[DP/EP][GPTOSS] Use triton matmul-ogs kernels for GPTOSS DP/EP (#24588)

Signed-off-by: Varun Sundar Rabindranath <vsundarr@redhat.com>
Co-authored-by: Varun Sundar Rabindranath <vsundarr@redhat.com>

vllm/model_executor/layers/fused_moe/config.py

@@ -288,7 +288,11 @@ class FusedMoEQuantConfig:
 
     @property
     def use_mxfp4_w4a4(self) -> bool:
-        return self.quant_dtype == "mxfp4"
+        return (self._a1.dtype == "mxfp4" and self._w1.dtype == "mxfp4")
+
+    @property
+    def use_mxfp4_w4a16(self) -> bool:
+        return (self._a1.dtype is None and self._w1.dtype == "mxfp4")
 
     @property
     def use_nvfp4_w4a4(self) -> bool:
@@ -453,6 +457,22 @@ def int8_w8a8_moe_quant_config(
     )
 
 
+def mxfp4_w4a16_moe_quant_config(
+        w1_scale: Union[torch.Tensor, "PrecisionConfig"],
+        w2_scale: Union[torch.Tensor, "PrecisionConfig"],
+        w1_bias: Optional[torch.Tensor] = None,
+        w2_bias: Optional[torch.Tensor] = None) -> FusedMoEQuantConfig:
+    """
+    Construct a quant config for unquantized activations and mxfp4 weights.
+    """
+    return FusedMoEQuantConfig(
+        _a1=FusedMoEQuantDesc(),
+        _a2=FusedMoEQuantDesc(),
+        _w1=FusedMoEQuantDesc("mxfp4", None, w1_scale, None, None, w1_bias),
+        _w2=FusedMoEQuantDesc("mxfp4", None, w2_scale, None, None, w2_bias),
+    )
+
+
 def mxfp4_w4a4_moe_quant_config(
     w1_scale: Union[torch.Tensor, "PrecisionConfig"],
     w2_scale: Union[torch.Tensor, "PrecisionConfig"],

vllm/model_executor/layers/fused_moe/deepep_ht_prepare_finalize.py

@@ -11,6 +11,7 @@ from vllm.model_executor.layers.fused_moe.topk_weight_and_reduce import (
     TopKWeightAndReduceContiguous, TopKWeightAndReduceDelegate)
 from vllm.model_executor.layers.fused_moe.utils import (
     moe_kernel_quantize_input)
+from vllm.utils import round_up
 
 
 class DeepEPHTPrepareAndFinalize(mk.FusedMoEPrepareAndFinalize):
@@ -18,6 +19,23 @@ class DeepEPHTPrepareAndFinalize(mk.FusedMoEPrepareAndFinalize):
     Prepare/Finalize using DeepEP High-Throughput kernels.
     """
 
+    @staticmethod
+    def maybe_roundup_layer_hidden_size(hidden_size: int,
+                                        dtype: torch.dtype) -> int:
+        # Round up hidden size so it is compatible with DeepEP High Throughput
+        # kernels.
+        # DeepEP intranode kernels make copies in units of,
+        # 32(warp-size) int4 elements. Round up hidden size to respect this.
+        # For example, an input hidden size of 2880 with dtype torch.bfloat16
+        # will be rounded up to 3072.
+        hidden_size_bytes = hidden_size * dtype.itemsize
+        xfer_atom_size = 512  # 32 * 16 (size(int4))
+        if hidden_size_bytes % xfer_atom_size == 0:
+            return hidden_size
+
+        hidden_size_bytes = round_up(hidden_size_bytes, xfer_atom_size)
+        return hidden_size_bytes // dtype.itemsize
+
     def __init__(self, buffer: deep_ep.Buffer, num_dispatchers: int,
                  dp_size: int, rank_expert_offset: int):
         super().__init__()

