certifaier / vllm /model_executor /layers /vocab_parallel_embedding.py
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from typing import Optional, Sequence
import torch
import torch.nn.functional as F
from torch.nn.parameter import Parameter
from vllm.model_executor.parallel_utils.parallel_state import (
get_tensor_model_parallel_rank,
get_tensor_model_parallel_world_size,
)
from vllm.model_executor.parallel_utils.utils import divide
from vllm.model_executor.parallel_utils.communication_op import (
tensor_model_parallel_all_reduce)
from vllm.model_executor.utils import set_weight_attrs
DEFAULT_VOCAB_PADDING_SIZE = 64
def pad_vocab_size(vocab_size: int,
pad_to: int = DEFAULT_VOCAB_PADDING_SIZE) -> int:
"""Pad the vocab size to the given value."""
return ((vocab_size + pad_to - 1) // pad_to) * pad_to
def vocab_range_from_per_partition_vocab_size(per_partition_vocab_size: int,
rank: int) -> Sequence[int]:
index_f = rank * per_partition_vocab_size
index_l = index_f + per_partition_vocab_size
return index_f, index_l
def vocab_range_from_global_vocab_size(global_vocab_size: int, rank: int,
world_size: int) -> Sequence[int]:
per_partition_vocab_size = divide(global_vocab_size, world_size)
return vocab_range_from_per_partition_vocab_size(per_partition_vocab_size,
rank)
class VocabParallelEmbedding(torch.nn.Module):
"""Embedding parallelized in the vocabulary dimension.
Adapted from torch.nn.Embedding, note that we pad the vocabulary size to
make sure it is divisible by the number of model parallel GPUs.
Args:
num_embeddings: vocabulary size.
embedding_dim: size of hidden state.
params_dtype: type of the parameters.
org_num_embeddings: original vocabulary size (without LoRA).
padding_size: padding size for the vocabulary.
"""
def __init__(self,
num_embeddings: int,
embedding_dim: int,
params_dtype: Optional[torch.dtype] = None,
org_num_embeddings: Optional[int] = None,
padding_size: int = DEFAULT_VOCAB_PADDING_SIZE):
super().__init__()
# Keep the input dimensions.
self.num_embeddings = num_embeddings
self.org_vocab_size = org_num_embeddings or num_embeddings
self.num_embeddings_padded = pad_vocab_size(num_embeddings,
padding_size)
self.embedding_dim = embedding_dim
if params_dtype is None:
params_dtype = torch.get_default_dtype()
self.tp_size = get_tensor_model_parallel_world_size()
# Divide the weight matrix along the vocaburaly dimension.
self.vocab_start_index, self.vocab_end_index = (
vocab_range_from_global_vocab_size(
self.num_embeddings_padded, get_tensor_model_parallel_rank(),
self.tp_size))
self.num_embeddings_per_partition = (self.vocab_end_index -
self.vocab_start_index)
self.weight = Parameter(
torch.empty(self.num_embeddings_per_partition,
self.embedding_dim,
device=torch.cuda.current_device(),
dtype=params_dtype))
set_weight_attrs(self.weight, {
"parallel_dim": 0,
"weight_loader": self.weight_loader
})
def weight_loader(self, param: Parameter, loaded_weight: torch.Tensor):
parallel_dim = param.parallel_dim
assert loaded_weight.shape[parallel_dim] == self.org_vocab_size
loaded_weight = loaded_weight[self.vocab_start_index:self.
vocab_end_index]
param[:loaded_weight.shape[0]].data.copy_(loaded_weight)
def forward(self, input_):
if self.tp_size > 1:
# Build the mask.
input_mask = ((input_ < self.vocab_start_index) |
(input_ >= self.vocab_end_index))
# Mask the input.
masked_input = input_.clone() - self.vocab_start_index
masked_input[input_mask] = 0
else:
masked_input = input_
# Get the embeddings.
output_parallel = F.embedding(masked_input, self.weight)
# Mask the output embedding.
if self.tp_size > 1:
output_parallel[input_mask, :] = 0.0
# Reduce across all the model parallel GPUs.
output = tensor_model_parallel_all_reduce(output_parallel)
return output
class ParallelLMHead(VocabParallelEmbedding):
"""Parallelized LM head.
Output logits weight matrices used in the Sampler. The weight and bias
tensors are padded to make sure they are divisible by the number of
model parallel GPUs.
Args:
num_embeddings: vocabulary size.
embedding_dim: size of hidden state.
bias: whether to use bias.
params_dtype: type of the parameters.
org_num_embeddings: original vocabulary size (without LoRA).
padding_size: padding size for the vocabulary.
"""
def __init__(self,
num_embeddings: int,
embedding_dim: int,
bias: bool = False,
params_dtype: Optional[torch.dtype] = None,
org_num_embeddings: Optional[int] = None,
padding_size: int = DEFAULT_VOCAB_PADDING_SIZE):
super().__init__(num_embeddings, embedding_dim, params_dtype,
org_num_embeddings, padding_size)
if bias:
self.bias = Parameter(
torch.empty(self.num_embeddings_per_partition,
device=torch.cuda.current_device(),
dtype=params_dtype))
set_weight_attrs(self.bias, {
"parallel_dim": 0,
"weight_loader": self.weight_loader
})
else:
self.register_parameter("bias", None)
def forward(self, input_):
del input_
raise RuntimeError("LMHead's weights should be used in the sampler.")