Files
sglang/python/sglang/srt/layers/utils.py
2025-09-27 05:05:23 +00:00

60 lines
1.9 KiB
Python

import logging
import re
from functools import lru_cache
import torch
logger = logging.getLogger(__name__)
def get_layer_id(weight_name):
# example weight name: model.layers.10.self_attn.qkv_proj.weight
match = re.search(r"layers\.(\d+)\.", weight_name)
if match:
return int(match.group(1))
return None
def pad_or_narrow_weight(
loaded_weight: torch.Tensor, input_dim: int, start_idx: int, shard_size: int
) -> torch.Tensor:
# Padding with zeros for special case such as qwen2_5_VL's mlp which is not 8-aligned
valid_size = max(loaded_weight.shape[input_dim] - start_idx, 0)
if valid_size > 0:
loaded_slice = loaded_weight.narrow(input_dim, start_idx, valid_size)
pad_shape = list(loaded_weight.shape)
pad_shape[input_dim] = shard_size - valid_size
pad = torch.zeros(
pad_shape, dtype=loaded_weight.dtype, device=loaded_weight.device
)
return torch.cat([loaded_slice, pad], dim=input_dim)
# All padding
pad_shape = list(loaded_weight.shape)
pad_shape[input_dim] = shard_size
return torch.zeros(
pad_shape, dtype=loaded_weight.dtype, device=loaded_weight.device
)
class PPMissingLayer(torch.nn.Identity):
# Adapted from
# https://github.com/vllm-project/vllm/blob/18ed3132d2bfe1df9a74729457b69243955221e8/vllm/model_executor/models/utils.py#L468C1-L486C1
"""
A placeholder layer for missing layers in a pipeline parallel model.
"""
def __init__(self, *args, **kwargs):
super().__init__()
self.return_tuple = kwargs.get("return_tuple", False)
def forward(self, *args, **kwargs):
"""
Return the first arg from args or the first value from kwargs.
Wraps the input in a tuple if `self.return_tuple` is True.
"""
input = args[0] if args else next(iter(kwargs.values()))
return (input,) if self.return_tuple else input