[torch.compile] Enable silu_mul_fp8_quant fusion without custom ops enabled (vllm-project#27146)

ZJY0516 · 0xrushi · commit aaa47a611213 · 2025-10-25T23:00:01.000-04:00
Signed-off-by: zjy0516 &lt;riverclouds.zhu@qq.com&gt;
Signed-off-by: 0xrushi &lt;6279035+0xrushi@users.noreply.github.com&gt;
diff --git a/tests/compile/test_silu_mul_quant_fusion.py b/tests/compile/test_silu_mul_quant_fusion.py
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-from typing import cast
+import itertools
 
 import pytest
 import torch
@@ -16,7 +16,13 @@
 from vllm.compilation.fusion import QUANT_OPS
 from vllm.compilation.noop_elimination import NoOpEliminationPass
 from vllm.compilation.post_cleanup import PostCleanupPass
-from vllm.config import CompilationConfig, PassConfig, VllmConfig
+from vllm.config import (
+    CompilationConfig,
+    CompilationMode,
+    PassConfig,
+    VllmConfig,
+    set_current_vllm_config,
+)
 from vllm.model_executor.layers.activation import SiluAndMul
 from vllm.model_executor.layers.quantization.utils.quant_utils import (
     GroupShape,
@@ -25,7 +31,7 @@
 )
 from vllm.model_executor.layers.quantization.utils.w8a8_utils import (
     Fp8LinearOp,
-    cutlass_fp8_supported,
+    maybe_create_device_identity,
 )
 from vllm.platforms import current_platform
 
@@ -54,14 +60,23 @@ def __init__(self, hidden_size: int, cuda_force_torch: bool, **kwargs):
                 act_quant_static=True,
                 act_quant_group_shape=GroupShape.PER_TENSOR,
             )
+        self.enable_silu_mul_custom_op = self.silu_and_mul.enabled()
+        self.enable_quant_fp8_custom_op = self.fp8_linear.quant_fp8.enabled()
 
     def forward(self, x):
         y = self.silu_and_mul(x)
         x2 = self.fp8_linear.apply(y, self.w, self.wscale, input_scale=self.wscale)
         return x2
 
     def ops_in_model_before(self):
-        return [SILU_MUL_OP, QUANT_OPS[kFp8StaticTensorSym]]
+        return [
+            SILU_MUL_OP if self.enable_silu_mul_custom_op else torch.ops.aten.mul,
+            (
+                QUANT_OPS[kFp8StaticTensorSym]
+                if self.enable_quant_fp8_custom_op
+                else torch.ops.aten.reciprocal
+            ),
+        ]
 
     def ops_in_model_after(self):
         return [FUSED_OPS[kFp8StaticTensorSym]]
@@ -77,6 +92,7 @@ def __init__(self, hidden_size: int, x: torch.Tensor, **kwargs):
         assert silu_and_mul_nvfp4_quant_supported
 
         self.silu_and_mul = SiluAndMul()
+        self.enable_silu_mul_custom_op = self.silu_and_mul.enabled()
 
         # create nvfp4 weight
         w = torch.rand((hidden_size, hidden_size))
@@ -101,7 +117,10 @@ def forward(self, x):
         return out
 
     def ops_in_model_before(self):
-        return [SILU_MUL_OP, QUANT_OPS[kNvfp4Quant]]
+        return [
+            SILU_MUL_OP if self.enable_silu_mul_custom_op else torch.ops.aten.mul,
+            QUANT_OPS[kNvfp4Quant],
+        ]
 
