✨ [llm][npu][quant] Add W8A8 MXFP8 quantization for Qwen3 MoE on Ascend NPU (#30768)

Co-authored-by: Артем Савкин <58187114+OrangeRedeng@users.noreply.github.com>
Co-authored-by: ronnie_zheng <zl19940307@163.com>

python/sglang/srt/arg_groups/overrides.py

@@ -2031,7 +2031,13 @@ def _moe_runner_backend_quant_constraints(view: Any) -> dict:
                 "--moe-runner-backend flashinfer_trtllm or "
                 "flashinfer_trtllm_routed."
             )
-    if view.quantization == "mxfp8":
+    # Ascend runs MXFP8 MoE on the Ascend runner; every backend selected below is
+    # CUDA/ROCm-only. Forcing one here would not merely pick the wrong runner:
+    # FusedMoE keys its w1/w3 shard swap ("flashinfer assumes w31") and its
+    # 128-alignment round-up off flashinfer_trtllm, so the experts would silently
+    # load with gate and up exchanged. Leave the backend at "auto" and let
+    # create_moe_runner resolve it to ASCEND.
+    if view.quantization == "mxfp8" and not is_npu():
         from sglang.srt.server_args import MXFP8_MOE_RUNNER_BACKEND_CHOICES
 
         is_gfx95_mxfp8 = is_hip() and is_gfx95_supported()

python/sglang/srt/hardware_backend/npu/moe/init_routing.py

@@ -11,6 +11,24 @@ from typing import Optional, Tuple
 
 import torch
 
+# ``npu_moe_init_routing_v2`` quant_mode selecting MXFP8: the op emits an
+# float8_e4m3fn payload plus an e8m0 block scale, fusing the activation quant
+# that would otherwise need a separate ``npu_dynamic_mx_quant`` pass.
+MXFP8_QUANT_MODE = 3
+
+
+def _normalize_mxfp_scale(scale: torch.Tensor) -> torch.Tensor:
+    """Reshape a flat 2D e8m0 block scale ``[N, M]`` into pair-split ``[N, M//2, 2]``.
+
+    ``npu_moe_init_routing_v2(quant_mode=3)`` emits the scale flat, while the
+    grouped matmul wants the pair-split view. Already-3D scales (what
+    ``npu_dynamic_mx_quant`` returns) pass through untouched. Mirrors
+    vllm-ascend's ``maybe_normalize_mxfp_scale_layout``.
+    """
+    if scale is None or scale.ndim != 2:
+        return scale
+    return scale.reshape(scale.shape[0], scale.shape[1] // 2, 2)
+
 
 class BaseInitRouting(ABC):
     """Abstract base for NPU MoE init routing."""
@@ -95,6 +113,8 @@ class NPUMoEInitRouting_v2(BaseInitRouting):
         )
         if self.quant_mode == -1:
             pertoken_scale = None
+        elif self.quant_mode == MXFP8_QUANT_MODE:
+            pertoken_scale = _normalize_mxfp_scale(pertoken_scale)
         expert_tokens = expert_tokens.to(torch.int64)
         return hidden_states, expanded_row_idx, expert_tokens, pertoken_scale
 

python/sglang/srt/hardware_backend/npu/moe/matmul.py

@@ -1,4 +1,5 @@
 from abc import ABC, abstractmethod
+from typing import Tuple
 
 import torch
 
@@ -47,3 +48,42 @@ class GroupedMatmul(BaseMatmul):
             group_list=expert_tokens,
             output_dtype=output_dtype,
         )[0]
+
+
+class GroupedMatmulSwigluQuant(BaseMatmul):
+    """Grouped matmul with swiglu and requantisation fused into one kernel.
+
+    Used for the gate/up projection (gmm1) of block-scaled MoE: the kernel emits
+    activations already quantised for the following down projection, so the
+    caller has no separate activation step. Unlike ``GroupedMatmul`` it returns
+    ``(quantized_activations, block_scale)`` instead of a single tensor, and it
+    takes no ``output_dtype`` — the output dtype is set through ``quant_dtype``
+    in ``scale_args``.
+    """
+
+    def forward(
+        self,
+        layer: torch.nn.Module,
+        weight_prefix: str,
+        hidden_states: torch.Tensor,
+        expert_tokens: torch.Tensor,
+        output_dtype: torch.dtype = None,
+        group_list_type: int = 1,
+        transposed: bool = True,
+        **scale_args,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        weight = getattr(layer, f"{weight_prefix}_weight", None)
+        if weight is None:
+            raise AttributeError(
+                f"Weight attribute '{weight_prefix}_weight' not found in layer"
+            )
+        # This op wants a cumulative group_list while the plain grouped matmul
+        # keeps the COUNT form the dispatcher produces (group_list_type=1). The
+        # asymmetry is intentional.
+        group_list = expert_tokens.cumsum(0) if group_list_type == 1 else expert_tokens
+        return torch.ops.npu.npu_grouped_matmul_swiglu_quant_v2(
+            x=hidden_states,
+            weight=[weight] if transposed else [weight.transpose(1, 2)],
+            group_list=group_list,
+            **scale_args,
+        )

python/sglang/srt/hardware_backend/npu/moe/quant.py

@@ -1,5 +1,5 @@
 """
-Hidden state quantization utilities for NPU MoE.
+Quantization kernel wrappers for NPU MoE.
 
