[FIX] Add NO_MUL activation support for modular kernel path (#31528)

Signed-off-by: dafrimi <dafrimi@nvidia.com>
Signed-off-by: <>
Co-authored-by: root <root@gpu-267.slurm-workers-slurm.slurm.svc.cluster.local>
Co-authored-by: root <root@gpu-537.slurm-workers-slurm.slurm.svc.cluster.local>
Co-authored-by: Michael Goin <mgoin64@gmail.com>
Co-authored-by: root <root@pool0-01777.cm.cluster>

tests/kernels/moe/test_triton_moe_no_act_mul.py

+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""Tests for MoE with non-gated activations (*_no_mul).
+
+These tests verify that MoE layers work correctly with activations like
+silu_no_mul, gelu_no_mul, relu2_no_mul where the activation output dimension
+equals N (not N // 2 like gated activations).
+"""
+
+import pytest
+import torch
+
+from vllm.model_executor.layers.fused_moe.config import (
+    FUSED_MOE_UNQUANTIZED_CONFIG,
+)
+from vllm.model_executor.layers.fused_moe.fused_moe import TritonExperts
+from vllm.model_executor.layers.fused_moe.utils import (
+    GELU_NO_MUL,
+    RELU2_NO_MUL,
+    SILU_NO_MUL,
+)
+from vllm.platforms import current_platform
+
+# Test parameters
+M_SIZES = [1, 16, 64]
+N_SIZES = [128, 256]
+K_SIZES = [64, 128]
+TOPK_VALUES = [1, 2]
+NUM_EXPERTS = 8
+NO_MUL_ACTIVATIONS = [SILU_NO_MUL, GELU_NO_MUL, RELU2_NO_MUL]
+
+
+def make_test_tensors(
+    m: int,
+    n: int,
+    k: int,
+    num_experts: int,
+    topk: int,
+    dtype: torch.dtype = torch.bfloat16,
+    device: str = "cuda",
+):
+    """Create test tensors for MoE with non-gated activation.
+
+    For non-gated activations (*_no_mul):
+    - w1: (E, N, K) - projects from K to N
+    - w2: (E, K, N) - projects from N back to K (note: N, not N//2)
+    """
+    hidden_states = torch.randn(m, k, dtype=dtype, device=device)
+
+    # For non-gated: w1 projects K -> N, w2 projects N -> K
+    w1 = torch.randn(num_experts, n, k, dtype=dtype, device=device) * 0.1
+    w2 = torch.randn(num_experts, k, n, dtype=dtype, device=device) * 0.1
+
+    topk_weights = torch.ones(m, topk, dtype=torch.float32, device=device) / topk
+    topk_ids = torch.randint(0, num_experts, (m, topk), device=device)
+
+    return hidden_states, w1, w2, topk_weights, topk_ids
+
+
+@pytest.mark.skipif(
+    not current_platform.has_device_capability(80),
+    reason="Requires compute capability >= 8.0",
+)
+@pytest.mark.parametrize("m", M_SIZES)
+@pytest.mark.parametrize("n", N_SIZES)
+@pytest.mark.parametrize("k", K_SIZES)
+@pytest.mark.parametrize("topk", TOPK_VALUES)
+@pytest.mark.parametrize("activation", NO_MUL_ACTIVATIONS)
+@torch.inference_mode()
+def test_triton_experts_no_mul_activation(
+    m: int,
+    n: int,
+    k: int,
+    topk: int,
+    activation: str,
+):
+    hidden_states, w1, w2, topk_weights, topk_ids = make_test_tensors(
+        m, n, k, NUM_EXPERTS, topk
+    )
+
+    experts = TritonExperts(FUSED_MOE_UNQUANTIZED_CONFIG)
+
+    ws1_shape, ws2_shape, out_shape = experts.workspace_shapes(
+        M=m,
+        N=n,
+        K=k,
+        topk=topk,
+        global_num_experts=NUM_EXPERTS,
+        local_num_experts=NUM_EXPERTS,
+        expert_tokens_meta=None,
+        activation=activation,
+    )
+
+    # Verify workspace shapes are correct for no_mul activation
+    # workspace1 should handle activation_out_dim = N (not N//2)
+    assert ws1_shape == (m, topk, max(n, k)), (
+        f"workspace1 shape mismatch: expected {(m, topk, max(n, k))}, got {ws1_shape}"
+    )
+    # workspace2 should handle max(N, K) for intermediate_cache1/cache3