     def ops_in_model_after(self):
         return [FUSED_OPS[kNvfp4Quant]]
@@ -110,67 +129,80 @@ def ops_in_model_after(self):
 @pytest.mark.parametrize("num_tokens", [32, 64])
 @pytest.mark.parametrize("hidden_size", [128, 256])
 @pytest.mark.parametrize("dtype", [torch.bfloat16, torch.float16])
+@pytest.mark.parametrize("enable_silu_mul_custom_op", [True, False])
 @pytest.mark.parametrize(
-    "model_class",
-    cast(
-        list[type],
-        [TestSiluMulFp8QuantModel, TestSiluMulNvfp4QuantModel]
-        if is_nvfp4_supported()
-        else [TestSiluMulFp8QuantModel],
-    ),
+    "model_class, enable_quant_fp8_custom_op, cuda_force_torch",
+    list(itertools.product([TestSiluMulFp8QuantModel], [True, False], [True, False]))
+    + [(TestSiluMulNvfp4QuantModel, False, False)],
 )
 # cuda_force_torch used to test torch code path on platforms that
 # cutlass_fp8_supported() == True.
-@pytest.mark.parametrize(
-    "cuda_force_torch", [True, False] if cutlass_fp8_supported() else [True]
-)
 @pytest.mark.skipif(
     envs.VLLM_TARGET_DEVICE not in ["cuda", "rocm"], reason="Only test on CUDA and ROCm"
 )
 def test_fusion_silu_and_mul_quant(
-    num_tokens, hidden_size, dtype, model_class, cuda_force_torch
+    num_tokens: int,
+    hidden_size: int,
+    dtype: torch.dtype,
+    model_class: type[TestSiluMulFp8QuantModel | TestSiluMulNvfp4QuantModel],
+    enable_silu_mul_custom_op: bool,
+    enable_quant_fp8_custom_op: bool,
+    cuda_force_torch: bool,
 ):
-    if model_class == TestSiluMulNvfp4QuantModel and cuda_force_torch:
-        pytest.skip("Duplicate tests for NVFP4")
+    if model_class is TestSiluMulNvfp4QuantModel and not is_nvfp4_supported():
+        pytest.skip("NVFP4 is not supported on this GPU.")
 
     torch.set_default_device("cuda")
     torch.set_default_dtype(dtype)
+    maybe_create_device_identity()
 
     x = torch.rand(num_tokens, hidden_size * 2)
 
     # Reshape pass is needed for the fusion pass to work
-    config = VllmConfig()
-    config.compilation_config = CompilationConfig(
-        pass_config=PassConfig(enable_fusion=True, enable_noop=True)
+    custom_ops = []
+    if enable_silu_mul_custom_op:
+        custom_ops.append("+silu_and_mul")
+    if enable_quant_fp8_custom_op:
+        custom_ops.append("+quant_fp8")
+    config = VllmConfig(
+        compilation_config=CompilationConfig(
+            mode=CompilationMode.VLLM_COMPILE,
+            custom_ops=custom_ops,
+            pass_config=PassConfig(enable_fusion=True, enable_noop=True),
+        ),
     )
-    fusion_pass = ActivationQuantFusionPass(config)
 
-    passes = [NoOpEliminationPass(config), fusion_pass, PostCleanupPass(config)]
-    backend = TestBackend(*passes)
-    model = model_class(hidden_size=hidden_size, cuda_force_torch=cuda_force_torch, x=x)
+    with set_current_vllm_config(config):
+        fusion_pass = ActivationQuantFusionPass(config)
 
-    # First dimension dynamic
-    torch._dynamo.mark_dynamic(x, 0)
+        passes = [NoOpEliminationPass(config), fusion_pass, PostCleanupPass(config)]
+        backend = TestBackend(*passes)
+        model = model_class(
+            hidden_size=hidden_size, cuda_force_torch=cuda_force_torch, x=x
+        )
 
-    result = model(x)
+        # First dimension dynamic
+        torch._dynamo.mark_dynamic(x, 0)
 
-    model2 = torch.compile(model, backend=backend)
-    result2 = model2(x)
+        result = model(x)
 
-    # Check that it gives the same answer
-    if model_class == TestSiluMulFp8QuantModel:
-        atol, rtol = 1e-3, 1e-3
-    elif model_class == TestSiluMulNvfp4QuantModel:
-        atol, rtol = 1e-1, 1e-1
+        model2 = torch.compile(model, backend=backend)
+        result2 = model2(x)
 