 Each class quantises hidden states and returns a (quantized_tensor, scale) tuple.
 For static quantization the scale is ``None``.
@@ -27,15 +27,26 @@ class HiddenStatesDynamicQuant(BaseHiddenStatesQuant):
     """
     Dynamic per‑token quantisation of hidden states.
 
+    ``torch.float8_e4m3fn`` selects the MX (block-scaled) op, whose scale is a
+    ``float8_e8m0fnu`` block scale ``[N, K//64, 2]`` rather than one scalar per
+    token; the int8/int4 dtypes keep the plain per-token op.
+
     Returns ``(quantized_hidden_states, per‑token_scale)``.
     """
 
+    def __init__(self, quant_dtype: torch.dtype) -> None:
+        super().__init__(quant_dtype)
+        if quant_dtype == torch.float8_e4m3fn:
+            self._op = torch.ops.npu.npu_dynamic_mx_quant
+        elif quant_dtype in (torch.int8, torch.quint4x2):
+            self._op = torch.ops.npu.npu_dynamic_quant
+        else:
+            raise ValueError(f"Unsupported dynamic quant dtype: {quant_dtype}")
+
     def __call__(
         self, hidden_states: torch.Tensor
     ) -> Tuple[torch.Tensor, torch.Tensor]:
-        quantized, scale = torch.ops.npu.npu_dynamic_quant(
-            hidden_states, dst_type=self.quant_dtype
-        )
+        quantized, scale = self._op(hidden_states, dst_type=self.quant_dtype)
         return quantized, scale
 
 

python/sglang/srt/hardware_backend/npu/quantization/moe_methods.py

@@ -1,7 +1,8 @@
-from typing import TYPE_CHECKING, Any, Dict, Optional
+from typing import TYPE_CHECKING, Any, Dict, Optional, Tuple
 
 import numpy as np
 import torch
+from torch.nn.parameter import Parameter
 
 from sglang.srt.environ import envs
 from sglang.srt.hardware_backend.npu.utils import npu_format_cast
@@ -13,14 +14,56 @@ if TYPE_CHECKING:
 
 import logging
 
-from sglang.srt.hardware_backend.npu.moe.hidden_states_quant import (
-    HiddenStatesDynamicQuant,
+from sglang.srt.hardware_backend.npu.moe.matmul import (
+    GroupedMatmul,
+    GroupedMatmulSwigluQuant,
+)
+from sglang.srt.hardware_backend.npu.moe.quant import HiddenStatesDynamicQuant
+from sglang.srt.hardware_backend.npu.quantization.linear_method_npu import (
+    _get_float8_e8m0fnu_dtype,
 )
-from sglang.srt.hardware_backend.npu.moe.matmul import GroupedMatmul
 
 logger = logging.getLogger(__name__)
 
