Fix RoutingMethodType logic (#33919)

Signed-off-by: Dimitrios Bariamis <12195802+dbari@users.noreply.github.com>
Signed-off-by: mgoin <mgoin64@gmail.com>
Co-authored-by: Dimitrios Bariamis <12195802+dbari@users.noreply.github.com>
Co-authored-by: mgoin <mgoin64@gmail.com>

vllm/model_executor/layers/fused_moe/config.py

@@ -124,6 +124,23 @@ class RoutingMethodType(IntEnum):
     Unspecified = 8.0
 
 
+def get_routing_method_type(
+    scoring_func: str, top_k: int, renormalize: bool
+) -> RoutingMethodType:
+    if scoring_func == "sigmoid":
+        if top_k == 1:
+            return RoutingMethodType.Llama4
+        else:
+            return RoutingMethodType.DeepSeekV3
+    elif scoring_func == "softmax":
+        if renormalize:
+            return RoutingMethodType.Renormalize
+        else:
+            return RoutingMethodType.Default
+    else:
+        return RoutingMethodType.Unspecified
+
+
 @dataclass
 class FusedMoEQuantDesc:
     """

vllm/model_executor/layers/fused_moe/flashinfer_trtllm_moe.py

@@ -61,6 +61,8 @@ def _supports_routing_method(
     routing_method: RoutingMethodType,
 ) -> bool:
     """Monolithic kernels need to express router support."""
+    # NOTE(dbari): TopK routing could also be enabled, but need to validate models
+    # NOTE(dbari): Default is not implemented and should not be enabled until it is
     if (weight_key, activation_key) == (kFp8Static128BlockSym, kFp8Dynamic128Sym):
         # NOTE(rob): potentially allow others here. This is a conservative list.
         return routing_method in [
@@ -72,10 +74,8 @@ def _supports_routing_method(
         # NOTE(dbari): as above, potentially allow others here.
         return routing_method in [
             RoutingMethodType.Llama4,
-            # NOTE(mgoin): Disabled to investigate accuracy issues.
-            # See https://github.com/vllm-project/vllm/issues/33532
-            # RoutingMethodType.Renormalize,
-            # RoutingMethodType.RenormalizeNaive,
+            RoutingMethodType.Renormalize,
+            RoutingMethodType.RenormalizeNaive,
         ]
     else:
         raise ValueError("Unsupported quantization scheme.")
@@ -302,6 +302,8 @@ def fi_trtllm_fp8_per_tensor_moe(
         per_act_token_quant=False,
     )
 
+    from flashinfer.fused_moe.core import ActivationType
+
     from vllm.utils.flashinfer import flashinfer_trtllm_fp8_per_tensor_scale_moe
 
     return flashinfer_trtllm_fp8_per_tensor_scale_moe(
@@ -323,6 +325,9 @@ def fi_trtllm_fp8_per_tensor_moe(
         routed_scaling_factor=routed_scaling_factor,
         use_routing_scales_on_input=use_routing_scales_on_input,
         routing_method_type=routing_method_type,
+        # TODO: Required for flashinfer==0.6.3, remove with update
+        # https://github.com/flashinfer-ai/flashinfer/pull/2508
+        activation_type=ActivationType.Swiglu,
     )
 
 

vllm/model_executor/layers/fused_moe/router/fused_topk_bias_router.py

@@ -10,7 +10,10 @@ from vllm.distributed.eplb.eplb_state import EplbLayerState
 from vllm.model_executor.layers.batch_invariant import (
     vllm_is_batch_invariant,
 )
-from vllm.model_executor.layers.fused_moe.config import RoutingMethodType
+from vllm.model_executor.layers.fused_moe.config import (
+    RoutingMethodType,
+    get_routing_method_type,
+)
 from vllm.model_executor.layers.fused_moe.router.base_router import BaseRouter
 
 
@@ -158,10 +161,10 @@ class FusedTopKBiasRouter(BaseRouter):
 
     @property
     def routing_method_type(self) -> RoutingMethodType:
-        return (
-            RoutingMethodType.Renormalize
-            if not self.renormalize
-            else RoutingMethodType.RenormalizeNaive
+        return get_routing_method_type(
+            scoring_func=self.scoring_func,
+            top_k=self.top_k,
+            renormalize=self.renormalize,
         )
 
     def _compute_routing(

vllm/model_executor/layers/fused_moe/router/fused_topk_router.py

@@ -7,7 +7,10 @@ import torch
 import vllm._custom_ops as ops
 from vllm._aiter_ops import rocm_aiter_ops
 from vllm.distributed.eplb.eplb_state import EplbLayerState
-from vllm.model_executor.layers.fused_moe.config import RoutingMethodType
+from vllm.model_executor.layers.fused_moe.config import (
+    RoutingMethodType,
+    get_routing_method_type,
+)
 from vllm.model_executor.layers.fused_moe.router.base_router import BaseRouter
 
 
@@ -135,10 +138,10 @@ class FusedTopKRouter(BaseRouter):
 
     @property
     def routing_method_type(self) -> RoutingMethodType:
-        return (
-            RoutingMethodType.Renormalize
-            if not self.renormalize
-            else RoutingMethodType.RenormalizeNaive
+        return get_routing_method_type(
+            scoring_func=self.scoring_func,
+            top_k=self.top_k,
+            renormalize=self.renormalize,
         )
 
     def _compute_routing(

vllm/model_executor/layers/fused_moe/router/router_factory.py

@@ -6,6 +6,7 @@ import torch
 
 import vllm.envs as envs
 from vllm.distributed.eplb.eplb_state import EplbLayerState
+from vllm.model_executor.layers.fused_moe.config import RoutingMethodType
 from vllm.model_executor.layers.fused_moe.router.custom_routing_router import (
     CustomRoutingRouter,
 )
@@ -106,7 +107,7 @@ def create_fused_moe_router(
                 "num_expert_group and topk_group must be provided when "
                 "use_grouped_topk is True"
             )
-        return GroupedTopKRouter(
+        grouped_topk_router = GroupedTopKRouter(
             top_k=top_k,
             global_num_experts=global_num_experts,
             eplb_state=eplb_state,
@@ -120,6 +121,18 @@ def create_fused_moe_router(
             enable_eplb=enable_eplb,
             indices_type_getter=indices_type_getter,
         )
+        if (
+            grouped_topk_router.routing_method_type != RoutingMethodType.Unspecified
+            or num_expert_group > 1
+            or topk_group > 1
+        ):
+            return grouped_topk_router
+
+        # If routing_method for GroupedTopKRouter is Unspecified and there is only
+        # one group, fallback to standard top-k routing
+        use_grouped_topk = False
+        num_expert_group = None
+        topk_group = None
 
     if custom_routing_function is not None:
         return CustomRoutingRouter(