-    torch.testing.assert_close(
-        result[0].to(dtype=dtype), result2[0].to(dtype=dtype), atol=atol, rtol=rtol
-    )
+        # Check that it gives the same answer
+        if model_class == TestSiluMulFp8QuantModel:
+            atol, rtol = 1e-3, 1e-3
+        elif model_class == TestSiluMulNvfp4QuantModel:
+            atol, rtol = 1e-1, 1e-1
+
+        torch.testing.assert_close(
+            result[0].to(dtype=dtype), result2[0].to(dtype=dtype), atol=atol, rtol=rtol
+        )
 
-    assert fusion_pass.matched_count == 1
+        assert fusion_pass.matched_count == 1
 
-    # In pre-nodes, quant op should be present and fused kernels should not
-    backend.check_before_ops(model.ops_in_model_before())
+        # In pre-nodes, quant op should be present and fused kernels should not
+        backend.check_before_ops(model.ops_in_model_before())
 
-    # In post-nodes, fused kernels should be present and quant op should not
-    backend.check_after_ops(model.ops_in_model_after())
+        # In post-nodes, fused kernels should be present and quant op should not
+        backend.check_after_ops(model.ops_in_model_after())
diff --git a/vllm/compilation/activation_quant_fusion.py b/vllm/compilation/activation_quant_fusion.py
@@ -18,12 +18,12 @@
     QuantKey,
     kFp8StaticTensorSym,
     kNvfp4Quant,
-    kStaticTensorScale,
 )
 from vllm.platforms import current_platform
 
 from .fusion import QUANT_OPS, empty_bf16, empty_fp32, empty_i32
 from .inductor_pass import enable_fake_mode
+from .matcher_utils import MatcherQuantFP8, MatcherSiluAndMul
 from .vllm_inductor_pass import VllmInductorPass, VllmPatternMatcherPass
 
 logger = init_logger(__name__)
@@ -66,6 +66,8 @@ def __init__(
         )
         self.FUSED_OP = FUSED_OPS[self.quant_key]
 
+        self.silu_and_mul_matcher = MatcherSiluAndMul()
+
     def empty_quant(self, *args, **kwargs):
         kwargs = {"dtype": self.quant_dtype, "device": "cuda", **kwargs}
         return torch.empty(*args, **kwargs)
@@ -80,42 +82,38 @@ class SiluMulFp8StaticQuantPattern(ActivationQuantPattern):
     Fusion for SiluMul+Fp8StaticQuant Pattern
     """
 
-    def __init__(self, symmetric: bool = True):
-        quant_key = QuantKey(
-            dtype=FP8_DTYPE, scale=kStaticTensorScale, symmetric=symmetric
-        )
-        super().__init__(quant_key)
+    def __init__(self):
+        super().__init__(kFp8StaticTensorSym)
+        self.quant_matcher = MatcherQuantFP8(kFp8StaticTensorSym)
 
     def register(self, pm_pass: PatternMatcherPass):
         def pattern(
-            result: torch.Tensor,
-            result_silu_mul: torch.Tensor,
             input: torch.Tensor,
             scale: torch.Tensor,
         ):
-            at1 = auto_functionalized(SILU_MUL_OP, result=result_silu_mul, input=input)
-            at2 = auto_functionalized(
-                self.QUANT_OP, result=result, input=at1[1], scale=scale
-            )
-            return at2[1]
+            result_silu_mul = self.silu_and_mul_matcher(input)
+            result_quant = self.quant_matcher(result_silu_mul, scale)
+            return result_quant[0]
 
         def replacement(
-            result: torch.Tensor,
-            result_silu_mul: torch.Tensor,
             input: torch.Tensor,
             scale: torch.Tensor,
         ):
+            d = input.shape[-1] // 2
+            output_shape = input.shape[:-1] + (d,)
+            result = torch.empty(
+                output_shape, device=input.device, dtype=self.quant_dtype
+            )
             at = auto_functionalized(
                 self.FUSED_OP, result=result, input=input, scale=scale
             )
             return at[1]
 
         inputs = [
-            self.empty_quant(5, 4),  # result
-            empty_bf16(5, 4),  # result_silu_mul
-            empty_bf16(5, 4),  # input
-            empty_fp32(1, 1),  # scale
+            *self.silu_and_mul_matcher.inputs(),  # input
+            self.quant_matcher.inputs()[1],  # scale
         ]
+        pattern(*inputs)
 
         register_replacement(pattern, replacement, inputs, fwd_only, pm_pass)
 
