439 lines
15 KiB
Python

import enum
from enum import Enum
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,
set_weight_attrs)
from vllm.model_executor.layers.quantization.base_config import (
QuantizationConfig)
GPTQ_MARLIN_TILE = 16
GPTQ_MARLIN_MIN_THREAD_N = 64
GPTQ_MARLIN_MIN_THREAD_K = 128
GPTQ_MARLIN_MAX_PARALLEL = 16
GPTQ_MARLIN_SUPPORTED_NUM_BITS = [4, 8]
GPTQ_MARLIN_SUPPORTED_GROUP_SIZES = [-1, 32, 64, 128]
GPTQ_MARLIN_SUPPORTED_SYM = [True]
# Permutations for Marlin scale shuffling
def get_scale_perms(num_bits):
scale_perm = []
for i in range(8):
scale_perm.extend([i + 8 * j for j in range(8)])
scale_perm_single = []
for i in range(4):
scale_perm_single.extend(
[2 * i + j for j in [0, 1, 8, 9, 16, 17, 24, 25]])
return scale_perm, scale_perm_single
def get_pack_factor(num_bits):
assert (num_bits in GPTQ_MARLIN_SUPPORTED_NUM_BITS
), f"Unsupported num_bits = {num_bits}"
return 32 // num_bits
def marlin_permute_scales(s, size_k, size_n, group_size, num_bits):
scale_perm, scale_perm_single = get_scale_perms(num_bits)
if group_size < size_k and group_size != -1:
s = s.reshape((-1, len(scale_perm)))[:, scale_perm]
else:
s = s.reshape((-1, len(scale_perm_single)))[:, scale_perm_single]
s = s.reshape((-1, size_n)).contiguous()
return s
class GPTQMarlinConfig(QuantizationConfig):
"""Config class for GPTQ Marlin"""
def __init__(self, weight_bits: int, group_size: int, desc_act: bool,
is_sym: bool) -> None:
if desc_act and group_size == -1:
# In this case, act_order == True is the same as act_order == False
# (since we have only one group per output channel)
desc_act = False
self.weight_bits = weight_bits
self.group_size = group_size
self.desc_act = desc_act
self.is_sym = is_sym
# Verify
if self.weight_bits not in GPTQ_MARLIN_SUPPORTED_NUM_BITS:
raise ValueError(
f"Marlin does not support weight_bits = {self.weight_bits}. "
f"Only weight_bits = {GPTQ_MARLIN_SUPPORTED_NUM_BITS} "
"are supported.")
if self.group_size not in GPTQ_MARLIN_SUPPORTED_GROUP_SIZES:
raise ValueError(
f"Marlin does not support group_size = {self.group_size}. "
f"Only group_sizes = {GPTQ_MARLIN_SUPPORTED_GROUP_SIZES} "
"are supported.")
if self.is_sym not in GPTQ_MARLIN_SUPPORTED_SYM:
raise ValueError(
f"Marlin does not support is_sym = {self.is_sym}. "
f"Only sym = {GPTQ_MARLIN_SUPPORTED_SYM} are supported.")
# Init
self.pack_factor = get_pack_factor(weight_bits)
self.tile_size = GPTQ_MARLIN_TILE
self.min_thread_n = GPTQ_MARLIN_MIN_THREAD_N
self.min_thread_k = GPTQ_MARLIN_MIN_THREAD_K
self.max_parallel = GPTQ_MARLIN_MAX_PARALLEL
def __repr__(self) -> str:
return (f"GPTQMarlinConfig(weight_bits={self.weight_bits}, "
f"group_size={self.group_size}, "
f"desc_act={self.desc_act})")
@classmethod
def get_name(cls) -> str:
return "gptq_marlin"
@classmethod
def get_supported_act_dtypes(cls) -> List[torch.dtype]:
return [torch.half, torch.bfloat16]
@classmethod
def get_min_capability(cls) -> int:
return 80
@classmethod
def get_config_filenames(cls) -> List[str]:
return ["quantize_config.json"]
@classmethod
def from_config(cls, config: Dict[str, Any]) -> "GPTQMarlinConfig":
weight_bits = cls.get_from_keys(config, ["bits"])
group_size = cls.get_from_keys(config, ["group_size"])
desc_act = cls.get_from_keys(config, ["desc_act"])
is_sym = cls.get_from_keys(config, ["sym"])
return cls(weight_bits, group_size, desc_act, is_sym)
def get_quant_method(
self,
layer: torch.nn.Module) -> Optional["GPTQMarlinLinearMethod"]:
if isinstance(layer, LinearBase):
return GPTQMarlinLinearMethod(self)
return None
def get_scaled_act_names(self) -> List[str]:
return []
@classmethod
def is_marlin_compatible(cls, quant_config: Dict[str, Any]):
