2024-10-23 11:27:37 +00:00

447 lines
16 KiB
Python

"""Minimal implementation of BlipVisionModel intended to be only used
within a vision language model."""
from typing import Iterable, Optional, Tuple, Union
import torch
import torch.nn as nn
from PIL import Image
from transformers import Blip2VisionConfig, BlipVisionConfig
from transformers.models.blip.modeling_blip import BlipAttention
from vllm.config import ModelConfig
from vllm.distributed import divide, get_tensor_model_parallel_world_size
from vllm.inputs import DecoderOnlyInputs, token_inputs
from vllm.model_executor.layers.activation import get_act_fn
from vllm.model_executor.layers.linear import (ColumnParallelLinear,
QKVParallelLinear,
RowParallelLinear)
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.model_loader.weight_utils import default_weight_loader
from vllm.multimodal.utils import (cached_get_tokenizer,
repeat_and_pad_placeholder_tokens)
from vllm.sequence import SequenceData
try:
from xformers import ops as xops
USE_XFORMERS_OPS = True
except ImportError:
USE_XFORMERS_OPS = False
def get_blip_patch_grid_length(*, image_size: int, patch_size: int) -> int:
assert image_size % patch_size == 0
return image_size // patch_size
def get_blip_num_patches(*, image_size: int, patch_size: int) -> int:
grid_length = get_blip_patch_grid_length(image_size=image_size,
patch_size=patch_size)
return grid_length * grid_length
def get_blip_image_feature_size(
hf_config: Union[BlipVisionConfig, Blip2VisionConfig]) -> int:
return get_blip_num_patches(image_size=hf_config.image_size,
patch_size=hf_config.patch_size)
def get_max_blip_image_tokens(
hf_config: Union[BlipVisionConfig, Blip2VisionConfig]) -> int:
return get_blip_image_feature_size(hf_config)
def dummy_seq_data_for_blip(
hf_config: Union[BlipVisionConfig, Blip2VisionConfig],
seq_len: int,
num_images: int,
*,
image_token_id: int,
image_feature_size_override: Optional[int] = None,
):
if image_feature_size_override is None:
image_feature_size = get_blip_image_feature_size(hf_config)
else:
image_feature_size = image_feature_size_override
return SequenceData.from_prompt_token_counts(
(image_token_id, image_feature_size * num_images),
(0, seq_len - image_feature_size * num_images),
)
def dummy_image_for_blip(
hf_config: Union[BlipVisionConfig, Blip2VisionConfig],
num_images: int,
*,
image_width_override: Optional[int] = None,
image_height_override: Optional[int] = None,
):
width = height = hf_config.image_size
if image_width_override is not None:
width = image_width_override
if image_height_override is not None:
height = image_height_override
image = Image.new("RGB", (width, height), color=0)
return {"image": image if num_images == 1 else [image] * num_images}
def input_processor_for_blip(
model_config: ModelConfig,
hf_config: Union[BlipVisionConfig, Blip2VisionConfig],
inputs: DecoderOnlyInputs,
*,
image_token_id: int,
image_feature_size_override: Optional[int] = None,
):
multi_modal_data = inputs.get("multi_modal_data")
if multi_modal_data is None or "image" not in multi_modal_data:
return inputs
tokenizer = cached_get_tokenizer(model_config.tokenizer)
if image_feature_size_override is None:
image_feature_size = get_blip_image_feature_size(hf_config)
else:
image_feature_size = image_feature_size_override
new_prompt, new_token_ids = repeat_and_pad_placeholder_tokens(
tokenizer,
inputs.get("prompt"),
inputs["prompt_token_ids"],
placeholder_token_id=image_token_id,
repeat_count=image_feature_size,
)
# NOTE: Create a defensive copy of the original inputs
return token_inputs(prompt_token_ids=new_token_ids,
prompt=new_prompt,
multi_modal_data=multi_modal_data)
# Adapted from https://github.com/huggingface/transformers/blob/v4.39.0/src/transformers/models/blip/modeling_blip.py#L164 # noqa
class BlipVisionEmbeddings(nn.Module):
def __init__(self, config: Union[BlipVisionConfig, Blip2VisionConfig]):
super().__init__()
self.config = config
self.embed_dim = config.hidden_size
self.image_size = config.image_size
self.patch_size = config.patch_size
self.class_embedding = nn.Parameter(torch.randn(1, 1, self.embed_dim))
self.patch_embedding = nn.Conv2d(
in_channels=3,
out_channels=self.embed_dim,
kernel_size=self.patch_size,
stride=self.patch_size,
)
self.num_patches = get_blip_num_patches(image_size=self.image_size,
patch_size=self.patch_size)
self.num_positions = self.num_patches + 1
self.position_embedding = nn.Parameter(
torch.randn(1, self.num_positions, self.embed_dim))
def forward(self, pixel_values: torch.Tensor) -> torch.Tensor:
batch_size = pixel_values.shape[0]
