Harry Mellor 1f9460c4c1
Fix pooling adapters for Transformers backend (#27338)
Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
2025-10-23 20:23:55 -07:00

91 lines
3.1 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Copyright 2024 The vLLM team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Transformers backend mixin for legacy models."""
from typing import TYPE_CHECKING
import torch
from vllm.model_executor.models.utils import WeightsMapper
from vllm.sequence import IntermediateTensors
if TYPE_CHECKING:
from vllm.config import VllmConfig
class LegacyMixin:
hf_to_vllm_mapper = WeightsMapper(
# These are applied in order, so the order matters!
orig_to_new_prefix={
# Handle BERT-like models
"roberta": "model",
"bert": "model",
},
orig_to_new_suffix={
# Replace legacy suffixes used for norms
".gamma": ".weight",
".beta": ".bias",
},
)
def __init__(self, *, vllm_config: "VllmConfig", prefix: str = ""):
super().__init__(vllm_config=vllm_config, prefix=prefix)
# Skip unsupported/unwanted output embeddings layers
self.skip_prefixes.extend(
[
"model.lm_head.",
"model.predictions.",
"model.qa_outputs.",
"model.embeddings_project.",
"model.discriminator_predictions.",
]
)
# Some encoder models have the position_ids buffer in the checkpoint.
# vLLM will always pass position_ids as an argument, so we skip loading
# the buffer if it exists
self.skip_substrs.append("position_ids")
# Some encoder models have the bias of the final classifier layer
# in the checkpoint. vLLM does not use this bias, so we skip loading
# it if it exists
self.skip_substrs.append("score.bias")
# roberta-like models an extra padding in positions.
# FIXME(Isotr0py): This is quite hacky for roberta edge case,
# we should find a better way to handle this.
self.is_roberta = "roberta" in self.text_config.model_type
self.padding_idx = self.text_config.pad_token_id
def forward(
self,
input_ids: torch.Tensor | None,
positions: torch.Tensor,
intermediate_tensors: IntermediateTensors | None = None,
inputs_embeds: torch.Tensor | None = None,
) -> torch.Tensor | IntermediateTensors:
if self.is_roberta:
# RoBERTa-specific positions padding
positions += self.padding_idx + 1
return super().forward(
input_ids=input_ids,
positions=positions,
intermediate_tensors=intermediate_tensors,
inputs_embeds=inputs_embeds,
)