[Performance] Fused blockwise quant RMS norm (#27883)

Signed-off-by: ElizaWszola <ewszola@redhat.com>
Signed-off-by: yewentao256 <zhyanwentao@126.com>
Co-authored-by: yewentao256 <zhyanwentao@126.com>
This commit is contained in:
ElizaWszola
2025-12-07 17:38:04 +01:00
committed by GitHub
parent 0044c4038c
commit af0444bf40
14 changed files with 949 additions and 157 deletions

View File

@@ -18,6 +18,9 @@ from vllm.config import (
VllmConfig,
)
from vllm.model_executor.layers.layernorm import RMSNorm
from vllm.model_executor.layers.quantization.utils.fp8_utils import (
W8A8BlockFp8LinearOp,
)
from vllm.model_executor.layers.quantization.utils.quant_utils import (
GroupShape,
QuantKey,
@@ -25,10 +28,12 @@ from vllm.model_executor.layers.quantization.utils.quant_utils import (
)
from vllm.model_executor.layers.quantization.utils.w8a8_utils import (
Fp8LinearOp,
cutlass_block_fp8_supported,
cutlass_fp8_supported,
maybe_create_device_identity,
)
from vllm.platforms import current_platform
from vllm.utils.deep_gemm import is_deep_gemm_supported
from ..utils import override_cutlass_fp8_supported
from .backend import TestBackend
@@ -44,7 +49,7 @@ class TestModel(torch.nn.Module):
self,
hidden_size: int,
eps: float,
static: bool,
group_shape: GroupShape,
cuda_force_torch: bool,
*args,
**kwargs,
@@ -52,8 +57,17 @@ class TestModel(torch.nn.Module):
super().__init__(*args, **kwargs)
self.cuda_force_torch = cuda_force_torch
self.norm = [RMSNorm(hidden_size, eps) for _ in range(4)]
self.wscale = [torch.rand(1, dtype=torch.float32) for _ in range(3)]
group_shape = GroupShape.PER_TENSOR if static else GroupShape.PER_TOKEN
if group_shape.is_per_group():
self.wscale = [
torch.rand(
(hidden_size // group_shape[1], hidden_size // group_shape[1]),
dtype=torch.float32,
)
for _ in range(3)
]
else:
self.wscale = [torch.rand(1, dtype=torch.float32) for _ in range(3)]
static = group_shape == GroupShape.PER_TENSOR
quant_scale = ScaleDesc(torch.float32, static, group_shape)
self.quant_key = QuantKey(dtype=FP8_DTYPE, scale=quant_scale, symmetric=True)
if static:
@@ -61,18 +75,29 @@ class TestModel(torch.nn.Module):
else:
self.scale = [None for _ in range(3)]
self.w = [
torch.rand(hidden_size, hidden_size).to(dtype=FP8_DTYPE).t()
for _ in range(3)
torch.rand(hidden_size, hidden_size).to(dtype=FP8_DTYPE) for _ in range(3)
]
if not group_shape.is_per_group():
self.w = [self.w[0].t() for _ in range(3)]
with override_cutlass_fp8_supported(not cuda_force_torch):
self.fp8_linear = Fp8LinearOp(
act_quant_static=static,
if group_shape.is_per_group():
self.fp8_linear = W8A8BlockFp8LinearOp(
weight_group_shape=GroupShape(group_shape[1], group_shape[1]),
act_quant_group_shape=group_shape,
cutlass_block_fp8_supported=cutlass_block_fp8_supported(),
use_aiter_and_is_supported=False,
)
self.enable_quant_fp8_custom_op = self.fp8_linear.input_quant_op.enabled()
else:
with override_cutlass_fp8_supported(not cuda_force_torch):
self.fp8_linear = Fp8LinearOp(
act_quant_static=static,
act_quant_group_shape=group_shape,
)
self.enable_quant_fp8_custom_op = self.fp8_linear.quant_fp8.enabled()
self.enable_rms_norm_custom_op = self.norm[0].enabled()
self.enable_quant_fp8_custom_op = self.fp8_linear.quant_fp8.enabled()
self.group_shape = group_shape
def forward(self, x):
# avoid having graph input be an arg to a pattern directly
@@ -119,11 +144,19 @@ class TestModel(torch.nn.Module):
)
GROUP_SHAPES = [
GroupShape.PER_TOKEN,
GroupShape.PER_TENSOR,
GroupShape(1, 128),
GroupShape(1, 64),
]
@pytest.mark.parametrize("dtype", [torch.float16, torch.bfloat16])
@pytest.mark.parametrize("hidden_size", [64])
@pytest.mark.parametrize("hidden_size", [256])
@pytest.mark.parametrize("num_tokens", [257])
@pytest.mark.parametrize("eps", [1e-5, 1e-6])
@pytest.mark.parametrize("static", [True, False])
@pytest.mark.parametrize("group_shape", GROUP_SHAPES)
@pytest.mark.parametrize("enable_rms_norm_custom_op", [True, False])
@pytest.mark.parametrize("enable_quant_fp8_custom_op", [True, False])
# cuda_force_torch used to test torch code path on platforms that
@@ -139,7 +172,7 @@ def test_fusion_rmsnorm_quant(
hidden_size,
num_tokens,
eps,
static,
group_shape,
enable_rms_norm_custom_op,
enable_quant_fp8_custom_op,
cuda_force_torch,
@@ -149,6 +182,15 @@ def test_fusion_rmsnorm_quant(
torch.manual_seed(1)
maybe_create_device_identity() # needed for certain non-cutlass fp8 paths
if not enable_quant_fp8_custom_op and group_shape.is_per_group():
pytest.skip("Unsupported unwrapped quant fp8 op for blockwise quantization")
# Skip test for 64-bit group shape when running with cutlass or deepgemm
if group_shape == GroupShape(1, 64) and (
cutlass_block_fp8_supported() or is_deep_gemm_supported()
):
pytest.skip("Unsupported group shape 64 for CUTLASS/DeepGemm")
custom_ops = []
if enable_rms_norm_custom_op:
custom_ops.append("+rms_norm")
@@ -172,8 +214,7 @@ def test_fusion_rmsnorm_quant(
backend = TestBackend(noop_pass, fusion_pass, cleanup_pass)
backend2 = TestBackend(noop_pass, cleanup_pass)
model = TestModel(hidden_size, eps, static, cuda_force_torch)
model = TestModel(hidden_size, eps, group_shape, cuda_force_torch)
# First dimension dynamic
x = torch.rand(num_tokens, hidden_size)
torch._dynamo.mark_dynamic(x, 0)