target_dtype = self.patch_embedding.weight.dtype
patch_embeds = self.patch_embedding(pixel_values.to(
dtype=target_dtype)) # shape = [*, width, grid, grid]
patch_embeds = patch_embeds.flatten(2).transpose(1, 2)
class_embeds = self.class_embedding.expand(batch_size, 1, -1)
embeddings = torch.cat([class_embeds, patch_embeds], dim=1)
position_embeds = self.position_embedding.to(target_dtype)
embeddings = embeddings + position_embeds[:, :embeddings.size(1), :]
return embeddings
class BlipParallelAttention(nn.Module):
"""Multi-headed attention from 'Attention Is All You Need' paper"""
def __init__(
self,
config: Union[BlipVisionConfig, Blip2VisionConfig],
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
super().__init__()
self.config = config
self.embed_dim = config.hidden_size
self.num_heads = config.num_attention_heads
self.head_dim = self.embed_dim // self.num_heads
if self.head_dim * self.num_heads != self.embed_dim:
raise ValueError(
"embed_dim must be divisible by num_heads "
f"(got `embed_dim`: {self.embed_dim} and `num_heads`:"
f" {self.num_heads}).")
self.scale = self.head_dim**-0.5
self.dropout = config.attention_dropout
self.qkv = QKVParallelLinear(
self.embed_dim,
self.head_dim,
self.num_heads,
bias=config.qkv_bias,
quant_config=quant_config,
prefix=f"{prefix}.qkv",
)
self.projection = RowParallelLinear(
self.embed_dim,
self.embed_dim,
quant_config=quant_config,
prefix=f"{prefix}.projection",
)
self.tp_size = get_tensor_model_parallel_world_size()
self.num_heads_per_partition = divide(self.num_heads, self.tp_size)
def _shape(self, tensor: torch.Tensor, seq_len: int, bsz: int):
return tensor.view(bsz, seq_len, self.num_heads,
self.head_dim).transpose(1, 2).contiguous()
def forward(
self,
hidden_states: torch.Tensor,
):
"""Input shape: Batch x Time x Channel"""
bsz, tgt_len, _ = hidden_states.size()
qkv_states, _ = self.qkv(hidden_states)
query_states, key_states, value_states = qkv_states.chunk(3, dim=-1)
query_states = query_states.view(bsz, tgt_len,
self.num_heads_per_partition,
self.head_dim)
key_states = key_states.view(bsz, tgt_len,
self.num_heads_per_partition,
self.head_dim)
value_states = value_states.view(bsz, tgt_len,
self.num_heads_per_partition,
self.head_dim)
out = xops.memory_efficient_attention_forward(query_states,
key_states,
value_states,
p=self.dropout,
scale=self.scale)
out = out.view(bsz, tgt_len, -1)
attn_output, _ = self.projection(out)
return attn_output, None
class BlipMLP(nn.Module):
def __init__(
self,
config: BlipVisionConfig,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
super().__init__()
self.config = config
self.activation_fn = get_act_fn(config.hidden_act)
self.fc1 = ColumnParallelLinear(config.hidden_size,
config.intermediate_size,
bias=True,
quant_config=quant_config,
prefix=f"{prefix}.fc1")
self.fc2 = RowParallelLinear(config.intermediate_size,
config.hidden_size,
bias=True,
quant_config=quant_config,
prefix=f"{prefix}.fc2")
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
hidden_states, _ = self.fc1(hidden_states)
hidden_states = self.activation_fn(hidden_states)
hidden_states, _ = self.fc2(hidden_states)
return hidden_states
class BlipEncoderLayer(nn.Module):
def __init__(
self,
config: BlipVisionConfig,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
super().__init__()
# fallback to sdpa attention if tp unavailable
num_heads = config.num_attention_heads
tp_size = get_tensor_model_parallel_world_size()
if USE_XFORMERS_OPS and num_heads % tp_size == 0:
self.self_attn = BlipParallelAttention(
config,
quant_config=quant_config,
prefix=f"{prefix}.self_attn",
)
else:
# Blip doesn't have SDPA attention implemented in transformers
# use eager attention instead for cpu backend
self.self_attn = BlipAttention(config)
self.layer_norm1 = nn.LayerNorm(config.hidden_size,
eps=config.layer_norm_eps)
self.mlp = BlipMLP(config,
quant_config=quant_config,
prefix=f"{prefix}.mlp")
self.layer_norm2 = nn.LayerNorm(config.hidden_size,
eps=config.layer_norm_eps)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
residual = hidden_states
hidden_states = self.layer_norm1(hidden_states)
hidden_states, _ = self.self_attn(hidden_states=hidden_states)
hidden_states = residual + hidden_states
residual = hidden_states
hidden_states = self.layer_norm2(hidden_states)
hidden_states = self.mlp(hidden_states)
hidden_states = residual + hidden_states
return hidden_states
class BlipEncoder(nn.Module):
"""
Transformer encoder consisting of `config.num_hidden_layers` self
attention layers. Each layer is a [`BlipEncoderLayer`].