 
+_E8M0_DTYPE = None
+
+
+def _require_e8m0_dtype():
+    """Resolve the e8m0 block-scale dtype, failing loudly if it is unavailable.
+
+    The grouped matmuls validate their scale-dtype arguments against torch_npu's
+    own dtype enum (``torch_npu.float8_e8m0fnu``, 293 on A5) and reject the torch
+    dtype object with "weight_scale_dtype only supports float8_e8m0fnu or None,
+    but the actual value is Float8_e8m0fnu" — hence torch_npu first, torch only
+    as a fallback. Dense ``npu_quant_matmul`` accepts either, which is why
+    ``_get_float8_e8m0fnu_dtype`` reads it off torch.
+
+    The MXFP8 ops take the scale dtype explicitly; passing None silently changes
+    how they interpret the scales, so a missing dtype must raise rather than
+    propagate.
+
+    torch_npu is imported lazily (and cached) so this module stays importable on
+    CUDA/CPU/AMD/XPU CI.
+    """
+    global _E8M0_DTYPE
+    if _E8M0_DTYPE is None:
+        from sglang.srt.utils import is_npu
+
+        if is_npu():
+            import torch_npu
+
+            _E8M0_DTYPE = getattr(torch_npu, "float8_e8m0fnu", None)
+        if _E8M0_DTYPE is None:
+            _E8M0_DTYPE = _get_float8_e8m0fnu_dtype()
+        if _E8M0_DTYPE is None:
+            raise RuntimeError(
+                "float8_e8m0fnu dtype not found — MXFP8 MoE requires Ascend A5 "
+                "with a torch_npu build exposing float8_e8m0fnu (torch_npu >= 2.9)."
+            )
+    return _E8M0_DTYPE
+
+
 # DEPRECATED METHOD
 # TODO: Remove in future realeses
 def fused_moe_npu(
@@ -714,3 +757,196 @@ class NPUUnquantMoEMethod(_NPUMoEMethodBase):
             transposed=False,
             **self._get_bias_args(quant_info, weight_prefix),
         )
+
+
+# ---------------------------------------------------------------------------
+#  NPUMXFP8MoEMethod
+# ---------------------------------------------------------------------------
+class NPUMXFP8MoEMethod(_NPUMoEMethodBase):
+    """MXFP8 MoE on Ascend A5 – float8_e4m3fn weights with e8m0 block scales.
+
+    Serves both the online config path (``--quantization mxfp8``, weights
+    quantised at load time) and the offline ModelSlim ``W8A8_MXFP8`` scheme
+    (weights already quantised); ``process_weights_after_loading`` tells the two
+    apart by weight dtype.
+
+    gmm1 re-quantises its own output, so it is a single fused kernel rather than
+    a matmul plus a separate activation: the runner calls
+    ``apply_fused_gmm1_swiglu`` for w13 and ``apply`` only for w2 — hence the
+    per-prefix matmul chosen here.
+
+    Where the *activation* quant happens depends on the dispatcher. On
+    ``ascend_tp`` it comes for free from ``npu_moe_init_routing_v2(quant_mode=3)``,
+    which emits the e4m3 payload and e8m0 scale as part of routing. DeepEP has no
+    mxfp8 dispatch dtype, so it hands over bf16 and w13 quantises the hidden
+    states itself before gmm1.
+    """
+
+    def __init__(self, weight_prefix: str):
+        super().__init__(quant_config=None)
+        if weight_prefix == "w13":
+            self.matmul = GroupedMatmulSwigluQuant()
+            self.hidden_states_quantizer = HiddenStatesDynamicQuant(
+                quant_dtype=torch.float8_e4m3fn
+            )
+        else:
+            self.matmul = GroupedMatmul()
+            self.hidden_states_quantizer = None
+
+    @staticmethod
+    def _quantize_weight_online(
+        weight: torch.Tensor, weight_prefix: str
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        """Quantise BF16/FP16 expert weights ``[E, N, K]`` to MXFP8 at load time.
+
+        Returns the e4m3 payload ``[E, N, K]`` and its e8m0 block scale
+        ``[E, N, K//64, 2]`` (block_size=32, already pair-split by the op).
+        """
+        if weight.dtype not in (torch.float16, torch.bfloat16):
+            logger.warning(
+                "NPUMXFP8MoEMethod: %s_weight dtype %s is not float16/bfloat16; "
+                "casting to bfloat16 before MXFP8 quantisation.",
+                weight_prefix,
+                weight.dtype,
+            )
+            weight = weight.to(torch.bfloat16)
+        # cpu offload may have moved the weight back to host memory.
+        if not weight.is_npu:
+            weight = weight.to(f"npu:{torch.npu.current_device()}")
+        return torch.ops.npu.npu_dynamic_mx_quant(weight, dst_type=torch.float8_e4m3fn)
+
+    def process_weights_after_loading(
+        self, layer: torch.nn.Module, weight_prefix: str
+    ) -> None:
+        self._validate_weight_prefix(layer, weight_prefix)
+
+        weight: torch.Tensor = getattr(layer, f"{weight_prefix}_weight").data
+        if weight.dtype == torch.float8_e4m3fn:
+            # Offline (ModelSlim) path: the checkpoint already holds e4m3 weights
+            # and {prefix}_weight_scale holds uint8 block scales [E, N, K//32].
+            # Only re-layout: split the flat scale axis into pairs to match what
+            # npu_dynamic_mx_quant produces online.
+            scale: torch.Tensor = getattr(layer, f"{weight_prefix}_weight_scale").data
+            scale = scale.reshape(scale.shape[0], -1, scale.shape[-1] // 2, 2)
+        else:
+            weight, scale = self._quantize_weight_online(weight, weight_prefix)