vllm/model_executor/layers/fused_moe/gpt_oss_triton_kernels_moe.py

@@ -9,7 +9,8 @@ from vllm.logger import init_logger
 from vllm.model_executor.layers.fused_moe.config import (
     FUSED_MOE_UNQUANTIZED_CONFIG, FusedMoEQuantConfig)
 from vllm.model_executor.layers.fused_moe.topk_weight_and_reduce import (
-    TopKWeightAndReduceDelegate)
+    TopKWeightAndReduceNoOP)
+from vllm.triton_utils import tl, triton
 from vllm.utils import has_triton_kernels
 
 logger = init_logger(__name__)
@@ -19,13 +20,55 @@ if has_triton_kernels():
         import triton_kernels.swiglu
         from triton_kernels.matmul_ogs import (FnSpecs, FusedActivation,
                                                matmul_ogs)
-        from triton_kernels.routing import routing
+        from triton_kernels.routing import (RoutingData, routing,
+                                            routing_from_bitmatrix)
+        from triton_kernels.tensor import Bitmatrix
     except (ModuleNotFoundError, AttributeError) as e:
         logger.error(
             "Failed to import Triton kernels. Please make sure your triton "
             "version is compatible. Error: %s", e)
 
 
+@triton.jit
+def pack_bitmatrix(
+    bitmatrix,
+    topk_ids,
+    n_rows,  # n_rows in bitmatrix / topk_ids 
+    bm_cols: tl.constexpr,  # n int32_t bitpacks in bitmatrix
+    n_expts_act,  # num_topk 
+    BLOCK_SIZE_M: tl.constexpr,
+    BLOCK_SIZE_K: tl.constexpr,
+):
+    """
+    Packs topk_ids into a bitmatrix.
+    code reference:
+    https://github.com/triton-lang/triton/blob/dd1bbc52b34d202dfe5ffea1e04fb16166c5c04e/python/triton_kernels/bench/distributed.py#L264
+    """
+    pid_m = tl.program_id(0)
+    offsets_m = pid_m * BLOCK_SIZE_M + tl.arange(0, BLOCK_SIZE_M)
+    offsets_k = tl.arange(0, BLOCK_SIZE_K)
+    offsets = offsets_m[:, None] * n_expts_act + offsets_k[None, :]
+    mask = (offsets_m < n_rows)[:, None] & (offsets_k < n_expts_act)[None, :]
+    indices = tl.load(topk_ids + offsets, mask=mask, other=-1)
+    div = indices // 32
+    rem = indices % 32
+    one = tl.cast(1, tl.uint32)
+
+    # Iterate through all the relevant bitmatrix columns.
+    for i in range(bm_cols):
+        # When BLOCK_SIZE_K=32, offs is just the column index.
+        offs = tl.arange(0, BLOCK_SIZE_K // 32) + i * (BLOCK_SIZE_K // 32)
+        # All topks that need to go into this column has the correct bit set.
+        # Other bits are 0. x is a 2D tensor.
+        x = tl.where(div[:, :, None] == offs[None, None, :],
+                     (one << rem)[:, :, None], 0)
+        # Reduce x to get a single int32_t bitpack.
+        y = tl.reduce_or(x, axis=1)
+        bitmatrix_ptrs = bitmatrix + offsets_m[:,
+                                               None] * bm_cols + offs[None, :]
+        tl.store(bitmatrix_ptrs, y, mask=offsets_m[:, None] < n_rows)
+
+
 def triton_kernel_moe_forward(
     hidden_states: torch.Tensor,
     w1,  # Tensor or triton_kernels.Tensor
@@ -124,34 +167,88 @@ def triton_kernel_fused_experts(
     return intermediate_cache3
 
 
-class BatchedOAITritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
+def make_routing_data(
+    topk_ids: torch.Tensor,
+    topk_weights: torch.Tensor,
+    num_local_experts: int,
+) -> tuple["RoutingData", torch.Tensor, torch.Tensor]:
 
