Files
2026-03-05 18:06:10 +08:00

114 lines
3.3 KiB
Python

from typing import Any, Dict, List, Optional
import torch
from torch.nn.parameter import Parameter
from vllm import _custom_ops as ops
from vllm.model_executor.layers.linear import LinearBase, LinearMethodBase
from vllm.model_executor.layers.quantization.base_config import (
QuantizationConfig)
from vllm.model_executor.parameter import (GroupQuantScaleParameter,
PackedvLLMParameter)
from vllm.model_executor.utils import set_weight_attrs
class W8a16Config(QuantizationConfig):
"""Config class for W8a16.
"""
def __init__(
self,
) -> None:
pass
def __repr__(self) -> str:
return ("W8a16Config")
def get_name(self) -> str:
return "w8a16"
def get_supported_act_dtypes(self) -> List[torch.dtype]:
return [torch.half, torch.bfloat16]
def get_min_capability(self) -> int:
return 75
@staticmethod
def get_config_filenames():
return []
@classmethod
def from_config(cls, config: Dict[str, Any]) -> "W8a16Config":
return cls()
def get_quant_method(self, layer: torch.nn.Module,
prefix: str) -> Optional["W8a16LinearMethod"]:
if isinstance(layer, LinearBase):
return W8a16LinearMethod(self)
return None
def get_scaled_act_names(self) -> List[str]:
return []
class W8a16LinearMethod(LinearMethodBase):
"""Linear method for w8a16.
"""
def __init__(self, quant_config: W8a16Config):
self.quant_config = quant_config
def create_weights(self, layer: torch.nn.Module,
input_size_per_partition: int,
output_partition_sizes: List[int], input_size: int,
output_size: int, params_dtype: torch.dtype,
**extra_weight_attrs):
output_size_per_partition = sum(output_partition_sizes)
weight = Parameter(
torch.empty(
output_size_per_partition,
input_size_per_partition,
dtype=torch.int8,
),
requires_grad=False,
)
set_weight_attrs(
weight, {
"input_dim": 1,
"output_dim": 0,
})
scales = Parameter(
torch.empty(
1,
output_size_per_partition,
dtype=params_dtype,
),
requires_grad=False,
)
set_weight_attrs(scales, {
"input_dim": None,
"output_dim": 1,
})
layer.register_parameter("weight", weight)
set_weight_attrs(weight, extra_weight_attrs)
layer.register_parameter("scales", scales)
set_weight_attrs(scales, extra_weight_attrs)
def apply(self,
layer: torch.nn.Module,
x: torch.Tensor,
bias: Optional[torch.Tensor] = None) -> torch.Tensor:
qweight = layer.weight
scales = layer.scales
out_shape = (x.shape[:-1] + (qweight.shape[-2],))
reshaped_x = x.reshape(-1, x.shape[-1])
out = ops.linear_w8a16(reshaped_x, qweight, scales, format="TN")
if bias is not None:
out = out + bias
return out.reshape(out_shape)