+
+        # FRACTAL_NZ before the transpose, never after. gmm1 asserts that weight
+        # and weight_scale carry the SAME transpose flag (CheckMXTranspose: "the
+        # transposition of weightScale/weight should be equal"), and the cast
+        # yields a physically retiled — hence non-transposed — tensor. Casting
+        # the [E, K, N] view would therefore leave the weight at false against a
+        # true scale and fail outright, which is why this cannot copy the int8
+        # MoE methods above (they transpose first, but carry no MX scale to keep
+        # in sync). Same order as the dense W4A8 path in linear_method_npu.py.
+        #
+        # A5 measurement, Qwen3-30B-A3B shapes, 128 experts (see
+        # llm/probe_mxfp8_moe_nz.py): +1.4% decode, +3.8% prefill against a 0.2-
+        # 0.3% noise floor, bit-identical outputs. Set
+        # SGLANG_NPU_DISABLE_ACL_FORMAT_WEIGHT to fall back to plain ND.
+        weight = npu_format_cast(weight)
+
+        # Both paths hand the grouped matmul weight [E, K, N] and scale
+        # [E, K//64, N, 2] as strided transpose views — DO NOT call
+        # .contiguous(). Beyond breaking the transpose-flag match above, it
+        # measures slower on the same probe: making both sides contiguous costs
+        # 6.2% on decode. This matches NPUMXFP8LinearMethod, msmodelslim's
+        # offline layout and vllm-ascend's AscendW8A8MXFP8DynamicFusedMoEMethod.
+        setattr(
+            layer,
+            f"{weight_prefix}_weight",
+            Parameter(weight.transpose(1, 2), requires_grad=False),
+        )
+        setattr(
+            layer,
+            f"{weight_prefix}_weight_scale",
+            Parameter(scale.transpose(1, 2), requires_grad=False),
+        )
+
+        if weight_prefix == "w13":
+            from sglang.srt.layers.moe import get_moe_a2a_backend
+
+            # DeepEP has no mxfp8 entry in its dispatch dtype table, so let it
+            # keep sending bf16; apply_fused_gmm1_swiglu quantises instead.
+            dispatcher_dtype = "bf16" if get_moe_a2a_backend().is_deepep() else "mxfp8"
+            self._set_dispatcher_output_dtype(layer, dispatcher_dtype)
+
+    def apply_fused_gmm1_swiglu(
+        self,
+        quant_info: "AscendQuantInfo",
+        hidden_states: torch.Tensor,
+        expert_tokens: torch.Tensor,
+        pertoken_scale: Optional[torch.Tensor],
+        group_list_type,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        """Gate/up projection, swiglu and requantisation in one kernel (gmm1).
+
+        Returns the e4m3 activations and their e8m0 block scale, i.e. exactly
+        what the w2 gmm needs, which is why the runner skips its activation step
+        for MXFP8.
+
+        ``pertoken_scale`` is None when the dispatcher handed over unquantised
+        hidden states (the DeepEP path), in which case the activation quant that
+        ascend_tp fuses into routing is done here instead. Both dispatchers
+        therefore reach the kernel below with the same e4m3 + e8m0 input.
+        """
+        if pertoken_scale is None:
+            hidden_states, pertoken_scale = self.hidden_states_quantizer(hidden_states)
+
+        e8m0_dtype = _require_e8m0_dtype()
+        return self.matmul.forward(
+            quant_info,
+            "w13",
+            hidden_states,
+            expert_tokens,
+            group_list_type=group_list_type,
+            transposed=True,
+            weight_scale=[quant_info.w13_weight_scale],
+            x_scale=pertoken_scale,
+            dequant_mode=2,
+            quant_mode=2,
+            dequant_dtype=torch.float32,
+            quant_dtype=torch.float8_e4m3fn,
+            # e4m3 is implicit for these two — it is not in the op's QUANT_DTYPES.
+            x_dtype=None,
+            weight_dtype=None,
+            weight_scale_dtype=e8m0_dtype,
+            x_scale_dtype=e8m0_dtype,
+        )
+
+    def apply(
+        self,
+        quant_info: "AscendQuantInfo",
+        hidden_states: torch.Tensor,
+        expert_tokens: torch.Tensor,
+        pertoken_scale: torch.Tensor,
+        output_dtype: torch.dtype,
+        weight_prefix: str,
+        group_list_type,
+    ) -> torch.Tensor:
+        if weight_prefix != "w2":
+            raise ValueError(
+                f"NPUMXFP8MoEMethod.apply only serves the w2 gmm, got "
+                f"'{weight_prefix}'. gmm1 fuses swiglu into a single op and must "
+                f"go through apply_fused_gmm1_swiglu, which returns a scale too."
+            )
+
+        e8m0_dtype = _require_e8m0_dtype()
+        scale_args: Dict[str, Any] = {
+            "scale": [getattr(quant_info, f"{weight_prefix}_weight_scale", None)],
+            "per_token_scale": [pertoken_scale],
+            "scale_dtype": e8m0_dtype,
+            "per_token_scale_dtype": e8m0_dtype,
+            "x_dtype": None,
+            "weight_dtype": None,
+        }
+        return self.matmul.forward(
+            quant_info,
+            weight_prefix,
+            hidden_states,
+            expert_tokens,
+            output_dtype,
+            group_list_type=group_list_type,
+            transposed=True,
+            **scale_args,
+        )