-    def __init__(
+    topk_ids = topk_ids.to(torch.int16)
-        self,
+    topk_weights = topk_weights.to(torch.bfloat16)
-        max_num_tokens: int,
+
-        num_dispatchers: int,
+    n_rows, num_topk = topk_ids.size()
-        quant_config: FusedMoEQuantConfig,
+
-    ):
+    BLOCK_SIZE_M = 512
+    BLOCK_SIZE_K = 32
+
+    bm_cols = triton.cdiv(num_local_experts, BLOCK_SIZE_K)  # n_bitpacks
+    bitmatrix = torch.zeros((n_rows, bm_cols),
+                            dtype=torch.uint32,
+                            device=topk_ids.device)
+
+    grid = (triton.cdiv(n_rows, BLOCK_SIZE_M), )
+    pack_bitmatrix[grid](
+        bitmatrix,
+        topk_ids,
+        n_rows,
+        bm_cols,
+        num_topk,
+        BLOCK_SIZE_M=BLOCK_SIZE_M,
+        BLOCK_SIZE_K=BLOCK_SIZE_K,
+    )
+
+    bitmatrix_shape = [n_rows, bm_cols * 32]
+    bitmatrix_shape_max = [n_rows, None]
+    bitmatrix = Bitmatrix(bitmatrix,
+                          shape=bitmatrix_shape,
+                          shape_max=bitmatrix_shape_max,
+                          scratchpad=None)
+
+    # matmul_ogs expects invalid topk_weights to be -1s
+    topk_weights = torch.where(topk_ids == -1, -1.0, topk_weights)
+    routing_data, gather_indx, scatter_indx = routing_from_bitmatrix(
+        bitmatrix, topk_weights, topk_ids, num_local_experts, num_topk)
+
+    return routing_data, gather_indx, scatter_indx
+
+
+class BaseOAITritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
+
+    def __init__(self, quant_config: FusedMoEQuantConfig):
+        super().__init__(quant_config)
+
+    def supports_expert_map(self) -> bool:
+        return True
+
+    def finalize_weight_and_reduce_impl(self) -> mk.TopKWeightAndReduce:
+        # Weight application and reduction happens in the fused_experts kernel.
+        return TopKWeightAndReduceNoOP()
+
+    def _make_routing_data(
+        self,
+        topk_ids: torch.Tensor,
+        topk_weights: torch.Tensor,
+        num_local_experts: int,
+    ) -> tuple["RoutingData", torch.Tensor, torch.Tensor]:
+        return make_routing_data(topk_ids, topk_weights, num_local_experts)
+
+
+class OAITritonExperts(BaseOAITritonExperts):
+
+    def __init__(self, quant_config: FusedMoEQuantConfig):
+        # TODO (varun) : Enable activation quantization
+        assert quant_config.use_mxfp4_w4a16, "Supports only mxfp4_w4a16"
         super().__init__(quant_config)
-        self.max_num_tokens = max_num_tokens
-        self.num_dispatchers = num_dispatchers
 
     @property
     def activation_formats(
         self
     ) -> tuple[mk.FusedMoEActivationFormat, mk.FusedMoEActivationFormat]:
-        return (mk.FusedMoEActivationFormat.BatchedExperts,
+        return (mk.FusedMoEActivationFormat.Standard,
-                mk.FusedMoEActivationFormat.BatchedExperts)
+                mk.FusedMoEActivationFormat.Standard)
 
     def supports_chunking(self) -> bool:
-        return False
+        return True
-
-    def supports_expert_map(self) -> bool:
-        return False
-
-    def finalize_weight_and_reduce_impl(self) -> mk.TopKWeightAndReduce:
-        # Let PrepareAndFinalize::finalize() decide the impl.
-        return TopKWeightAndReduceDelegate()
 
     def workspace_shapes(
         self, a: torch.Tensor, aq: torch.Tensor, M: int, N: int, K: int,
@@ -159,13 +256,10 @@ class BatchedOAITritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
         expert_tokens_meta: Optional[mk.ExpertTokensMetadata]
     ) -> tuple[tuple[int, ...], tuple[int, ...], tuple[int, ...], torch.dtype]:
         # workspace are allocated inside the kernel
-        assert a.dim() == 2
+        workspace1 = (M, K)
-        num_dp = self.num_dispatchers
+        workspace2 = (0, 0)
-        num_experts = local_num_experts
+        output = (M, K)
-        max_num_tokens = self.max_num_tokens
+        return (workspace1, workspace2, output, a.dtype)
-        workspace2 = (0, 0, 0)
-        output = (num_experts, max_num_tokens * num_dp, N)
-        return (output, workspace2, output, a.dtype)
 