Args:
config: BlipConfig
"""
def __init__(
self,
config: BlipVisionConfig,
quant_config: Optional[QuantizationConfig] = None,
num_hidden_layers_override: Optional[int] = None,
prefix: str = "",
) -> None:
super().__init__()
self.config = config
if num_hidden_layers_override is None:
num_hidden_layers = config.num_hidden_layers
else:
num_hidden_layers = num_hidden_layers_override
self.layers = nn.ModuleList([
BlipEncoderLayer(config=config,
quant_config=quant_config,
prefix=f"{prefix}.layers.{layer_idx}")
for layer_idx in range(num_hidden_layers)
])
def forward(self, inputs_embeds: torch.Tensor):
hidden_states = inputs_embeds
for encoder_layer in self.layers:
hidden_states = encoder_layer(hidden_states)
return hidden_states
class BlipVisionModel(nn.Module):
config_class = BlipVisionConfig
main_input_name = "pixel_values"
def __init__(
self,
config: BlipVisionConfig,
quant_config: Optional[QuantizationConfig] = None,
*,
num_hidden_layers_override: Optional[int] = None,
require_post_norm: Optional[bool] = None,
prefix: str = "",
) -> None:
super().__init__()
tp_size = get_tensor_model_parallel_world_size()
num_heads = config.num_attention_heads
self.shard_weight = USE_XFORMERS_OPS and num_heads % tp_size == 0
self.config = config
self.embeddings = BlipVisionEmbeddings(config)
self.encoder = BlipEncoder(
config=config,
quant_config=quant_config,
num_hidden_layers_override=num_hidden_layers_override,
prefix=f"{prefix}.encoder",
)
num_hidden_layers = config.num_hidden_layers
if len(self.encoder.layers) > config.num_hidden_layers:
raise ValueError(
f"The original encoder only has {num_hidden_layers} "
f"layers, but you requested {len(self.encoder.layers)} layers."
)
# If possible, skip post_layernorm to conserve memory
if require_post_norm is None:
require_post_norm = len(self.encoder.layers) == num_hidden_layers
if require_post_norm:
self.post_layernorm = nn.LayerNorm(config.hidden_size,
eps=config.layer_norm_eps)
else:
self.post_layernorm = None
def forward(self, pixel_values: torch.Tensor) -> torch.Tensor:
hidden_states = self.embeddings(pixel_values)
hidden_states = self.encoder(inputs_embeds=hidden_states)
if self.post_layernorm is None:
return hidden_states
return self.post_layernorm(hidden_states)
def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
stacked_params_mapping = [
# (param_name, shard_name, shard_id)
("qkv_proj", "q_proj", "q"),
("qkv_proj", "k_proj", "k"),
("qkv_proj", "v_proj", "v"),
] if self.shard_weight else []
params_dict = dict(self.named_parameters())
layer_count = len(self.encoder.layers)
for name, loaded_weight in weights:
# post_layernorm is not needed in BlipVisionModel
if (name.startswith("post_layernorm")
and self.post_layernorm is None):
continue
# omit layers when num_hidden_layers_override is set
if name.startswith("encoder.layers"):
layer_idx = int(name.split(".")[2])
if layer_idx >= layer_count:
continue
for (param_name, weight_name, shard_id) in stacked_params_mapping:
if weight_name not in name:
continue
param = params_dict[name.replace(weight_name, param_name)]
weight_loader = param.weight_loader
weight_loader(param, loaded_weight, shard_id)
break
else:
param = params_dict[name]
weight_loader = getattr(param, "weight_loader",
default_weight_loader)
weight_loader(param, loaded_weight)