Files
sglang/python/sglang/srt/layers/amx_utils.py
jianan-gu c35aa0238c [CPU][INT4] Add INT4 kernels for CPU (#8226)
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
2026-01-29 22:30:13 -08:00

140 lines
4.4 KiB
Python

import logging
import torch
from sglang.srt.utils import cpu_has_amx_support
logger = logging.getLogger(__name__)
from enum import IntEnum
class CPUQuantMethod(IntEnum):
UNQUANT = 0
INT8_W8A8 = 1
FP8_W8A16 = 2
INT4_W4A8 = 3
def amx_process_weight_after_loading(weight, is_conv=False):
if weight.device != torch.device("cpu"):
return weight
if not cpu_has_amx_support():
return weight
if is_conv:
return torch.ops.sgl_kernel.causal_conv1d_weight_pack(
weight.view(-1, weight.size(-1))
)
else:
return torch.ops.sgl_kernel.convert_weight_packed(weight)
# TODO: currently gemm kernel has the below requirements:
# OC: OC % TILE_N == 0 or OC < TILE_N, where TILE_N = 16
# IC: IC % TILE_K == 0, where TILE_K = 32
def dim_is_supported(weight):
TILE_N = 16
TILE_K = 32
ndim = weight.ndim
OC = weight.size(1) if ndim == 3 else weight.size(0)
IC = weight.size(2) if ndim == 3 else weight.size(1)
is_oc_support = OC < TILE_N or OC % TILE_N == 0
is_ic_support = IC % TILE_K == 0
return is_oc_support and is_ic_support
def dtype_is_supported(weight):
return weight.dtype in [
torch.float16,
torch.bfloat16,
torch.int8,
torch.float8_e4m3fn,
]
def is_dim_conv_weight(weight):
return weight.dim() == 3 and weight.size(1) == 1
def _init_amx_conv_state(conv_state):
# CPU AMX layout for conv_state kernel optimization
conv_state_cpu = []
for conv_shape_t in conv_state:
conv_shape_new = conv_shape_t.as_strided_(
conv_shape_t.size(),
(
conv_shape_t.stride(0),
conv_shape_t.stride(1),
1,
conv_shape_t.size(2),
),
)
conv_state_cpu.append(conv_shape_new)
return conv_state_cpu
def _amx_process_weight_after_loading(
module, weight_names, transpose_dims=None
) -> None:
# Pack weight for get better performance on CPU
devices = {getattr(module, weight_name).device for weight_name in weight_names}
assert len(devices) == 1, f"Expects all weights to be on the same device"
device = devices.pop()
if transpose_dims:
assert len(weight_names) == len(
transpose_dims
), "len(weight_names) should be equal to len(transpose_dims)"
for i, weight_name in enumerate(weight_names):
weight_tensor = getattr(module, weight_name)
if transpose_dims and transpose_dims[i]:
weight_tensor = weight_tensor.transpose(*transpose_dims[i])
is_conv_weight = is_dim_conv_weight(weight_tensor)
# We don't pack weight or use intel amx backend if any weight of this module has unsupported dim.
if (
(not dim_is_supported(weight_tensor))
or not dtype_is_supported(weight_tensor)
) and (not is_conv_weight):
logger.warning(
f"Unsupported dimension or dtype for prepacking for weight '{weight_name}' with shape {weight_tensor.shape} and dtype {weight_tensor.dtype} in {module}. "
f"The derived (OC, IC) dimensions must be divisible by (16, 32). "
)
module.use_intel_amx_backend = False
return
packed_weight = torch.nn.Parameter(
amx_process_weight_after_loading(weight_tensor, is_conv_weight),
requires_grad=False,
)
packed_weight.__dict__ = weight_tensor.__dict__
setattr(module, weight_name, packed_weight)
if is_conv_weight:
# need to use inplace copy for conv weight amx packing,
# as its usage in radix_linear_attention will use the original conv weight.
weight_tensor = weight_tensor.view(-1, weight_tensor.size(-1))
weight_tensor.copy_(packed_weight)
module.use_intel_amx_backend = (
device == torch.device("cpu") and cpu_has_amx_support()
)
if (
module.use_intel_amx_backend
and hasattr(module, "bias")
and module.bias is not None
):
module.bias = torch.nn.Parameter(module.bias.data.float(), requires_grad=False)
class PackWeightMethod:
def __init__(self, weight_names, transpose_dims=None):
self.weight_names = weight_names
self.transpose_dims = transpose_dims
def process_weights_after_loading(self, module) -> None:
_amx_process_weight_after_loading(
module, self.weight_names, self.transpose_dims
)