+    assert ws2_shape == (m, topk, max(n, k)), (
+        f"workspace2 shape mismatch: expected {(m, topk, max(n, k))}, got {ws2_shape}"
+    )
+    assert out_shape == (m, k), (
+        f"output shape mismatch: expected {(m, k)}, got {out_shape}"
+    )
+
+    workspace1 = torch.empty(
+        ws1_shape[0] * ws1_shape[1] * ws1_shape[2],
+        dtype=hidden_states.dtype,
+        device=hidden_states.device,
+    )
+    workspace2 = torch.empty(
+        ws2_shape[0] * ws2_shape[1] * ws2_shape[2],
+        dtype=hidden_states.dtype,
+        device=hidden_states.device,
+    )
+    output = torch.zeros(m, k, dtype=hidden_states.dtype, device=hidden_states.device)
+
+    experts.apply(
+        output=output,
+        hidden_states=hidden_states,
+        w1=w1,
+        w2=w2,
+        topk_weights=topk_weights,
+        topk_ids=topk_ids,
+        activation=activation,
+        global_num_experts=NUM_EXPERTS,
+        expert_map=None,
+        a1q_scale=None,
+        a2_scale=None,
+        workspace13=workspace1,
+        workspace2=workspace2,
+        expert_tokens_meta=None,
+        apply_router_weight_on_input=False,
+    )
+
+    assert output.shape == (m, k), f"Expected shape {(m, k)}, got {output.shape}"
+    assert not torch.isnan(output).any(), "Output contains NaN"
+    assert not torch.isinf(output).any(), "Output contains Inf"
+    assert output.abs().sum() > 0, "Output is all zeros"
+
+
+@pytest.mark.skipif(
+    not current_platform.has_device_capability(80),
+    reason="Requires compute capability >= 8.0",
+)
+@torch.inference_mode()
+def test_workspace_shapes_no_mul_vs_gated():
+    """Test that workspace shapes differ correctly between gated and non-gated."""
+    from vllm.model_executor.layers.fused_moe.fused_moe import TritonExperts
+
+    M, N, K, topk = 64, 256, 128, 2
+
+    experts = TritonExperts(FUSED_MOE_UNQUANTIZED_CONFIG)
+
+    ws1_no_mul, _, out_no_mul = experts.workspace_shapes(
+        M, N, K, topk, 8, 8, None, SILU_NO_MUL
+    )
+
+    ws1_gated, _, out_gated = experts.workspace_shapes(
+        M, N, K, topk, 8, 8, None, "silu"
+    )
+
+    # For no_mul: activation_out_dim = N
+    # For gated: activation_out_dim = N // 2
+    # workspace1 should use max(activation_out_dim, K)
+    activation_out_dim_no_mul = N
+    activation_out_dim_gated = N // 2
+
+    assert ws1_no_mul[2] == max(activation_out_dim_no_mul, K), (
+        f"no_mul workspace1 last dim should be max({activation_out_dim_no_mul}, {K})"
+    )
+    assert ws1_gated[2] == max(activation_out_dim_gated, K), (
+        f"gated workspace1 last dim should be max({activation_out_dim_gated}, {K})"
+    )
+
+    # Output shapes should be the same
+    assert out_no_mul == out_gated == (M, K)
+
+
+@pytest.mark.skipif(
+    not current_platform.has_device_capability(80),
+    reason="Requires compute capability >= 8.0",
+)
+@torch.inference_mode()
+def test_adjust_n_for_activation():
+    """Test the adjust_N_for_activation method."""
+    from vllm.model_executor.layers.fused_moe.fused_moe import TritonExperts
+
+    experts = TritonExperts(FUSED_MOE_UNQUANTIZED_CONFIG)
+
+    N = 256
+
+    # Gated activations should return N // 2
+    assert experts.adjust_N_for_activation(N, "silu") == N // 2
+    assert experts.adjust_N_for_activation(N, "gelu") == N // 2
+
+    # Non-gated activations should return N
+    assert experts.adjust_N_for_activation(N, SILU_NO_MUL) == N
+    assert experts.adjust_N_for_activation(N, GELU_NO_MUL) == N
+    assert experts.adjust_N_for_activation(N, RELU2_NO_MUL) == N

