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vLLM/vllm/model_executor/models/utils.py
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from typing import Callable, Dict, List, Tuple
import torch
from vllm.multimodal import BatchedTensors
def merge_vision_embeddings(input_ids: torch.Tensor,
inputs_embeds: torch.Tensor,
vision_embeddings: BatchedTensors,
image_token_id: int) -> torch.Tensor:
"""
Merge `vision_embeddings` into `inputs_embeds` by overwriting the positions
in `inputs_embeds` corresponding to placeholder image tokens in `input_ids`.
Note:
This updates `inputs_embeds` in place.
"""
mask = (input_ids == image_token_id)
num_expected_tokens = mask.sum()
if isinstance(vision_embeddings, torch.Tensor):
batch_size, batch_tokens, *_, embed_dim = vision_embeddings.shape
total_tokens = batch_size * batch_tokens
if num_expected_tokens != total_tokens:
expr = f"{batch_size} x {batch_tokens}"
raise ValueError(
f"Attempted to assign {expr} = {total_tokens} "
f"image tokens to {num_expected_tokens} placeholders")
inputs_embeds[mask] = vision_embeddings.view(total_tokens, embed_dim)
else:
size_per_batch = [t.shape[0] for t in vision_embeddings]
total_tokens = sum(size_per_batch)
if num_expected_tokens != total_tokens:
expr = ' + '.join(map(str, size_per_batch))
raise ValueError(
f"Attempted to assign {expr} = {total_tokens} "
f"image tokens to {num_expected_tokens} placeholders")
inputs_embeds[mask] = torch.cat(vision_embeddings)
return inputs_embeds
class PPMissingLayer(torch.nn.Identity):
"""
A placeholder layer for missing layers in a pipeline parallel model.
"""
def __init__(self, *args, **kwargs):
super().__init__()
def make_layers(
num_hidden_layers: int, layer_fn: Callable[[], torch.nn.Module]
) -> Tuple[int, int, torch.nn.ModuleList]:
"""Make a list of layers with the given layer function, taking
pipeline parallelism into account.
"""
from vllm.distributed.parallel_state import get_pp_group
from vllm.distributed.utils import get_pp_indices
start_layer, end_layer = get_pp_indices(num_hidden_layers,
get_pp_group().rank_in_group,
get_pp_group().world_size)
modules = torch.nn.ModuleList(
[PPMissingLayer() for _ in range(start_layer)] +
[layer_fn() for _ in range(start_layer, end_layer)] +
[PPMissingLayer() for _ in range(end_layer, num_hidden_layers)])
return start_layer, end_layer, modules
# NOTE: don't use lru_cache here because it can prevent garbage collection
_model_to_pp_missing_layer_names: Dict[int, List[str]] = {}
def get_pp_missing_layer_names(model: torch.nn.Module) -> List[str]:
"""Get the names of the missing layers in a pipeline parallel model."""
model_id = id(model)
if model_id in _model_to_pp_missing_layer_names:
return _model_to_pp_missing_layer_names[model_id]
missing_layer_names = []
for name, module in model.named_modules():
if isinstance(module, PPMissingLayer):
# NOTE: the trailing dot is used to match the prefix of the layer.
# without the dot, we could match a layer that is not missing,
# e.g., 'encoder.layer.1' would match 'encoder.layer.11'
missing_layer_names.append(name + '.')
_model_to_pp_missing_layer_names[model_id] = missing_layer_names
return missing_layer_names
def is_pp_missing_parameter(name: str, model: torch.nn.Module) -> bool:
"""Check if a parameter is missing in a pipeline parallel model."""
for missing_layer_name in get_pp_missing_layer_names(model):
if name.startswith(missing_layer_name):
return True
return False