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sglang/python/sglang/srt/layers/torchao_utils.py
2026-01-22 22:04:51 -08:00

96 lines
2.9 KiB
Python

"""
Common utilities for torchao.
"""
import logging
from typing import Callable, Optional
import torch
logger = logging.getLogger(__name__)
def proj_filter(
module: torch.nn.Module,
fqn: str,
):
"""Filter function for quantizing projection layers."""
return "proj" in fqn
# TODO: implement a more general filter function
def proj_filter_conv3d(
module: torch.nn.Module,
fqn: str,
):
if isinstance(module, torch.nn.Conv3d):
logger.warning(f"Quantize: skipping {fqn} because it's a Conv3d")
return False
return "proj" in fqn
def apply_torchao_config_to_model(
model: torch.nn.Module,
torchao_config: str,
filter_fn: Optional[Callable] = proj_filter,
):
"""Quantize a modelwith torchao quantization specified by torchao_config
Args:
`model`: a model to be quantized based on torchao_config
`torchao_config` (str): type of quantization and their arguments we want to use to
quantize the model, e.g. int4wo-128 means int4 weight only quantization with group_size
128
"""
if torchao_config == "" or torchao_config is None:
return model
# Lazy import to suppress some warnings
from torchao.quantization import (
float8_dynamic_activation_float8_weight,
float8_weight_only,
int4_weight_only,
int8_dynamic_activation_int8_weight,
int8_weight_only,
quantize_,
)
from torchao.quantization.observer import PerRow, PerTensor
if "int8wo" in torchao_config:
quantize_(model, int8_weight_only(), filter_fn=proj_filter_conv3d)
elif "int8dq" in torchao_config:
quantize_(model, int8_dynamic_activation_int8_weight(), filter_fn=filter_fn)
elif "int4wo" in torchao_config:
group_size = int(torchao_config.split("-")[-1])
assert group_size in [
32,
64,
128,
256,
], f"int4wo groupsize needs to be one of [32, 64, 128, 256] but got {group_size}"
quantize_(model, int4_weight_only(group_size=group_size), filter_fn=filter_fn)
elif "fp8wo" in torchao_config:
# this requires newer hardware
# [rank0]: AssertionError: fp8e4nv data type is not supported on CUDA arch < 89
quantize_(model, float8_weight_only(), filter_fn=proj_filter_conv3d)
elif "fp8dq" in torchao_config:
granularity = torchao_config.split("-")[-1]
GRANULARITY_MAP = {
"per_row": PerRow(),
"per_tensor": PerTensor(),
}
assert (
granularity in GRANULARITY_MAP
), f"Supported granularity are: {GRANULARITY_MAP.keys()}, got {granularity}"
quantize_(
model,
float8_dynamic_activation_float8_weight(
granularity=GRANULARITY_MAP[granularity]
),
filter_fn=proj_filter_conv3d,
)
else:
raise ValueError(f"Unexpected config: {torchao_config}")
return model