vllm/model_executor/layers/fused_moe/batched_deep_gemm_moe.py

@@ -305,6 +305,7 @@ class BatchedDeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # FIXME (varun): We should be able to dispatch only from the leader
         # DP ranks in the case of TP > 1. At the moment, all the Ranks
@@ -312,8 +313,9 @@ class BatchedDeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
         num_dispatchers = self.num_dispatchers
         num_experts = local_num_experts
         max_num_tokens = M if self.max_num_tokens is None else self.max_num_tokens
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         workspace13 = (num_experts, max_num_tokens * num_dispatchers, max(K, N))
-        workspace2 = (num_experts, max_num_tokens * num_dispatchers, (N // 2))
+        workspace2 = (num_experts, max_num_tokens * num_dispatchers, activation_out_dim)
         output = (num_experts, max_num_tokens * num_dispatchers, K)
         return (workspace13, workspace2, output)
 

vllm/model_executor/layers/fused_moe/cutlass_moe.py

@@ -355,9 +355,11 @@ class CutlassExpertsFp8(CutlassExpertsFp8Base):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         workspace1 = (M * topk, max(N, K))
-        workspace2 = (M * topk, max(N // 2, K))
+        workspace2 = (M * topk, max(activation_out_dim, K))
         output = (M, K)
         return (workspace1, workspace2, output)
 
@@ -402,11 +404,17 @@ class CutlassBatchedExpertsFp8(CutlassExpertsFp8Base):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         num_dp = self.num_dispatchers
         assert num_dp is not None
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         workspace1 = (self.max_experts_per_worker, M * num_dp, max(N, K))
-        workspace2 = (self.max_experts_per_worker, M * num_dp, max(N // 2, K))
+        workspace2 = (
+            self.max_experts_per_worker,
+            M * num_dp,
+            max(activation_out_dim, K),
+        )
         output = (self.max_experts_per_worker, M, K)
         return (workspace1, workspace2, output)
 
@@ -635,13 +643,15 @@ class CutlassExpertsFp4(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         workspace1: tuple[int, ...] = ()
         workspace2: tuple[int, ...] = ()
         output: tuple[int, ...] = ()
         if self.use_batched_format:
             workspace1 = (self.max_experts_per_worker, M, max(N, K))
-            workspace2 = (self.max_experts_per_worker, M, (N // 2))
+            workspace2 = (self.max_experts_per_worker, M, activation_out_dim)
             output = (self.max_experts_per_worker, M, K)
         else:
             workspace1 = (M * topk, max(2 * N, K))
@@ -896,9 +906,11 @@ class CutlassExpertsW4A8Fp8(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         workspace1 = (M * topk, max(N, K))
-        workspace2 = (M * topk, max(N // 2, K))
+        workspace2 = (M * topk, max(activation_out_dim, K))
         output = (M, K)
         return (workspace1, workspace2, output)
 

vllm/model_executor/layers/fused_moe/deep_gemm_moe.py

@@ -143,6 +143,7 @@ class DeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         assert self.block_shape is not None
         block_m = self.block_shape[0]
@@ -151,7 +152,8 @@ class DeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
         )
         assert M_sum % block_m == 0
 
-        workspace1 = (M_sum, max(N // 2, K))
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
+        workspace1 = (M_sum, max(activation_out_dim, K))
         workspace2 = (M_sum, max(N, K))
         output = (M, K)
         return (workspace1, workspace2, output)
@@ -163,11 +165,13 @@ class DeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
         block_k = self.block_shape[1]
         scale_fmt = DeepGemmQuantScaleFMT.from_oracle()
 