# Extract data from quant config.
num_bits = quant_config.get("bits", None)
group_size = quant_config.get("group_size", None)
sym = quant_config.get("sym", None)
desc_act = quant_config.get("desc_act", None)
# If we cannot find the info needed in the config, cannot convert.
if (num_bits is None or group_size is None or sym is None
or desc_act is None):
return False
# If the capability of the device is too low, cannot convert.
major, minor = torch.cuda.get_device_capability()
device_capability = major * 10 + minor
if device_capability < cls.get_min_capability():
return False
# Otherwise, can convert if model satisfies marlin constraints.
return (num_bits in GPTQ_MARLIN_SUPPORTED_NUM_BITS
and group_size in GPTQ_MARLIN_SUPPORTED_GROUP_SIZES
and sym in GPTQ_MARLIN_SUPPORTED_SYM)
class GPTQMarlinState(Enum):
REPACK = enum.auto()
READY = enum.auto()
class GPTQMarlinLinearMethod(LinearMethodBase):
"""Linear method for GPTQ Marlin.
Args:
quant_config: The GPTQ Marlin quantization config.
"""
def __init__(self, quant_config: GPTQMarlinConfig) -> None:
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,
) -> None:
del output_size
# Normalize group_size
if self.quant_config.group_size != -1:
group_size = self.quant_config.group_size
else:
group_size = input_size
# Validate dtype
if params_dtype not in [torch.float16, torch.bfloat16]:
raise ValueError(f"The params dtype must be float16 "
f"or bfloat16, but got {params_dtype}")
# Validate output_size_per_partition
output_size_per_partition = sum(output_partition_sizes)
if output_size_per_partition % self.quant_config.min_thread_n != 0:
raise ValueError(
f"Weight output_size_per_partition = "
f"{output_size_per_partition} is not divisible by "
f" min_thread_n = {self.quant_config.min_thread_n}.")
# Validate input_size_per_partition
if input_size_per_partition % self.quant_config.min_thread_k != 0:
raise ValueError(
f"Weight input_size_per_partition = "
f"{input_size_per_partition} is not divisible "
f"by min_thread_k = {self.quant_config.min_thread_k}.")
if (group_size < input_size
and input_size_per_partition % group_size != 0):
raise ValueError(
f"Weight input_size_per_partition = {input_size_per_partition}"
f" is not divisible by group_size = {group_size}.")
# Detect sharding of scales/zp
# By default, no sharding over "input dim"
scales_and_zp_size = input_size // group_size
scales_and_zp_input_dim = None
if self.quant_config.desc_act:
# Act-order case
assert self.quant_config.group_size != -1
is_k_full = input_size_per_partition == input_size
else:
# No act-order case
# K is always full due to full alignment with
# group-size and shard of scales/zp
is_k_full = True
# If this is a row-parallel case, then shard scales/zp
if (input_size != input_size_per_partition
and self.quant_config.group_size != -1):
scales_and_zp_size = input_size_per_partition // group_size
scales_and_zp_input_dim = 0
# Init buffers
# Quantized weights
qweight = Parameter(
torch.empty(
input_size_per_partition // self.quant_config.pack_factor,
output_size_per_partition,
dtype=torch.int32,
),
requires_grad=False,
)
set_weight_attrs(
qweight,
{
**extra_weight_attrs,
"input_dim": 0,
"output_dim": 1,
"packed_dim": 0,
"pack_factor": self.quant_config.pack_factor,
},
)
# Activation order
g_idx = Parameter(
torch.empty(
input_size_per_partition,
dtype=torch.int32,
),
requires_grad=False,
)