@@ -132,24 +130,22 @@ def register(self, pm_pass: PatternMatcherPass):
         def pattern(
             result: torch.Tensor,
             output_scale: torch.Tensor,
-            result_silu_mul: torch.Tensor,
             input: torch.Tensor,
             scale: torch.Tensor,
         ):
-            at1 = auto_functionalized(SILU_MUL_OP, result=result_silu_mul, input=input)
-            at2 = auto_functionalized(
+            result_silu_mul = self.silu_and_mul_matcher(input)
+            at = auto_functionalized(
                 self.QUANT_OP,
                 output=result,
-                input=at1[1],
+                input=result_silu_mul,
                 output_scale=output_scale,
                 input_scale=scale,
             )
-            return at2[1], at2[2]
+            return at[1], at[2]
 
         def replacement(
             result: torch.Tensor,
             output_scale: torch.Tensor,
-            result_silu_mul: torch.Tensor,
             input: torch.Tensor,
             scale: torch.Tensor,
         ):
@@ -165,7 +161,6 @@ def replacement(
         inputs = [
             self.empty_quant(5, 32),  # result
             empty_i32(128, 4),  # output_scale
-            empty_bf16(5, 64),  # result_silu_mul
             empty_bf16(5, 64),  # input
             empty_fp32(1, 1),  # scale
         ]
diff --git a/vllm/compilation/matcher_utils.py b/vllm/compilation/matcher_utils.py
@@ -7,6 +7,7 @@
 from torch._ops import OpOverload
 
 from vllm.config import get_current_vllm_config
+from vllm.model_executor.layers.activation import SiluAndMul
 from vllm.model_executor.layers.layernorm import RMSNorm
 from vllm.model_executor.layers.quantization.input_quant_fp8 import QuantFP8
 from vllm.model_executor.layers.quantization.utils.quant_utils import (
@@ -31,6 +32,8 @@
 if current_platform.is_cuda() and hasattr(torch.ops._C, "scaled_fp4_quant"):
     QUANT_OPS[kNvfp4Quant] = torch.ops._C.scaled_fp4_quant.default  # noqa: E501
 
+SILU_MUL_OP = torch.ops._C.silu_and_mul.default
+
 
 class MatcherCustomOp(ABC):
     def __init__(self, enabled: bool):
@@ -206,3 +209,30 @@ def inputs(self) -> list[torch.Tensor]:
             return [input, self.empty_f32(1, 1)]
 
         return [input]
+
+
+class MatcherSiluAndMul(MatcherCustomOp):
+    def __init__(self, enabled: bool | None = None):
+        if enabled is None:
+            enabled = SiluAndMul.enabled()
+        super().__init__(enabled)
+
+    def inputs(self) -> list[torch.Tensor]:
+        input = self.empty(5, 4)
+        return [input]
+
+    def forward_custom(
+        self,
+        x: torch.Tensor,
+    ) -> torch.Tensor:
+        d = x.shape[-1] // 2
+        output_shape = x.shape[:-1] + (d,)
+        out = torch.empty(output_shape, dtype=x.dtype, device=x.device)
+        result = auto_functionalized(SILU_MUL_OP, result=out, input=x)
+        return result[1]
+
+    def forward_native(
+        self,
+        x: torch.Tensor,
+    ) -> torch.Tensor:
+        return SiluAndMul.forward_native(x)
diff --git a/vllm/model_executor/layers/activation.py b/vllm/model_executor/layers/activation.py
@@ -80,7 +80,8 @@ def __init__(self):
         elif current_platform.is_cpu():
             self._forward_method = self.forward_native
 
-    def forward_native(self, x: torch.Tensor) -> torch.Tensor:
+    @staticmethod
+    def forward_native(x: torch.Tensor) -> torch.Tensor:
         """PyTorch-native implementation equivalent to forward()."""
         d = x.shape[-1] // 2
         return F.silu(x[..., :d]) * x[..., d:]
