_length: Optional[int] = None,
output_attentions: bool = False,
) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[torch.Tensor]]:
normed_hidden_states = self.layer_norm(hidden_states)
attention_output = self.EncDecAttention(
normed_hidden_states,
mask=attention_mask,
key_value_states=key_value_states,
position_bias=position_bias,
layer_head_mask=layer_head_mask,
past_key_value=past_key_value,
use_cache=use_cache,
query_length=query_length,
output_attentions=output_attentions,
)
layer_output = self.dropout_add(attention_output[0], hidden_states, self.dropout.p, self.dropout.training)
outputs = (layer_output,) + attention_output[1:] # add attentions if we output them
return outputs
return forward