Files
vllm-anthropic/vllm/model_executor/layers/quantization/fp_quant.py
Roberto L. Castro 96ad65b7fe [Transform] [Quantization] Add QuTLASS support to vLLM (#24440)
Signed-off-by: LopezCastroRoberto <roberto.lopez.castro@udc.es>
Signed-off-by: Roberto L. Castro <38211239+LopezCastroRoberto@users.noreply.github.com>
Signed-off-by: Andrei Panferov <andrei@panferov.org>
Co-authored-by: Andrei Panferov <andrei@panferov.org>
Co-authored-by: Michael Goin <mgoin64@gmail.com>
2025-10-10 09:43:40 -07:00

421 lines
13 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Supports FP-Quant compression, see https://arxiv.org/abs/2509.23202
from typing import Any, Optional
import torch
from torch.nn.parameter import Parameter
from vllm._custom_ops import (
cutlass_scaled_fp4_mm,
fusedQuantizeMx,
fusedQuantizeNv,
matmul_mxf4_bf16_tn,
)
from vllm.model_executor.layers.linear import (
LinearBase,
LinearMethodBase,
UnquantizedLinearMethod,
)
from vllm.model_executor.layers.quantization import QuantizationMethods
from vllm.model_executor.layers.quantization.base_config import QuantizationConfig
from vllm.model_executor.layers.quantization.qutlass_utils import to_blocked
from vllm.model_executor.utils import set_weight_attrs
from vllm.platforms import current_platform
from vllm.utils import direct_register_custom_op
class FPQuantConfig(QuantizationConfig):
"""Config class for FPQuant."""
def __init__(
self,
hadamard_group_size: int = 32,
forward_dtype: str = "mxfp4",
forward_method: str = "abs_max",
pseudoquantization: bool = False,
modules_to_not_convert: Optional[list[str]] = None,
) -> None:
super().__init__()
self.hadamard_group_size = hadamard_group_size
self.forward_dtype = forward_dtype
self.forward_method = forward_method
self.pseudoquantization = pseudoquantization
self.modules_to_not_convert = modules_to_not_convert
if pseudoquantization:
raise ValueError("Pseudoquantization is not supported for vLLM")
def __repr__(self) -> str:
return (
f"FPQuantConfig(hadamard_group_size={self.hadamard_group_size}, "
f"forward_dtype={self.forward_dtype}, "
f"forward_method={self.forward_method}, "
f"pseudoquantization={self.pseudoquantization}, "
f"modules_to_not_convert={self.modules_to_not_convert})"
)
@classmethod
def get_name(cls) -> QuantizationMethods:
return "fp_quant"
@classmethod
def get_supported_act_dtypes(cls) -> list[torch.dtype]:
return [torch.bfloat16]
@classmethod
def get_min_capability(cls) -> int:
return 100
@classmethod
def get_config_filenames(cls) -> list[str]:
return [] # no extra configs.
@classmethod
def from_config(cls, config: dict[str, Any]) -> "FPQuantConfig":
hadamard_group_size = cls.get_from_keys(config, ["hadamard_group_size"])
forward_dtype = cls.get_from_keys(config, ["forward_dtype"])
forward_method = cls.get_from_keys(config, ["forward_method"])
pseudoquantization = cls.get_from_keys(config, ["pseudoquantization"])
modules_to_not_convert = cls.get_from_keys(config, ["modules_to_not_convert"])
return cls(
hadamard_group_size,
forward_dtype,
forward_method,
pseudoquantization,
modules_to_not_convert,
)
def get_quant_method(
self, layer: torch.nn.Module, prefix: str
) -> Optional[LinearMethodBase]:
if self.modules_to_not_convert is not None and any(
prefix.endswith(module) for module in self.modules_to_not_convert
):
return UnquantizedLinearMethod()
if isinstance(layer, LinearBase):
return FPQuantLinearMethod(self)
return None
class FPQuantLinearMethod(LinearMethodBase):
"""Linear method for FPQuant.
Args:
quant_config: The FPQuant quantization config.
"""
def __init__(self, quant_config: FPQuantConfig):
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,
):
del output_size # Unused.
del input_size # Unused.
if params_dtype != torch.bfloat16:
raise ValueError("Only bfloat16 is currently supported by FPQuant")
if input_size_per_partition % self.quant_config.hadamard_group_size != 0: # noqa: E501
raise ValueError(
"The input size is not aligned with the quantized "
"weight shape. This can be caused by too large "
"tensor parallel size. Or other skill issues."