+        M_sum, N = input.size()
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
+
         # 1. DeepGemm UE8M0: use packed per-token-group quant
         if scale_fmt == DeepGemmQuantScaleFMT.UE8M0:
-            M_sum, N = input.size()
             act_out = torch.empty(
-                (M_sum, N // 2), dtype=input.dtype, device=input.device
+                (M_sum, activation_out_dim), dtype=input.dtype, device=input.device
             )
             self.activation(activation, act_out, input)
             a2q, a2q_scale = per_token_group_quant_fp8_packed_for_deepgemm(
@@ -187,8 +191,9 @@ class DeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
             )
 
         # 3. fallback path for non-SiLU activations in non‑UE8M0 cases.
-        M_sum, N = input.size()
-        act_out = torch.empty((M_sum, N // 2), dtype=input.dtype, device=input.device)
+        act_out = torch.empty(
+            (M_sum, activation_out_dim), dtype=input.dtype, device=input.device
+        )
         self.activation(activation, act_out, input)
         return per_token_group_quant_fp8(
             act_out, block_k, column_major_scales=True, out_q=output
@@ -254,8 +259,9 @@ class DeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
             (a1q, a1q_scale), (w1, self.w1_scale), mm1_out, expert_ids
         )
 
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         quant_out = _resize_cache(
-            workspace13.view(dtype=torch.float8_e4m3fn), (M_sum, N // 2)
+            workspace13.view(dtype=torch.float8_e4m3fn), (M_sum, activation_out_dim)
         )
         a2q, a2q_scale = self._act_mul_quant(
             input=mm1_out.view(-1, N), output=quant_out, activation=activation

vllm/model_executor/layers/fused_moe/fallback.py

@@ -76,6 +76,7 @@ class FallbackExperts(mk.FusedMoEPermuteExpertsUnpermute, ABC):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         raise NotImplementedError
 

vllm/model_executor/layers/fused_moe/flashinfer_cutedsl_moe.py

@@ -91,6 +91,7 @@ class FlashInferCuteDSLExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # We use global_num_experts due to how moe_align_block_size handles
         # expert_maps.

vllm/model_executor/layers/fused_moe/flashinfer_cutlass_moe.py

@@ -103,6 +103,7 @@ class FlashInferExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # We use global_num_experts due to how moe_align_block_size handles
         # expert_maps.

vllm/model_executor/layers/fused_moe/fused_batched_moe.py

@@ -673,6 +673,7 @@ class NaiveBatchedExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         num_dp = self.num_dispatchers
         num_experts = local_num_experts
@@ -867,12 +868,14 @@ class BatchedTritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         num_dp = self.num_dispatchers
         num_experts = local_num_experts
         max_num_tokens = self.max_num_tokens
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         workspace13 = (num_experts, max_num_tokens * num_dp, max(K, N))
-        workspace2 = (num_experts, max_num_tokens * num_dp, (N // 2))
+        workspace2 = (num_experts, max_num_tokens * num_dp, activation_out_dim)
         output = (num_experts, max_num_tokens * num_dp, K)
         return (workspace13, workspace2, output)
 
@@ -947,7 +950,10 @@ class BatchedTritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
         # We can reuse the memory between these because by the time we need
         # cache3, we're done with cache1
         intermediate_cache1 = _resize_cache(workspace13, (E, max_num_tokens, N))
-        intermediate_cache2 = _resize_cache(workspace2, (E, max_num_tokens, N // 2))
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
+        intermediate_cache2 = _resize_cache(
+            workspace2, (E, max_num_tokens, activation_out_dim)
+        )
 
         # TODO(bnell): should this be done for any quantized type?
         if self.quant_config.use_fp8_w8a8:
@@ -978,7 +984,7 @@ class BatchedTritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
         # TODO (bnell): use triton utility from batched deep gemm.
         self.activation(
             activation,
-            intermediate_cache2.view(-1, N // 2),
+            intermediate_cache2.view(-1, activation_out_dim),
             intermediate_cache1.view(-1, N),
         )
 

vllm/model_executor/layers/fused_moe/fused_marlin_moe.py

@@ -640,6 +640,7 @@ class MarlinExperts(MarlinExpertsBase):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # Modular Kernel provisions output buffer from workspace1. However in
         # the fused_marlin_moe() function, the final torch.sum(), is defined
@@ -768,6 +769,7 @@ class BatchedMarlinExperts(MarlinExpertsBase):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         num_dispatchers = self.num_dispatchers
         num_experts = local_num_experts