View File

@@ -8,6 +8,12 @@ import torch
import vllm._custom_ops as ops
from tests.kernels.utils import opcheck
from vllm.model_executor.layers.layernorm import RMSNorm
from vllm.model_executor.layers.quantization.utils.fp8_utils import (
per_token_group_quant_fp8,
)
from vllm.model_executor.layers.quantization.utils.int8_utils import (
per_token_group_quant_int8,
)
DTYPES = [torch.bfloat16, torch.float]
QUANT_DTYPES = [torch.int8, torch.float8_e4m3fn]
@@ -21,6 +27,7 @@ NUM_TOKENS_HIDDEN_SIZES = [
ADD_RESIDUAL = [False, True]
SCALE_UBS = [True, False]
GROUP_SIZES = [None, [1, 64], [1, 128]]
SEEDS = [0]
CUDA_DEVICES = [f"cuda:{i}" for i in range(1 if torch.cuda.device_count() == 1 else 2)]
@@ -45,12 +52,13 @@ def ref_rms_norm(
return out, residual
def ref_dynamic_per_token_quant(
def ref_dynamic_per_token_or_block_quant(
rms_norm_layer: RMSNorm,
x: torch.Tensor,
quant_dtype: torch.dtype,
residual: torch.Tensor | None,
scale_ub: torch.Tensor | None,
group_size: list[int] | None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor | None]:
if scale_ub is not None:
assert quant_dtype == torch.float8_e4m3fn
@@ -59,13 +67,24 @@ def ref_dynamic_per_token_quant(
torch_out, residual = ref_rms_norm(rms_norm_layer, x, residual)
# Quant
if quant_dtype == torch.float8_e4m3fn:
torch_out, scales = ops.scaled_fp8_quant(
torch_out, scale_ub=scale_ub, use_per_token_if_dynamic=True
)
if group_size is not None:
if quant_dtype == torch.float8_e4m3fn:
torch_out, scales = per_token_group_quant_fp8(
torch_out, group_size=group_size[1], use_ue8m0=False
)
else:
assert quant_dtype == torch.int8
torch_out, scales = per_token_group_quant_int8(
torch_out, group_size=group_size[1]
)
else:
assert quant_dtype == torch.int8
torch_out, scales, _ = ops.scaled_int8_quant(torch_out)
if quant_dtype == torch.float8_e4m3fn:
torch_out, scales = ops.scaled_fp8_quant(
torch_out, scale_ub=scale_ub, use_per_token_if_dynamic=True
)
else:
assert quant_dtype == torch.int8
torch_out, scales, _ = ops.scaled_int8_quant(torch_out)
return torch_out, scales, residual
@@ -76,24 +95,32 @@ def ref_impl(
quant_dtype: torch.dtype,
residual: torch.Tensor | None,
scale_ub: torch.Tensor | None,
group_size: list[int] | None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor | None]:
return ref_dynamic_per_token_quant(
rms_norm_layer, x, quant_dtype, residual, scale_ub
return ref_dynamic_per_token_or_block_quant(
rms_norm_layer, x, quant_dtype, residual, scale_ub, group_size
)
def ops_dynamic_per_token_quant(
def ops_dynamic_per_token_or_block_quant(
weight: torch.Tensor,
x: torch.Tensor,
quant_dtype: torch.dtype,
residual: torch.Tensor | None,
scale_ub: torch.Tensor | None,
group_size: list[int] | None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor | None]:
if residual is not None:
residual = residual.clone()
out, scales = ops.rms_norm_dynamic_per_token_quant(