     def apply(
         self,
@@ -185,17 +279,29 @@ class BatchedOAITritonExperts(mk.FusedMoEPermuteExpertsUnpermute):
         expert_tokens_meta: Optional[mk.ExpertTokensMetadata],
         apply_router_weight_on_input: bool,
     ):
-        return triton_kernel_fused_experts(
+        if expert_map is not None:
-            output,
+            topk_ids = expert_map[topk_ids]
+
+        local_num_experts = w1.size(0)
+        if global_num_experts == -1:
+            global_num_experts = local_num_experts
+
+        routing_data, gather_indx, scatter_indx = self._make_routing_data(
+            topk_ids, topk_weights, local_num_experts)
+
+        experts_output = triton_kernel_fused_experts(
+            None,
             hidden_states,
             w1,
             w2,
-            routing_data=None,
+            routing_data,
-            gather_indx=None,
+            gather_indx,
-            scatter_indx=None,
+            scatter_indx,
             activation=activation,
             quant_config=self.quant_config,
             apply_router_weight_on_input=False,
-            global_num_experts=global_num_experts,
+            global_num_experts=local_num_experts,
-            expert_map=expert_map,
+            expert_map=None,  # applied already
             a1q_scale=a1q_scale)
+
+        output.copy_(experts_output, non_blocking=True)

vllm/model_executor/layers/fused_moe/layer.py

@@ -800,6 +800,49 @@ def get_compressed_expert_map(expert_map: torch.Tensor) -> str:
         for local_index, global_index in zip(local_indices, global_indices))
 
 
+def maybe_roundup_hidden_size(
+        hidden_size: int, act_dtype: torch.dtype,
+        quant_config: Optional[QuantizationConfig],
+        moe_parallel_config: FusedMoEParallelConfig) -> int:
+    """
+    Given layer hidden size and MoE configurations, round up hidden_size
+    if necessary.
+    
+    Args:
+        hidden_size(int): Layer hidden-size
+        act_dtype: Data type of the layer activations.
+        quant_config(FusedMoEQuantConfig): Fused MoE quantization configuration.
+        moe_parallel_config(FusedMoEParallelConfig): Fused MoE parallelization
+            strategy configuration.
+    
+    Return:
+        Rounded up hidden_size if rounding up is required based on the configs.
+        Original hidden size otherwise.
+    """
+
+    if (moe_parallel_config.use_deepep_ht_kernels):
+        hidden_size = (
+            DeepEPHTPrepareAndFinalize.maybe_roundup_layer_hidden_size(
+                hidden_size, act_dtype))
+
+    # we are padding globally so EP buffer allocation works
+    if quant_config and quant_config.get_name() == "mxfp4":
+
+        from vllm.model_executor.layers.quantization.mxfp4 import (
+            Mxfp4Backend, get_mxfp4_backend)
+        current_mxfp4_backend = get_mxfp4_backend()
+        if (current_mxfp4_backend == Mxfp4Backend.SM90_FI_MXFP4_BF16
+                or current_mxfp4_backend
+                == Mxfp4Backend.SM100_FI_MXFP4_MXFP8_CUTLASS):
+            hidden_size = round_up(hidden_size, 128)
+        elif (current_platform.is_rocm() or current_mxfp4_backend
+              == Mxfp4Backend.SM100_FI_MXFP4_MXFP8_TRTLLM
+              or current_mxfp4_backend == Mxfp4Backend.SM100_FI_MXFP4_BF16):
+            hidden_size = round_up(hidden_size, 256)
+
+    return hidden_size
+
+
 @CustomOp.register("fused_moe")
 class FusedMoE(CustomOp):
     """FusedMoE layer for MoE models.
@@ -856,6 +899,18 @@ class FusedMoE(CustomOp):
             params_dtype = torch.get_default_dtype()
         self.params_dtype = params_dtype
 