vllm/model_executor/layers/fused_moe/fused_moe.py

@@ -9,7 +9,6 @@ from collections.abc import Callable
 from typing import Any
 
 import torch
-import torch.nn.functional as F
 
 import vllm.envs as envs
 import vllm.model_executor.layers.fused_moe.modular_kernel as mk
@@ -43,7 +42,7 @@ from vllm.model_executor.layers.fused_moe.topk_weight_and_reduce import (
 )
 from vllm.model_executor.layers.fused_moe.utils import (
     _resize_cache,
-    activation_without_mul,
+    apply_moe_activation,
     disable_inplace,
     moe_kernel_quantize_input,
 )
@@ -1957,11 +1956,6 @@ def fused_experts(
         )
 
 
-SILU_NO_MUL: str = activation_without_mul("silu")
-GELU_NO_MUL: str = activation_without_mul("gelu")
-RELU2_NO_MUL: str = activation_without_mul("relu2")
-
-
 def _get_config_quant_dtype(
     use_fp8_w8a8: bool,
     use_int8_w8a8: bool,
@@ -2094,8 +2088,13 @@ def fused_experts_impl(
     intermediate_cache3 = cache13[: M * top_k_num * K].view(M, top_k_num, K)
 
     # This needs separate memory since it's used concurrently with cache1
+    activation_out_dim = mk.FusedMoEPermuteExpertsUnpermute.adjust_N_for_activation(
+        N, activation
+    )
     intermediate_cache2 = torch.empty(
-        (M * top_k_num, N // 2), device=hidden_states.device, dtype=hidden_states.dtype
+        (M * top_k_num, activation_out_dim),
+        device=hidden_states.device,
+        dtype=hidden_states.dtype,
     )
 
     if hidden_states.dtype == torch.bfloat16:
@@ -2235,29 +2234,9 @@ def fused_experts_impl(
             B_bias=w1_bias,
         )
 
-        # Activation function with multiplication
-        if activation == "silu":
-            torch.ops._C.silu_and_mul(
-                intermediate_cache2, intermediate_cache1.view(-1, N)
-            )
-        elif activation == "gelu":
-            torch.ops._C.gelu_and_mul(
-                intermediate_cache2, intermediate_cache1.view(-1, N)
-            )
-        elif activation == "swigluoai":
-            # alpha = 1.702, limit = 7.0
-            torch.ops._C.swigluoai_and_mul(
-                intermediate_cache2, intermediate_cache1.view(-1, N)
+        apply_moe_activation(
+            activation, intermediate_cache2, intermediate_cache1.view(-1, N)
         )
-        # Activation function without multiplication
-        elif activation == SILU_NO_MUL:
-            intermediate_cache2 = F.silu(intermediate_cache1.view(-1, N))
-        elif activation == GELU_NO_MUL:
-            intermediate_cache2 = F.gelu(intermediate_cache1.view(-1, N))
-        elif activation == RELU2_NO_MUL:
-            intermediate_cache2 = torch.square(F.relu(intermediate_cache1.view(-1, N)))
-        else:
-            raise ValueError(f"Unsupported FusedMoe activation: {activation}.")
 
         qintermediate_cache2, a2q_scale = moe_kernel_quantize_input(
             A=intermediate_cache2,
@@ -2336,8 +2315,10 @@ class TritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
-        workspace1 = (M, topk, max(N // 2, K))
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
+        workspace1 = (M, topk, max(activation_out_dim, K))
         workspace2 = (M, topk, max(N, K))
         output = (M, K)
         return (workspace1, workspace2, output)
@@ -2412,8 +2393,9 @@ class TritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
 
         # Note that the output tensor might be in workspace1
         intermediate_cache1 = _resize_cache(workspace2, (num_tokens, top_k_num, N))
+        cache2_dim = self.adjust_N_for_activation(N, activation)
         intermediate_cache2 = _resize_cache(
-            workspace13, (num_tokens * top_k_num, N // 2)
+            workspace13, (num_tokens * top_k_num, cache2_dim)
         )
         intermediate_cache3 = _resize_cache(workspace2, (num_tokens, top_k_num, K))
 