x, weight, EPS, quant_dtype, scale_ub, residual
)
if group_size is not None:
out, scales = ops.rms_norm_per_block_quant(
x, weight, EPS, quant_dtype, group_size, scale_ub, residual, True
)
scales = scales.contiguous()
else:
out, scales = ops.rms_norm_dynamic_per_token_quant(
x, weight, EPS, quant_dtype, scale_ub, residual
)
return out, scales, residual
@@ -103,8 +130,11 @@ def ops_impl(
quant_dtype: torch.dtype,
residual: torch.Tensor | None,
scale_ub: torch.Tensor | None,
group_size: list[int] | None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor | None]:
return ops_dynamic_per_token_quant(weight, x, quant_dtype, residual, scale_ub)
return ops_dynamic_per_token_or_block_quant(
weight, x, quant_dtype, residual, scale_ub, group_size
)
@pytest.mark.parametrize("num_tokens, hidden_size", NUM_TOKENS_HIDDEN_SIZES)
@@ -112,6 +142,7 @@ def ops_impl(
@pytest.mark.parametrize("has_scale_ub", SCALE_UBS)
@pytest.mark.parametrize("dtype", DTYPES)
@pytest.mark.parametrize("quant_dtype", QUANT_DTYPES)
@pytest.mark.parametrize("group_size", GROUP_SIZES)
@pytest.mark.parametrize("seed", SEEDS)
@pytest.mark.parametrize("device", CUDA_DEVICES)
@torch.inference_mode()
@@ -122,6 +153,7 @@ def test_rms_norm(
has_scale_ub: bool,
dtype: torch.dtype,
quant_dtype: torch.dtype,
group_size: list[int] | None,
seed: int,
device: str,
) -> None:
@@ -130,6 +162,14 @@ def test_rms_norm(
torch.cuda.manual_seed(seed)
torch.set_default_device(device)
if group_size is not None and hidden_size % group_size[1] != 0:
# skip
return
if group_size is not None and has_scale_ub:
# blockwise baseline doesn't support scale_ub
return
if has_scale_ub and quant_dtype != torch.float8_e4m3fn:
# skip
return
@@ -150,10 +190,10 @@ def test_rms_norm(
scale_ub = None
ref_out, ref_scales, ref_residual = ref_impl(
layer, x, quant_dtype, residual, scale_ub
layer, x, quant_dtype, residual, scale_ub, group_size
)
ops_out, ops_scales, ops_residual = ops_impl(
layer.weight, x, quant_dtype, residual, scale_ub
layer.weight, x, quant_dtype, residual, scale_ub, group_size
)
assert ref_out.dtype == quant_dtype
@@ -166,11 +206,15 @@ def test_rms_norm(
assert torch.allclose(ref_scales, ops_scales)
a = ref_out.to(dtype=torch.float32)
b = ops_out.to(dtype=torch.float32)
ok = torch.allclose(a, b)
ok = torch.allclose(a, b, atol=1e-6)
if not ok:
# fallback: compare dequantized values with relaxed tolerance
a_deq = a * ref_scales.view(-1, 1)
b_deq = b * ops_scales.view(-1, 1)
if group_size is None:
a_deq = a * ref_scales.view(-1, 1)
b_deq = b * ops_scales.view(-1, 1)
else:
a_deq = a * ref_scales.repeat_interleave(group_size[1], dim=1)
b_deq = b * ops_scales.repeat_interleave(group_size[1], dim=1)
# NOTE: It is possible that some future test cases trigger this
# max diff due to precision issues. If such an error is
# encountered, it's recommended to inspect the differences between