+        vllm_config = get_current_vllm_config()
+
+        # FIXME (varun): We should have a better way of inferring the activation
+        # datatype. This works for now as the tensor datatype entering the MoE
+        # operation is typically unquantized (i.e. float16/bfloat16).
+        if vllm_config.model_config is not None:
+            moe_in_dtype = vllm_config.model_config.dtype
+        else:
+            # TODO (bnell): This is a hack to get test_mixtral_moe to work
+            # since model_config is not set in the pytest test.
+            moe_in_dtype = params_dtype
+
         tp_size_ = (tp_size if tp_size is not None else
                     get_tensor_model_parallel_world_size())
         dp_size_ = (dp_size
@@ -865,7 +920,6 @@ class FusedMoE(CustomOp):
         if self.is_sequence_parallel:
             self.sp_size = tp_size_
 
-        vllm_config = get_current_vllm_config()
         self.moe_parallel_config: FusedMoEParallelConfig = (
             FusedMoEParallelConfig.make(
                 tp_size_=tp_size_,
@@ -874,19 +928,10 @@ class FusedMoE(CustomOp):
 
         self.global_num_experts = num_experts + num_redundant_experts
 
-        # we are padding globally so EP buffer allocation works
+        # Round up hidden size if needed.
-        if quant_config and quant_config.get_name() == "mxfp4":
+        hidden_size = maybe_roundup_hidden_size(hidden_size, moe_in_dtype,
-            from vllm.model_executor.layers.quantization.mxfp4 import (
+                                                quant_config,
-                Mxfp4Backend, get_mxfp4_backend)
+                                                self.moe_parallel_config)
-            current_mxfp4_backend = get_mxfp4_backend()
-            if (current_mxfp4_backend == Mxfp4Backend.SM90_FI_MXFP4_BF16
-                    or current_mxfp4_backend
-                    == Mxfp4Backend.SM100_FI_MXFP4_MXFP8_CUTLASS):
-                hidden_size = round_up(hidden_size, 128)
-            elif (current_platform.is_rocm() or current_mxfp4_backend
-                  == Mxfp4Backend.SM100_FI_MXFP4_MXFP8_TRTLLM or
-                  current_mxfp4_backend == Mxfp4Backend.SM100_FI_MXFP4_BF16):
-                hidden_size = round_up(hidden_size, 256)
 
         # For smuggling this layer into the fused moe custom op
         compilation_config = vllm_config.compilation_config
@@ -967,20 +1012,13 @@ class FusedMoE(CustomOp):
             raise ValueError("Only softmax scoring function is supported for "
                              "non-grouped topk.")
 
-        if vllm_config.model_config is not None:
-            model_dtype = vllm_config.model_config.dtype
-        else:
-            # TODO (bnell): This is a hack to get test_mixtral_moe to work
-            # since model_config is not set in the pytest test.
-            model_dtype = params_dtype
-
         moe = FusedMoEConfig(
             num_experts=self.global_num_experts,
             experts_per_token=top_k,
             hidden_dim=hidden_size,
             num_local_experts=self.local_num_experts,
             moe_parallel_config=self.moe_parallel_config,
-            in_dtype=model_dtype,
+            in_dtype=moe_in_dtype,
             max_num_tokens=envs.VLLM_MOE_DP_CHUNK_SIZE,
             has_bias=has_bias,
         )

vllm/model_executor/layers/fused_moe/modular_kernel.py

@@ -76,7 +76,7 @@ def _moe_problem_size(
     """
     assert w1.dim() == 3 and w2.dim() == 3
     E, N, _ = w1.size()
-    K = w2.size(1)
+    K = a1.size(-1)
 
     if a1.dim() == 2:
         # Make sure we are using the correct a1 (pre-permute).