@@ -2565,8 +2547,9 @@ class TritonWNA16Experts(TritonExperts):
 
         # Note that the output tensor might be in workspace1
         intermediate_cache1 = _resize_cache(workspace2, (num_tokens, top_k_num, N))
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         intermediate_cache2 = _resize_cache(
-            workspace13, (num_tokens * top_k_num, N // 2)
+            workspace13, (num_tokens * top_k_num, activation_out_dim)
         )
         intermediate_cache3 = _resize_cache(workspace2, (num_tokens, top_k_num, K))
 

vllm/model_executor/layers/fused_moe/gpt_oss_triton_kernels_moe.py

@@ -323,10 +323,12 @@ class OAITritonExperts(BaseOAITritonExperts):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # workspace are allocated inside the kernel
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
         workspace1 = (0, 0)
-        workspace2 = (M * topk, N // 2)
+        workspace2 = (M * topk, activation_out_dim)
         output = (M, K)
         return (workspace1, workspace2, output)
 
@@ -415,9 +417,11 @@ class UnfusedOAITritonExperts(BaseOAITritonExperts):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # workspace are allocated inside the kernel
-        workspace1 = (M * topk, N // 2)
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
+        workspace1 = (M * topk, activation_out_dim)
         workspace2 = (M * topk, max(N, K))
         output = (M, K)
         return (workspace1, workspace2, output)
@@ -443,8 +447,10 @@ class UnfusedOAITritonExperts(BaseOAITritonExperts):
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
         apply_router_weight_on_input: bool,
     ):
-        if self.quant_config is None:
-            self.quant_config = FUSED_MOE_UNQUANTIZED_CONFIG
+        # Use local variable to help mypy narrow the type after None check
+        quant_config = self.quant_config
+        if quant_config is None:
+            quant_config = FUSED_MOE_UNQUANTIZED_CONFIG
 
         if expert_map is not None:
             topk_ids = expert_map[topk_ids]
@@ -462,12 +468,10 @@ class UnfusedOAITritonExperts(BaseOAITritonExperts):
         # type check, uint8 means mxfp4
         assert hidden_states.dtype == torch.bfloat16
         assert (
-            self.quant_config.w1_bias is None
-            or self.quant_config.w1_bias.dtype == torch.float32
+            quant_config.w1_bias is None or quant_config.w1_bias.dtype == torch.float32
         )
         assert (
-            self.quant_config.w2_bias is None
-            or self.quant_config.w2_bias.dtype == torch.float32
+            quant_config.w2_bias is None or quant_config.w2_bias.dtype == torch.float32
         )
 
         # Shape check, only check non-mxfp4
@@ -485,17 +489,18 @@ class UnfusedOAITritonExperts(BaseOAITritonExperts):
         # Note that the output tensor might be in workspace13
         intermediate_cache1 = _resize_cache(workspace2, (batch_dim, M * topk, N))
         intermediate_cache3 = _resize_cache(workspace2, (batch_dim, M * topk, K))
-        intermediate_cache2 = _resize_cache(workspace13, (M * topk, N // 2))
+        activation_out_dim = self.adjust_N_for_activation(N, activation)
+        intermediate_cache2 = _resize_cache(workspace13, (M * topk, activation_out_dim))
 
         gammas = routing_data.gate_scal if routing_data else None
 
         matmul_ogs(
             hidden_states,
             w1,
-            self.quant_config.w1_bias,
+            quant_config.w1_bias,
             routing_data,
             gather_indx=gather_indx,
-            precision_config=self.quant_config.w1_precision,
+            precision_config=quant_config.w1_precision,
             gammas=gammas if apply_router_weight_on_input else None,
             fused_activation=None,
             y=intermediate_cache1,
@@ -515,10 +520,10 @@ class UnfusedOAITritonExperts(BaseOAITritonExperts):
         matmul_ogs(
             intermediate_cache2[gather_indx.src_indx],
             w2,
-            self.quant_config.w2_bias,
+            quant_config.w2_bias,
             routing_data,
             scatter_indx=scatter_indx,
-            precision_config=self.quant_config.w2_precision,
+            precision_config=quant_config.w2_precision,
             gammas=None if apply_router_weight_on_input else gammas,
             y=intermediate_cache3,
         )