python/sglang/srt/hardware_backend/npu/quantization/online_moe_methods.py

@@ -0,0 +1,65 @@
+"""Online (config-driven) quantized FusedMoE methods for Ascend NPU.
+
+These are the ``--quantization <scheme>`` entry points: the checkpoint holds
+BF16/FP16 expert weights and the per-gmm kernels quantize them at load time.
+Offline (msmodelslim) checkpoints go through the ModelSlim schemes instead and
+reuse the same kernels.
+
+Kept out of ``moe_methods.py`` because ``unquant.py`` imports that module at
+module scope, so subclassing ``UnquantizedFusedMoEMethod`` there would be a
+circular import.
+"""
+
+from typing import TYPE_CHECKING, Optional
+
+import torch
+
+from sglang.srt.hardware_backend.npu.quantization.moe_methods import NPUMXFP8MoEMethod
+from sglang.srt.layers.moe.moe_runner import MoeRunner
+from sglang.srt.layers.moe.utils import MoeRunnerBackend, get_moe_runner_backend
+from sglang.srt.layers.quantization.unquant import UnquantizedFusedMoEMethod
+
+if TYPE_CHECKING:
+    from sglang.srt.layers.moe.moe_runner.base import MoeRunnerConfig
+    from sglang.srt.layers.quantization.base_config import QuantizationConfig
+
+
+class NPUMXFP8OnlineMoEMethod(UnquantizedFusedMoEMethod):
+    """Online MXFP8 FusedMoE entry point (``--quantization mxfp8`` on A5).
+
+    Weight creation, weight post-processing and the forward pass are identical
+    to the unquantized Ascend path — the only difference is which per-gmm kernel
+    the layer gets, so everything but ``create_moe_runner`` is inherited.
+    ``NPUMXFP8MoEMethod`` then quantizes the BF16 expert weights to MXFP8 in
+    ``process_weights_after_loading``.
+    """
+
+    def __init__(self, quant_config: Optional["QuantizationConfig"] = None):
+        super().__init__()
+        self.quant_config = quant_config
+
+    def create_moe_runner(
+        self, layer: torch.nn.Module, moe_runner_config: "MoeRunnerConfig"
+    ):
+        backend = get_moe_runner_backend()
+        if not (backend.is_auto() or backend.is_ascend()):
+            # Not merely a wrong-runner check. Because this method subclasses
+            # UnquantizedFusedMoEMethod it matches FusedMoE's shard-swap list, so
+            # a flashinfer backend would make the weight loader exchange the
+            # w1/w3 shards ("flashinfer assumes w31 format"). Every expert would
+            # then load with gate and up swapped, and gmm1's fused swiglu would
+            # compute silu(up) * gate — no error, just degenerate output.
+            raise ValueError(
+                "MXFP8 MoE on Ascend requires --moe-runner-backend 'auto' or "
+                f"'ascend', got {backend.value!r}."
+            )
+
+        # The kernels must be attached before the runner is built:
+        # AscendRunnerCore.__init__ reads layer.w2_kernel to pick its activation.
+        layer.w13_kernel = NPUMXFP8MoEMethod("w13")
+        layer.w2_kernel = NPUMXFP8MoEMethod("w2")
+        moe_runner_config.layer = layer
+        self.moe_runner_config = moe_runner_config
+        self.runner = MoeRunner(MoeRunnerBackend.ASCEND, moe_runner_config)
+        # Inherited apply() consults this; aiter is CUDA/ROCm-only.
+        self._aiter_runner = None

python/sglang/srt/hardware_backend/npu/utils.py

@@ -113,18 +113,25 @@ def init_npu_backend():
 def _is_nz_aligned(tensor: torch.Tensor) -> bool:
     """Check whether the last two dims satisfy FRACTAL_NZ alignment rules.
 
-    Ascend FRACTAL_NZ requires:
-      BF16 / FP16 : both dims divisible by 16
-      INT8         : k % 16 == 0  and  n % 32 == 0
+    A fractal tile is 16 rows by 32 bytes (the C0_32 in the op's error strings),
+    so the row rule is always k % 16 and the column rule is 32 // itemsize:
+
+      BF16 / FP16  : k % 16 == 0  and  n % 16 == 0
+      INT8 / FP8   : k % 16 == 0  and  n % 32 == 0
       INT4         : k % 16 == 0  and  n % 64 == 0
-      FP4          : both dims divisible by 64
+
+    Unlisted dtypes fall through to True: this is a cheap pre-filter for known
+    bad combinations, not an authority — the op itself is.
     """
     if tensor.dim() < 2:
         return False
     k, n = tensor.shape[-2], tensor.shape[-1]
     if tensor.dtype in (torch.bfloat16, torch.float16):
         return k % 16 == 0 and n % 16 == 0
-    if tensor.dtype == torch.int8:
+    if tensor.dtype in (torch.int8, torch.float8_e4m3fn):
+        # e4m3 is single-byte like int8, so it shares the column rule. Reached
+        # only by the MXFP8 MoE weights; the packed-FP4 callers pass
+        # customize_dtype and return before this check.
         return k % 16 == 0 and n % 32 == 0
     if tensor.dtype in (torch.uint8, torch.int32):
         # INT4 is typically packed into uint8/int32; be conservative