vllm/model_executor/layers/quantization/mxfp4.py

@@ -13,7 +13,10 @@ from vllm.model_executor.layers.fused_moe import (FusedMoE, FusedMoEConfig,
                                                   FusedMoEMethodBase)
 from vllm.model_executor.layers.fused_moe import modular_kernel as mk
 from vllm.model_executor.layers.fused_moe.config import (
-    FusedMoEQuantConfig, mxfp4_w4a4_moe_quant_config)
+    FusedMoEQuantConfig, mxfp4_w4a4_moe_quant_config,
+    mxfp4_w4a16_moe_quant_config)
+from vllm.model_executor.layers.fused_moe.gpt_oss_triton_kernels_moe import (
+    OAITritonExperts)
 from vllm.model_executor.layers.fused_moe.trtllm_moe import TrtLlmGenExperts
 from vllm.model_executor.layers.linear import (LinearBase,
                                                UnquantizedLinearMethod)
@@ -578,9 +581,14 @@ class Mxfp4MoEMethod(FusedMoEMethodBase):
             layer.w13_bias = Parameter(w13_bias, requires_grad=False)
             layer.w2_bias = Parameter(w2_bias, requires_grad=False)
 
-            # FIXME warp need to be adjusted based on batch size
+            # Ideally we'd use FusedMoEModularKernel.prepare_finalize object
-            # only apply to  batched mode
+            # (stored in self.fused_experts) to determine if the MoE has a
-            if self.moe.use_ep:
+            # batched activation format. As self.fused_experts is not
+            # initialized at this point, we resort to checking the MoE config
+            # directly.
+            is_batched_moe = (self.moe.use_pplx_kernels
+                              or self.moe.use_deepep_ll_kernels)
+            if is_batched_moe:
                 num_warps = 4 if envs.VLLM_MOE_DP_CHUNK_SIZE <= 512 else 8
             else:
                 num_warps = 8
@@ -640,10 +648,15 @@ class Mxfp4MoEMethod(FusedMoEMethodBase):
         if self.mxfp4_backend == Mxfp4Backend.TRITON:
             w1_scale = self.w13_precision_config
             w2_scale = self.w2_precision_config
+            return mxfp4_w4a16_moe_quant_config(
+                w1_bias=layer.w13_bias,
+                w2_bias=layer.w2_bias,
+                w1_scale=w1_scale,
+                w2_scale=w2_scale,
+            )
         else:
             w1_scale = layer.w13_weight_scale
             w2_scale = layer.w2_weight_scale
-
             return mxfp4_w4a4_moe_quant_config(
                 w1_bias=layer.w13_bias,
                 w2_bias=layer.w2_bias,
@@ -661,6 +674,7 @@ class Mxfp4MoEMethod(FusedMoEMethodBase):
             raise NotImplementedError(
                 "Mxfp4 does not support batched experts format for EP")
         else:
+            assert self.moe_quant_config is not None
             if (self.mxfp4_backend == Mxfp4Backend.SM100_FI_MXFP4_MXFP8_TRTLLM
                     or self.mxfp4_backend == Mxfp4Backend.SM100_FI_MXFP4_BF16):
                 # B200 code-path
@@ -671,13 +685,10 @@ class Mxfp4MoEMethod(FusedMoEMethodBase):
                     # TODO(bnell): part of quant_config
                     "max_capture_size": self.max_capture_size,
                 }
-                assert self.moe_quant_config is not None
                 return TrtLlmGenExperts(self.moe, self.moe_quant_config,
                                         **kwargs)
             else:
-                # Use matmul_ogs from triton_kernels here!
+                return OAITritonExperts(self.moe_quant_config)
-                raise NotImplementedError(
-                    "Mxfp4 does not support non-batched experts format for EP")
 
     def _route_and_experts(
             self,
@@ -722,10 +733,16 @@ class Mxfp4MoEMethod(FusedMoEMethodBase):
             logical_to_physical_map=logical_to_physical_map,
             logical_replica_count=logical_replica_count)
 
+        w13_weight = (self.w13_weight_triton_tensor
+                      if layer.w13_weight is None else layer.w13_weight)
+        w2_weight = (self.w2_weight_triton_tensor
+                     if layer.w2_weight is None else layer.w2_weight)
+        assert all([w is not None for w in [w13_weight, w2_weight]])
+
         return self.fused_experts(
             hidden_states=x,
-            w1=layer.w13_weight,
+            w1=w13_weight,
-            w2=layer.w2_weight,
+            w2=w2_weight,
             topk_weights=topk_weights,
             topk_ids=topk_ids,
             inplace=True,