vllm/model_executor/layers/fused_moe/modular_kernel.py

@@ -18,6 +18,7 @@ from vllm.model_executor.layers.fused_moe.config import (
 )
 from vllm.model_executor.layers.fused_moe.utils import (
     _resize_cache,
+    apply_moe_activation,
     count_expert_num_tokens,
     disable_inplace,
 )
@@ -542,6 +543,7 @@ class FusedMoEPermuteExpertsUnpermute(ABC):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         """
         Compute the shapes for the temporary and final outputs of the two gemms
@@ -572,19 +574,31 @@ class FusedMoEPermuteExpertsUnpermute(ABC):
         """
         raise NotImplementedError
 
+    @staticmethod
+    def adjust_N_for_activation(N: int, activation: str) -> int:
+        """
+        Calculate the output dimension for the activation function.
+
+        For *_no_mul activations (e.g. relu2_no_mul),
+        there's no gate/up split, so output size equals input size (N).
+
+        For regular gated activations (e.g., silu, gelu, swigluoai),
+        output size is N // 2 due to gate × activation(up) multiplication.
+
+        Args:
+            N: The intermediate size (width of w1/w3 weights).
+            activation: The activation function name.
+
+        Returns:
+            The output dimension after activation.
+        """
+        is_no_mul = activation.endswith("_no_mul")
+        return N if is_no_mul else N // 2
+
     def activation(
         self, activation: str, output: torch.Tensor, input: torch.Tensor
     ) -> None:
-        assert output.size(-1) * 2 == input.size(-1)
-        if activation == "silu":
-            torch.ops._C.silu_and_mul(output, input)
-        elif activation == "gelu":
-            torch.ops._C.gelu_and_mul(output, input)
-        elif activation == "swigluoai":
-            # alpha = 1.702, limit = 7.0
-            torch.ops._C.swigluoai_and_mul(output, input)
-        else:
-            raise ValueError(f"Unsupported FusedMoe activation: {activation}")
+        apply_moe_activation(activation, output, input)
 
     def enable_chunking(self):
         return (
@@ -761,6 +775,7 @@ class FusedMoEModularKernel(torch.nn.Module):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
         """
         Allocate temporary and output buffers for the fused experts op.
@@ -796,6 +811,7 @@ class FusedMoEModularKernel(torch.nn.Module):
                     # amount of workspace. Mark it None, so we allocate for
                     # the worst-case scenario.
                     expert_tokens_meta=None,
+                    activation=activation,
                 )
             )
 
@@ -814,6 +830,7 @@ class FusedMoEModularKernel(torch.nn.Module):
             global_num_experts,
             local_num_experts,
             expert_tokens_meta,
+            activation,
         )
 
         # Get final output shape based on the full M size.
@@ -825,6 +842,7 @@ class FusedMoEModularKernel(torch.nn.Module):
             global_num_experts,
             local_num_experts,
             expert_tokens_meta,
+            activation,
         )
 
         # We can reuse the memory between cache1 and cache3 because by the
@@ -1043,6 +1061,7 @@ class FusedMoEModularKernel(torch.nn.Module):
                 global_num_experts,
                 local_num_experts,
                 expert_tokens_meta,
+                activation,
             )
 
         for chunk_idx in range(num_chunks):

vllm/model_executor/layers/fused_moe/rocm_aiter_fused_moe.py

@@ -299,6 +299,7 @@ class AiterExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # Workspaces are managed internally by AITER.
         workspace1 = (0,)

vllm/model_executor/layers/fused_moe/triton_cutlass_moe.py

@@ -39,6 +39,7 @@ class TritonOrCutlassExperts(FallbackExperts):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # Small batch fallback for sm100.
         if self.is_sm100 and M <= 8:
@@ -50,6 +51,7 @@ class TritonOrCutlassExperts(FallbackExperts):
                 global_num_experts,
                 local_num_experts,
                 expert_tokens_meta,
+                activation,
             )
         else:
             return self.experts.workspace_shapes(
@@ -60,6 +62,7 @@ class TritonOrCutlassExperts(FallbackExperts):
                 global_num_experts,
                 local_num_experts,
                 expert_tokens_meta,
+                activation,
             )
 