)
assert self.quant_config.forward_dtype in ["mxfp4", "nvfp4"], (
"Only mxfp4 and nvfp4 are supported for now"
)
if self.quant_config.forward_dtype == "mxfp4":
group_size = 32
elif self.quant_config.forward_dtype == "nvfp4":
group_size = 16
else:
raise ValueError(
f"Unsupported forward_dtype: {self.quant_config.forward_dtype}"
)
qweight = Parameter(
torch.empty(
sum(output_partition_sizes),
input_size_per_partition // 2,
dtype=torch.uint8,
),
requires_grad=False,
)
set_weight_attrs(
qweight,
{
"input_dim": 1,
"output_dim": 0,
"packed_dim": 1,
"pack_factor": 2,
}
| extra_weight_attrs,
)
layer.register_parameter("qweight", qweight)
scales = Parameter(
torch.empty(
sum(output_partition_sizes),
input_size_per_partition // group_size,
dtype=torch.uint8,
),
requires_grad=False,
)
set_weight_attrs(
scales,
{
"input_dim": 1,
"output_dim": 0,
"packed_dim": 1,
"pack_factor": group_size,
}
| extra_weight_attrs,
)
layer.register_parameter("scales", scales)
weight_global_scale = Parameter(
torch.empty(1, dtype=torch.float32),
requires_grad=False,
)
set_weight_attrs(
weight_global_scale, {"ignore_warning": True} | extra_weight_attrs
)
layer.register_parameter("weight_global_scale", weight_global_scale)
act_global_scale = Parameter(
torch.empty(1, dtype=torch.float32),
requires_grad=False,
)
set_weight_attrs(
act_global_scale, {"ignore_warning": True} | extra_weight_attrs
)
layer.register_parameter("act_global_scale", act_global_scale)
forward_hadamard_matrix = Parameter(
torch.empty(
self.quant_config.hadamard_group_size,
self.quant_config.hadamard_group_size,
dtype=params_dtype,
),
requires_grad=False,
)
set_weight_attrs(
forward_hadamard_matrix, {"ignore_warning": True} | extra_weight_attrs
)
layer.register_parameter("forward_hadamard_matrix", forward_hadamard_matrix)
backward_hadamard_matrix = Parameter(
torch.empty(
self.quant_config.hadamard_group_size,
self.quant_config.hadamard_group_size,
dtype=params_dtype,
),
requires_grad=False,
)
set_weight_attrs(
backward_hadamard_matrix, {"ignore_warning": True} | extra_weight_attrs
)
layer.register_parameter("backward_hadamard_matrix", backward_hadamard_matrix)
def apply(
self,
layer: torch.nn.Module,
x: torch.Tensor,
bias: Optional[torch.Tensor] = None,
) -> torch.Tensor:
return quantized_forward(
x,
layer.qweight,
layer.scales,
layer.weight_global_scale,
layer.act_global_scale,
bias,
layer.forward_hadamard_matrix,
self.quant_config.forward_method,
self.quant_config.forward_dtype,
)
def ceil_div(a, b):
return (a + b - 1) // b
def fused_quantize_mx(
x_flat: torch.Tensor, hadamard_matrix: torch.Tensor, forward_method: str
) -> tuple[torch.Tensor, torch.Tensor]:
return fusedQuantizeMx(x_flat, hadamard_matrix, method=forward_method)
def fused_quantize_mx_fake(x_flat, hadamard_matrix, forward_method):
rows, cols = x_flat.size(0), x_flat.size(1) // 32
padded_rows = ((rows + 128 - 1) // 128) * 128
padded_cols = ((cols + 4 - 1) // 4) * 4
xh_e2m1 = torch.empty(
x_flat.size(0), x_flat.size(1) // 2, dtype=torch.uint8, device=x_flat.device
)
xh_e8m0 = torch.empty(
padded_rows, padded_cols, dtype=torch.float8_e8m0fnu, device=x_flat.device
)
return xh_e2m1, xh_e8m0
direct_register_custom_op(
op_name="fused_quantize_mx",
op_func=fused_quantize_mx,
