feat(moe): add Marlin W16A16 fused MoE behind VLLM_USE_MARLIN_W16A16_MOE

新增环境变量 VLLM_USE_MARLIN_W16A16_MOE，用于显式启用 Marlin W16A16 MoE experts
在 fused_moe 中当开关开启且实现可用时，调用 fused_experts_impl_w16a16_marlin
增加 Marlin W16A16 MoE 实现与 reduce 路径

vllm/envs.py

@@ -242,6 +242,8 @@ if TYPE_CHECKING:
     VLLM_USE_FUSE_SILU_AND_MUL: bool = False
     VLLM_USE_OPT_RESHAPE_AND_CACHE: bool = False
     VLLM_USE_TOPK_RENORM: bool = False
+    VLLM_USE_FUSED_RMS_ROPE: bool = False
+    VLLM_USE_MARLIN_W16A16_MOE:bool = False
 
 
 def get_default_cache_root():
@@ -1675,6 +1677,14 @@ environment_variables: dict[str, Callable[[], Any]] = {
         lambda:
         (os.environ.get("VLLM_USE_TOPK_RENORM", "True").lower() in
                 ("true", "1")),
+    # vLLM will use fused RMS + RoPE kernel
+    "VLLM_USE_FUSED_RMS_ROPE":
+        lambda: (os.environ.get("VLLM_USE_FUSED_RMS_ROPE", "False").lower() in
+                 ("true", "1")),
+    # vLLM will use Marlin W16A16 kernel for MoE experts
+    "VLLM_USE_MARLIN_W16A16_MOE":
+        lambda: (os.environ.get("VLLM_USE_MARLIN_W16A16_MOE", "False").lower() in
+                 ("true", "1")),
 }
 