python/sglang/srt/layers/moe/moe_runner/ascend.py

@@ -17,6 +17,7 @@ from sglang.srt.hardware_backend.npu.moe.activation import (
     NPUSwigluStepAndMul,
 )
 from sglang.srt.hardware_backend.npu.quantization.moe_methods import (
+    NPUMXFP8MoEMethod,
     NPUW4A8Int8MoEMethod,
     NPUW8A8Int8MoEMethod,
 )
@@ -87,7 +88,15 @@ class AscendRunnerCore(MoeRunnerCore):
 
         kernel = config.layer.w2_kernel
 
-        if get_moe_a2a_backend().is_deepep():
+        if isinstance(kernel, NPUMXFP8MoEMethod):
+            # MXFP8 fuses gate/up + swiglu + requant into gmm1, so there is no
+            # separate activation step — run() skips it. Left None on purpose so
+            # that reaching for it fails loudly instead of silently applying an
+            # unfused swiglu to already-requantised activations. This holds for
+            # both dispatchers: ascend_tp gets its activation quant fused into
+            # routing, DeepEP dispatches bf16 and gmm1 quantises it itself.
+            self.activation = None
+        elif get_moe_a2a_backend().is_deepep():
             # DeepEP path: use a unified kernel that decides quantisation
             is_quant_kernel = isinstance(
                 kernel, (NPUW4A8Int8MoEMethod, NPUW8A8Int8MoEMethod)
@@ -134,30 +143,44 @@ class AscendRunnerCore(MoeRunnerCore):
         expert_tokens = runner_input.expert_tokens
         group_list_type = runner_input.group_list_type
 
-        # --- w13 (gate & up) projection ---
-        hidden_states = self.config.layer.w13_kernel.apply(
-            quant_info,
-            x,
-            expert_tokens,
-            pertoken_scale=runner_input.hidden_states_scale,
-            output_dtype=original_dtype,
-            weight_prefix="w13",
-            group_list_type=group_list_type,
-        )
+        w13_kernel = self.config.layer.w13_kernel
 
-        # --- Activation ---
-        # The DeepEP kernel expects extra dispatch metadata
-        if isinstance(self.activation, NPUSwigluDeepEPKernel):
-            hidden_states, pertoken_scale = self.activation._apply_activation(
-                hidden_states,
-                group_list=expert_tokens,
+        if isinstance(w13_kernel, NPUMXFP8MoEMethod):
+            # --- w13 projection + activation, fused into one kernel ---
+            # MXFP8 gmm1 returns activations already requantised for gmm2, so
+            # there is no separate activation step to run.
+            hidden_states, pertoken_scale = w13_kernel.apply_fused_gmm1_swiglu(
+                quant_info,
+                x,
+                expert_tokens,
+                pertoken_scale=runner_input.hidden_states_scale,
                 group_list_type=group_list_type,
             )
         else:
-            hidden_states, pertoken_scale = self.activation._apply_activation(
-                hidden_states
+            # --- w13 (gate & up) projection ---
+            hidden_states = w13_kernel.apply(
+                quant_info,
+                x,
+                expert_tokens,
+                pertoken_scale=runner_input.hidden_states_scale,
+                output_dtype=original_dtype,
+                weight_prefix="w13",
+                group_list_type=group_list_type,
             )
 
+            # --- Activation ---
+            # The DeepEP kernel expects extra dispatch metadata
+            if isinstance(self.activation, NPUSwigluDeepEPKernel):
+                hidden_states, pertoken_scale = self.activation._apply_activation(
+                    hidden_states,
+                    group_list=expert_tokens,
+                    group_list_type=group_list_type,
+                )
+            else:
+                hidden_states, pertoken_scale = self.activation._apply_activation(
+                    hidden_states
+                )
+
         # --- w2 (down) projection ---
         hidden_states = self.config.layer.w2_kernel.apply(
             quant_info,

python/sglang/srt/layers/moe/token_dispatcher/ascend_tp.py

@@ -9,6 +9,7 @@ from sglang.srt.hardware_backend.npu.moe.finalize_routing import (
     NPUFinalizeRouting,
 )
 from sglang.srt.hardware_backend.npu.moe.init_routing import (
+    MXFP8_QUANT_MODE,
     NPUMoEInitRouting_v2,
 )
 from sglang.srt.layers.moe.moe_runner.base import MoeRunnerConfig
@@ -84,6 +85,10 @@ class AscendTPDispatcher(BaseDispatcher):
             self.init = NPUMoEInitRouting_v2(quant_mode=1)
             self.finalize = NPUFinalizeRouting(drop_pad_mode=2)
             self.group_list_type = 1
+        elif self.ascend_dispatcher_output_dtype == DispatcherOutputDtype.MXFP8:
+            self.init = NPUMoEInitRouting_v2(quant_mode=MXFP8_QUANT_MODE)
+            self.finalize = NPUFinalizeRouting(drop_pad_mode=2)
+            self.group_list_type = 1
         else:
             raise ValueError(
                 f"Unsupported ascend_dispatcher_output_dtype: {self.ascend_dispatcher_output_dtype}"

python/sglang/srt/layers/moe/utils.py

@@ -209,12 +209,14 @@ class DispatcherOutputDtype(Enum):
     - FP8: dispatch hidden states in fp8
     - INT8: dispatch hidden states in int8
     - NVFP4: dispatch hidden states in nvfp4
+    - MXFP8: dispatch hidden states in mxfp8 (fp8_e4m3 + e8m0 block scale)
     """
 