     def _select_experts_impl(

vllm/model_executor/layers/fused_moe/triton_deep_gemm_moe.py

@@ -35,6 +35,7 @@ class TritonOrDeepGemmExperts(FallbackExperts):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # Note: the deep gemm workspaces are strictly larger than the triton
         # workspaces so we can be pessimistic here and allocate for DeepGemm
@@ -48,6 +49,7 @@ class TritonOrDeepGemmExperts(FallbackExperts):
                 global_num_experts,
                 local_num_experts,
                 expert_tokens_meta,
+                activation,
             )
         else:
             return self.fallback_experts.workspace_shapes(
@@ -58,6 +60,7 @@ class TritonOrDeepGemmExperts(FallbackExperts):
                 global_num_experts,
                 local_num_experts,
                 expert_tokens_meta,
+                activation,
             )
 
     def _select_experts_impl(

vllm/model_executor/layers/fused_moe/trtllm_moe.py

@@ -57,6 +57,7 @@ class TrtLlmGenExperts(mk.FusedMoEPermuteExpertsUnpermute):
         global_num_experts: int,
         local_num_experts: int,
         expert_tokens_meta: mk.ExpertTokensMetadata | None,
+        activation: str,
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...]]:
         # The workspaces for this implementation are managed by flashinfer.
         workspace1 = (0,)

vllm/model_executor/layers/fused_moe/utils.py

@@ -4,6 +4,7 @@ import functools
 from math import prod
 
 import torch
+import torch.nn.functional as F
 
 from vllm import _custom_ops as ops
 from vllm.model_executor.layers.quantization.utils.fp8_utils import (
@@ -324,6 +325,55 @@ def activation_without_mul(activation: str) -> str:
     return activation + "_no_mul"
 
 
+RELU2_NO_MUL: str = activation_without_mul("relu2")
+SILU_NO_MUL: str = activation_without_mul("silu")
+GELU_NO_MUL: str = activation_without_mul("gelu")
+
+
+def apply_moe_activation(
+    activation: str,
+    output: torch.Tensor,
+    input: torch.Tensor,
+) -> torch.Tensor:
+    """
+    Apply MoE activation function.
+
+    For *_and_mul activations (silu, gelu, swigluoai):
+        - Expects output.size(-1) * 2 == input.size(-1)
+
+    For *_no_mul activations (silu_no_mul, gelu_no_mul, relu2_no_mul):
+        - Expects output.size(-1) == input.size(-1)
+    """
+    is_no_mul = activation.endswith("_no_mul")
+    if is_no_mul:
+        assert output.size(-1) == input.size(-1), (
+            f"{activation} expects equal sizes: {output.size(-1)} vs {input.size(-1)}"
+        )
+    else:
+        assert output.size(-1) * 2 == input.size(-1), (
+            f"{activation} expects 2x ratio: {output.size(-1) * 2} vs {input.size(-1)}"
+        )
+
+    # Activations with gated multiplication (gate × activation(up))
+    if activation == "silu":
+        torch.ops._C.silu_and_mul(output, input)
+    elif activation == "gelu":
+        torch.ops._C.gelu_and_mul(output, input)
+    elif activation == "swigluoai":
+        torch.ops._C.swigluoai_and_mul(output, input)
+    # Activations without gated multiplication
+    elif activation == SILU_NO_MUL:
+        output.copy_(F.silu(input))
+    elif activation == GELU_NO_MUL:
+        output.copy_(F.gelu(input))
+    elif activation == RELU2_NO_MUL:
+        torch.square(F.relu(input), out=output)
+    else:
+        raise ValueError(f"Unsupported FusedMoe activation: {activation}")
+
+    return output
+
+
 # Torch custom ops can't deal with outputs aliasing inputs so we need to
 # disable inplace for torch >= 2.9.
 # See https://github.com/vllm-project/vllm/issues/26378