mutates_args=[],
fake_impl=fused_quantize_mx_fake,
dispatch_key=current_platform.dispatch_key,
)
def matmul_mxf4_bf16(
x: torch.Tensor,
w: torch.Tensor,
xs: torch.Tensor,
ws: torch.Tensor,
alpha: torch.Tensor,
) -> torch.Tensor:
return matmul_mxf4_bf16_tn(
x,
w,
to_blocked(xs, backend="triton").view(torch.float8_e8m0fnu),
to_blocked(ws, backend="triton").view(torch.float8_e8m0fnu),
alpha,
)
def matmul_mxf4_bf16_fake(x, w, xs, ws, alpha):
return torch.empty(*x.shape[:-1], w.shape[0], dtype=torch.bfloat16, device=x.device)
direct_register_custom_op(
op_name="matmul_mxf4_bf16",
op_func=matmul_mxf4_bf16,
mutates_args=[],
fake_impl=matmul_mxf4_bf16_fake,
dispatch_key=current_platform.dispatch_key,
)
def fused_quantize_nv(
x_flat: torch.Tensor, hadamard_matrix: torch.Tensor, global_scale: torch.Tensor
) -> tuple[torch.Tensor, torch.Tensor]:
return fusedQuantizeNv(x_flat, hadamard_matrix, global_scale)
def fused_quantize_nv_fake(x_flat, hadamard_matrix, global_scale):
rows, cols = x_flat.size(0), x_flat.size(1) // 16
padded_rows = ((rows + 128 - 1) // 128) * 128
padded_cols = ((cols + 4 - 1) // 4) * 4
xh_e2m1 = torch.empty(
x_flat.size(0), x_flat.size(1) // 2, dtype=torch.uint8, device=x_flat.device
)
xh_e8m0 = torch.empty(
padded_rows, padded_cols, dtype=torch.float8_e4m3fn, device=x_flat.device
)
return xh_e2m1, xh_e8m0
direct_register_custom_op(
op_name="fused_quantize_nv",
op_func=fused_quantize_nv,
mutates_args=[],
fake_impl=fused_quantize_nv_fake,
dispatch_key=current_platform.dispatch_key,
)
def matmul_nvf4_bf16(
x: torch.Tensor,
w: torch.Tensor,
xs: torch.Tensor,
ws: torch.Tensor,
alpha: torch.Tensor,
) -> torch.Tensor:
return cutlass_scaled_fp4_mm(
x,
w,
to_blocked(xs, backend="triton")
.view(torch.float8_e4m3fn)
.view(-1, x.shape[1] // 8), # *2//16
to_blocked(ws, backend="triton")
.view(torch.float8_e4m3fn)
.view(-1, x.shape[1] // 8),
alpha,
torch.bfloat16,
)
def matmul_nvf4_bf16_fake(x, w, xs, ws, alpha):
return torch.empty(*x.shape[:-1], w.shape[0], dtype=torch.bfloat16, device=x.device)
direct_register_custom_op(
op_name="matmul_nvf4_bf16",
op_func=matmul_nvf4_bf16,
mutates_args=[],
fake_impl=matmul_nvf4_bf16_fake,
dispatch_key=current_platform.dispatch_key,
)
def quantized_forward(
x: torch.Tensor,
qweight: torch.Tensor,
weight_scales: torch.Tensor,
weight_global_scale: torch.Tensor,
act_global_scale: torch.Tensor,
bias: Optional[torch.Tensor],
forward_hadamard_matrix: torch.Tensor,
forward_method: str,
forward_dtype: str,
) -> torch.Tensor:
x_flat = x.contiguous().flatten(end_dim=-2)
if forward_dtype == "mxfp4":
x_flat_q, x_flat_scales = torch.ops.vllm.fused_quantize_mx(
x_flat, forward_hadamard_matrix, forward_method
)
y = torch.ops.vllm.matmul_mxf4_bf16(
x_flat_q,
qweight,
x_flat_scales,
weight_scales,
1 / (weight_global_scale * act_global_scale),
)
elif forward_dtype == "nvfp4":
x_flat_q, x_flat_scales = torch.ops.vllm.fused_quantize_nv(
x_flat, forward_hadamard_matrix, act_global_scale
)
y = torch.ops.vllm.matmul_nvf4_bf16(
x_flat_q,
qweight,
x_flat_scales,
weight_scales,
1 / (weight_global_scale * act_global_scale),
)
else:
raise ValueError(f"Unsupported forward_dtype: {forward_dtype}")
y = y.view(*x.shape[:-1], y.shape[-1])
if bias is not None:
y += bias
return y