     BF16 = "bf16"
     FP8 = "fp8"
     INT8 = "int8"
     NVFP4 = "nvfp4"
+    MXFP8 = "mxfp8"
 
 
 def get_deepep_output_dtype(self) -> DispatcherOutputDtype:

python/sglang/srt/layers/quantization/fp8.py

@@ -360,6 +360,13 @@ class Fp8Config(QuantizationConfig):
                     layer.use_triton_kernels, layer.use_flashinfer_trtllm_moe
                 )
 
+            if is_npu() and self.use_mxfp8:
+                from sglang.srt.hardware_backend.npu.quantization.online_moe_methods import (
+                    NPUMXFP8OnlineMoEMethod,
+                )
+
+                return NPUMXFP8OnlineMoEMethod(self)
+
             fp8_method = Fp8MoEMethod(self)
 
             if self.is_fp4_experts and self.dequant_fp4_to_fp8:

python/sglang/srt/layers/quantization/modelslim/modelslim.py

@@ -18,6 +18,7 @@ from sglang.srt.layers.quantization.base_config import (
 from sglang.srt.layers.quantization.modelslim.schemes import (
     ModelSlimMXFP4Scheme,
     ModelSlimMXFP4W4A8Scheme,
+    ModelSlimMXFP8MoEScheme,
     ModelSlimMXFP8Scheme,
     ModelSlimW4A4Int4,
     ModelSlimW4A4Int4MoE,
@@ -238,6 +239,7 @@ class ModelSlimConfig(QuantizationConfig):
             ("W4A4_DYNAMIC", ModelSlimW4A4Int4MoE),
             ("W4A8_DYNAMIC", ModelSlimW4A8Int8MoE),
             ("W8A8_DYNAMIC", ModelSlimW8A8Int8MoE),
+            ("W8A8_MXFP8", ModelSlimMXFP8MoEScheme),
         ]
 
         # Try multiple naming conventions:

python/sglang/srt/layers/quantization/modelslim/schemes/__init__.py

@@ -10,6 +10,7 @@ from .modelslim_mxfp4_w4a8 import ModelSlimMXFP4W4A8Scheme
 from .modelslim_mxfp4 import ModelSlimMXFP4Scheme
 
 # isort: on
+from .modelslim_mxfp8_moe import ModelSlimMXFP8MoEScheme
 from .modelslim_w4a4_int4 import ModelSlimW4A4Int4
 from .modelslim_w4a4_int4_moe import ModelSlimW4A4Int4MoE
 from .modelslim_w4a8_int8_moe import ModelSlimW4A8Int8MoE
@@ -22,6 +23,7 @@ __all__ = [
     "ModelSlimMXFP8Scheme",
     "ModelSlimMXFP4W4A8Scheme",
     "ModelSlimMXFP4Scheme",
+    "ModelSlimMXFP8MoEScheme",
     "ModelSlimW8A8Int8",
     "ModelSlimW4A4Int4",
     "ModelSlimW4A4Int4MoE",