# Ignore warning from fused linear layers such as QKVParallelLinear.
set_weight_attrs(
g_idx,
{
**extra_weight_attrs, "input_dim": 0,
"ignore_warning": True
},
)
g_idx_sort_indices = Parameter(
torch.empty(
g_idx.shape,
dtype=torch.int32,
),
requires_grad=False,
)
set_weight_attrs(g_idx_sort_indices, extra_weight_attrs)
# Scales
scales = Parameter(
torch.empty(
scales_and_zp_size,
output_size_per_partition,
dtype=params_dtype,
),
requires_grad=False,
)
set_weight_attrs(
scales,
{
**extra_weight_attrs,
"input_dim": scales_and_zp_input_dim,
"output_dim": 1,
},
)
# Quantized zero-points
qzeros = Parameter(
torch.empty(
scales_and_zp_size,
output_size_per_partition // self.quant_config.pack_factor,
dtype=torch.int32,
device="meta",
),
requires_grad=False,
)
set_weight_attrs(
qzeros,
{
**extra_weight_attrs,
"input_dim": scales_and_zp_input_dim,
"output_dim": 1,
"packed_dim": 1,
"pack_factor": self.quant_config.pack_factor,
},
)
# Allocate marlin workspace
max_workspace_size = (
output_size_per_partition //
self.quant_config.min_thread_n) * self.quant_config.max_parallel
workspace = torch.zeros(max_workspace_size,
dtype=torch.int,
requires_grad=False)
layer.register_parameter("qweight", qweight)
layer.register_parameter("g_idx", g_idx)
layer.register_parameter("g_idx_sort_indices", g_idx_sort_indices)
layer.register_parameter("scales", scales)
layer.register_parameter("qzeros", qzeros)
layer.workspace = workspace
layer.input_size_per_partition = input_size_per_partition
layer.output_size_per_partition = output_size_per_partition
layer.input_size = input_size
layer.is_k_full = is_k_full
layer.marlin_state = GPTQMarlinState.REPACK
def apply(
self,
layer: torch.nn.Module,
x: torch.Tensor,
bias: Optional[torch.Tensor] = None,
) -> torch.Tensor:
reshaped_x = x.reshape(-1, x.shape[-1])
size_m = reshaped_x.shape[0]
part_size_n = layer.output_size_per_partition
part_size_k = layer.input_size_per_partition
full_size_k = layer.input_size
out_shape = x.shape[:-1] + (part_size_n, )
if layer.marlin_state == GPTQMarlinState.REPACK:
layer.marlin_state = GPTQMarlinState.READY
# Newly generated tensors need to replace existing tensors that are
# already registered as parameters by vLLM (and won't be freed)
def replace_tensor(name, new_t):
# It is important to use resize_() here since it ensures
# the same buffer is reused
getattr(layer, name).resize_(new_t.shape)
getattr(layer, name).copy_(new_t)
del new_t
cur_device = layer.qweight.device
# Process act_order
if self.quant_config.desc_act:
# Get sorting based on g_idx
g_idx_sort_indices = torch.argsort(layer.g_idx).to(torch.int)
sorted_g_idx = layer.g_idx[g_idx_sort_indices]
replace_tensor("g_idx", sorted_g_idx)
replace_tensor("g_idx_sort_indices", g_idx_sort_indices)
else:
# Reset g_idx related tensors
layer.g_idx = Parameter(
torch.empty(0, dtype=torch.int, device=cur_device),
requires_grad=False,
)
layer.g_idx_sort_indices = Parameter(
torch.empty(0, dtype=torch.int, device=cur_device),
requires_grad=False,
)
# Repack weights
marlin_qweight = ops.gptq_marlin_repack(
layer.qweight,
layer.g_idx_sort_indices,
part_size_k,
part_size_n,
self.quant_config.weight_bits,
)
replace_tensor("qweight", marlin_qweight)
# Permute scales
scales_size_k = part_size_k
scales_size_n = part_size_n
if self.quant_config.desc_act:
scales_size_k = full_size_k
marlin_scales = marlin_permute_scales(
layer.scales,
scales_size_k,
scales_size_n,
self.quant_config.group_size,
self.quant_config.weight_bits,
)
replace_tensor("scales", marlin_scales)
output = ops.gptq_marlin_gemm(
reshaped_x,
layer.qweight,
layer.scales,
layer.g_idx,
layer.g_idx_sort_indices,
layer.workspace,
self.quant_config.weight_bits,
size_m,
part_size_n,
part_size_k,
layer.is_k_full,
)
if bias is not None:
output.add_(bias) # In-place add
return output.reshape(out_shape)