python/sglang/srt/layers/quantization/modelslim/schemes/modelslim_mxfp8_moe.py

@@ -0,0 +1,114 @@
+"""ModelSlim MXFP8 offline scheme for MoE layers on Ascend NPU (SRT).
+
+Loads weights pre-quantised by msmodelslim: float8_e4m3fn weights + uint8 block
+scales (block_size=32). The layout transform and the forward pass are delegated
+to ``NPUMXFP8MoEMethod`` -- the same kernel the online MXFP8 MoE path uses.
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import Any, Dict
+
+import torch
+
+from sglang.srt.hardware_backend.npu.quantization.moe_methods import NPUMXFP8MoEMethod
+from sglang.srt.layers.quantization.modelslim.schemes import ModelSlimMoEScheme
+from sglang.srt.utils import set_weight_attrs
+
+logger = logging.getLogger(__name__)
+
+__all__ = [
+    "ModelSlimMXFP8MoEScheme",
+]
+
+# Block (group) size of the msmodelslim MXFP8 export format.
+MXFP8_BLOCK_SIZE = 32
+
+
+class ModelSlimMXFP8MoEScheme(ModelSlimMoEScheme):
+    """
+    Offline MXFP8 MoE scheme that creates weights for either the
+    w13 (gate+up) or w2 (down) projection group.
+
+    Two instances of this class are used per MoE layer:
+      - weight_prefix="w13"   → handles the fused gate_proj + up_proj weights
+      - weight_prefix="w2"    → handles the down_proj weights
+
+    The float8_e4m3fn weight dtype allocated here is what tells
+    ``NPUMXFP8MoEMethod.process_weights_after_loading`` to take its offline
+    (re-layout only) branch instead of quantising the weights itself.
+    """
+
+    def __init__(
+        self,
+        quant_config: Dict[str, Any],
+        weight_prefix: str,  # "w13" or "w2"
+    ) -> None:
+        if weight_prefix not in ("w13", "w2"):
+            raise ValueError(
+                f"weight_prefix must be 'w13' or 'w2', got '{weight_prefix}'"
+            )
+        self.quant_config = quant_config
+        self.weight_prefix = weight_prefix
+        self.kernel = NPUMXFP8MoEMethod(weight_prefix)
+
+    def create_weights(
+        self,
+        layer: torch.nn.Module,
+        num_experts: int,
+        hidden_size: int,
+        intermediate_size_per_partition: int,
+        **extra_weight_attrs,
+    ) -> None:
+        from sglang.srt.layers.moe.fused_moe_triton import FusedMoeWeightScaleSupported
+
+        self.num_experts = num_experts
+        extra_weight_attrs.update(
+            {"quant_method": FusedMoeWeightScaleSupported.BLOCK.value}
+        )
+
+        # Determine shape based on weight group
+        if self.weight_prefix == "w13":
+            a_dim = 2 * intermediate_size_per_partition
+            b_dim = hidden_size
+        else:  # w2
+            a_dim = hidden_size
+            b_dim = intermediate_size_per_partition
+
+        prefix = self.weight_prefix
+
+        # Create and register weight: [E, N, K] float8_e4m3fn
+        weight_name = f"{prefix}_weight"
+        weight = torch.nn.Parameter(
+            torch.empty(num_experts, a_dim, b_dim, dtype=torch.float8_e4m3fn),
+            requires_grad=False,
+        )
+        layer.register_parameter(weight_name, weight)
+        set_weight_attrs(weight, extra_weight_attrs)
+
+        # Create and register block scale: [E, N, K // 32] uint8 (e8m0)
+        scale_name = f"{prefix}_weight_scale"
+        scale = torch.nn.Parameter(
+            torch.empty(
+                num_experts, a_dim, b_dim // MXFP8_BLOCK_SIZE, dtype=torch.uint8
+            ),
+            requires_grad=False,
+        )
+        layer.register_parameter(scale_name, scale)
+        set_weight_attrs(scale, extra_weight_attrs)
+
+        # MXFP8 is a pure scale format: the e8m0 block exponent above carries
+        # everything, there is no zero point. The int8/int4 schemes do have one,
+        # so ModelSlimMoEMethod.apply reads layer.{w13,w2}_weight_offset
+        # unconditionally when it builds AscendQuantInfo (where the field is
+        # Optional). Register it as None so the attribute exists and resolves to
+        # "no offset" rather than raising AttributeError. A None parameter is
+        # skipped by named_parameters(), so no weight loader looks for it.
+        layer.register_parameter(f"{prefix}_weight_offset", None)
+
+    def process_weights_after_loading(self, layer: torch.nn.Module) -> None:
+        """
+        Delegate weight processing to the NPU kernel for the fixed weight group.
+        """
+        self.kernel.process_weights_after_loading(layer, self.weight_prefix)

python/sglang/srt/layers/quantization/unquant.py

@@ -438,10 +438,12 @@ class UnquantizedFusedMoEMethod(FusedMoEMethodBase, MultiPlatformOp):
                 layer.num_local_experts, *new_shape_w2
             )
         if _is_npu:
+            # The kernels set the dispatcher output dtype themselves -- they are
+            # the ones that know what their gmms expect. NPUUnquantMoEMethod
+            # already sets bf16 here, and hardcoding it a second time would
+            # clobber a subclass that attached a quantized kernel instead.
             layer.w13_kernel.process_weights_after_loading(layer, "w13")
             layer.w2_kernel.process_weights_after_loading(layer, "w2")
-            if hasattr(layer, "dispatcher"):
-                layer.dispatcher.set_quant_config({"dispatcher_output_dtype": "bf16"})
 
         return
 

python/sglang/srt/models/qwen3_moe.py

@@ -271,11 +271,21 @@ class Qwen3MoeSparseMoeBlock(nn.Module):
             routing_method_type=RoutingMethodType.Renormalize,
         )
 
+        # Router gate: description-driven quant, mirroring vllm-ascend. Only the
+        # offline ModelSlim path (which carries a per-layer quant_model_description)
+        # may quantise the gate — if the checkpoint stored it as MXFP8 it is loaded
+        # and dequantised correctly instead of cast to bf16 without its block scale.
+        # The online Fp8/mxfp8 path keeps the gate in bf16 (unchanged, verified).
+        gate_quant_config = (
+            quant_config
+            if (quant_config is not None and quant_config.get_name() == "modelslim")
+            else None
+        )
         self.gate = ReplicatedLinear(
             config.hidden_size,
             config.num_experts,
             bias=False,
-            quant_config=None,
+            quant_config=gate_quant_config,
             prefix=add_prefix("gate", prefix),
         )