 # --8<-- [end:env-vars-definition]

vllm/model_executor/layers/fused_moe/fuse_moe_w16a16_marlin.py

+import functools
+import json
+import os
+from typing import Any, Callable, Dict, List, Optional, Tuple
+import vllm.envs as envs
+from vllm import _custom_ops as ops
+from vllm.model_executor.layers.fused_moe.moe_align_block_size import (
+    moe_align_block_size)
+import torch
+import triton
+import triton.language as tl
+import lmslim.envs as lsenvs
+
+use_lightop = lsenvs.LMSLIM_USE_LIGHTOP
+device_name = lsenvs.LMSLIM_GPU_NAME
+num_cus= torch.cuda.get_device_properties(torch.cuda.current_device()).multi_processor_count
+from vllm.model_executor.layers.fused_moe.fused_moe import get_moe_cache
+if use_lightop:
+    from lightop import moe_gemm_marlin_w16a16, get_moe_cuda_marlin_config_w16a16
+    from lightop import op as op
+@torch.compile
+def moe_sum_reduce_torch_compile(x, out, routed_scaling_factor):
+    torch.sum(x, dim=1, out=out)
+    out.mul_(routed_scaling_factor)
+
+
+@triton.jit
+def _moe_sum_reduce_kernel(
+        input_ptr,
+        input_stride_0,
+        input_stride_1,
+        input_stride_2,
+        output_ptr,
+        output_stride_0,
+        output_stride_1,
+        token_num: int,
+        topk_num: int,
+        hidden_dim: int,
+        routed_scaling_factor: tl.constexpr,
+        BLOCK_M: tl.constexpr,
+        BLOCK_DIM: tl.constexpr,
+        NUM_STAGE: tl.constexpr,
+):
+    input_stride_0 = tl.cast(input_stride_0, dtype=tl.int64)
+    input_stride_1 = tl.cast(input_stride_1, dtype=tl.int64)
+    output_stride_0 = tl.cast(output_stride_0, dtype=tl.int64)
+
+    token_block_id = tl.program_id(0)
+    dim_block_id = tl.program_id(1)
+
+    token_start = token_block_id * BLOCK_M
+    token_end = min((token_block_id + 1) * BLOCK_M, token_num)
+
+    dim_start = dim_block_id * BLOCK_DIM
+    dim_end = min((dim_block_id + 1) * BLOCK_DIM, hidden_dim)
+
+    offs_dim = dim_start + tl.arange(0, BLOCK_DIM)
+
+    for token_index in range(token_start, token_end):
+        accumulator = tl.zeros((BLOCK_DIM,), dtype=tl.float32)
+        input_t_ptr = input_ptr + token_index * input_stride_0 + offs_dim
+        for i in tl.range(0, topk_num, num_stages=NUM_STAGE):
+            tmp = tl.load(
+                input_t_ptr + i * input_stride_1, mask=offs_dim < dim_end, other=0.0
+            )
+            accumulator += tmp
+        accumulator = accumulator * routed_scaling_factor
+        store_t_ptr = output_ptr + token_index * output_stride_0 + offs_dim
+        tl.store(
+            store_t_ptr,
+            accumulator.to(input_ptr.dtype.element_ty),
+            mask=offs_dim < dim_end,
+        )
+
+
+def moe_sum_reduce_triton(
+        input: torch.Tensor, output: torch.Tensor, routed_scaling_factor: float
+):
+    assert input.is_contiguous()
+    assert output.is_contiguous()
+
+    token_num, topk_num, hidden_dim = input.shape
+    assert output.shape[0] == token_num and output.shape[1] == hidden_dim
+
+    if token_num <= 32:
+        BLOCK_M = 1
+        BLOCK_DIM = 512
+        NUM_STAGE = 2
+        num_warps = 4
+
+    elif token_num <= 128:
+        BLOCK_M = 1
+        BLOCK_DIM = 1024
+        NUM_STAGE = 0
+        num_warps = 2
+
+    elif token_num <= 4096:
+        BLOCK_M = 1
+        BLOCK_DIM = 2048
+        NUM_STAGE = 0
+        num_warps = 2
+    else:
+        BLOCK_M = 1
+        BLOCK_DIM = 2048
+        NUM_STAGE = 2
+        num_warps = 8
+
+    grid = (
+        triton.cdiv(token_num, BLOCK_M),
+        triton.cdiv(hidden_dim, BLOCK_DIM),
+    )
+
+    _moe_sum_reduce_kernel[grid](
+        input,
+        *input.stride(),
+        output,
+        *output.stride(),
+        token_num=token_num,
+        topk_num=topk_num,
+        hidden_dim=hidden_dim,
+        routed_scaling_factor=routed_scaling_factor,
+        BLOCK_M=BLOCK_M,
+        BLOCK_DIM=BLOCK_DIM,
+        NUM_STAGE=NUM_STAGE,
+        num_warps=num_warps,
+    )
+    return
+
+def moe_reduce_dispatch(
+    intermediate_cache3: torch.Tensor,
+    out_hidden_states: torch.Tensor,
+    begin_chunk_idx: int,
+    end_chunk_idx: int,
+    routed_scaling_factor: float,
+    shared_output: Optional[torch.Tensor] = None,
+):
+    inter_cache_view = intermediate_cache3.view(*intermediate_cache3.shape)
+    n = intermediate_cache3.shape[0]
+
+    # 根据 n 大小选择不同的 reduce 实现
+    if 1 <= n <= 4:
+        moe_sum_reduce_torch_compile(inter_cache_view, out_hidden_states[begin_chunk_idx:end_chunk_idx], 1.0)
+    elif 4 < n <= 1024:
+        moe_sum_reduce_triton(inter_cache_view, out_hidden_states[begin_chunk_idx:end_chunk_idx], 1.0)
+    elif 1024 < n <= 32768:
+        ops.moe_sum_opt1(inter_cache_view, out_hidden_states[begin_chunk_idx:end_chunk_idx])
+    else:
+        ops.moe_sum(inter_cache_view, out_hidden_states[begin_chunk_idx:end_chunk_idx])
+        
+    # 根据 shared_output 是否存在决定怎么更新
+    if shared_output is not None:
+        out_hidden_states[begin_chunk_idx:end_chunk_idx].mul_(routed_scaling_factor).add_(shared_output[begin_chunk_idx:end_chunk_idx])
+    else:
+        out_hidden_states[begin_chunk_idx:end_chunk_idx].mul_(routed_scaling_factor)
+
+def round_up(x: int, y: int) -> int:
+    return ((x + y - 1) // y) * y
+
+def moe_align_block_size_lightop(
+    topk_ids: torch.Tensor,
+    block_size: int,
+    num_experts: int,
+    expert_map: Optional[torch.Tensor] = None,
+    expert_mask: Optional[torch.Tensor] = None,
+    num_local_tokens: Optional[torch.Tensor] = None,
+    pad_sorted_ids: bool = False,
+    ep_size: int = 8,
+    num_token: Optional[int] = None
+) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
+    
+    local_num_experts = num_experts // ep_size
+  
+    if num_token:
+        if num_token < block_size:
+            max_num_tokens_padded = min(topk_ids.numel() * block_size, topk_ids.numel() + local_num_experts * (block_size - 1))
+        else:
+            max_num_tokens_padded = topk_ids.numel() + local_num_experts * (block_size - 1)
+        sorted_ids = torch.full((max_num_tokens_padded,), fill_value=topk_ids.numel(), dtype=torch.int32, device=topk_ids.device)
+    else:
+        max_num_tokens_padded = topk_ids.numel() + local_num_experts * (block_size - 1)
+        if pad_sorted_ids:
+            max_num_tokens_padded = round_up(max_num_tokens_padded, block_size)
+        sorted_ids = torch.empty((max_num_tokens_padded, ),
+                                 dtype=torch.int32,
+                                 device=topk_ids.device)
+        sorted_ids.fill_(topk_ids.numel())
+    max_num_m_blocks = triton.cdiv(max_num_tokens_padded, block_size)
+    # Expert ids must be zeroed out to prevent index out of bounds error while
+    # mapping global expert ids to local expert ids in expert parallelism.
+    if expert_map is not None:
+        expert_ids = torch.zeros((max_num_m_blocks, ),
+                                dtype=torch.int32,
+                                device=topk_ids.device)
+    else:
+        expert_ids = torch.empty((max_num_m_blocks, ),
+                                dtype=torch.int32,
+                                device=topk_ids.device)
+    num_tokens_post_pad = torch.zeros((1),
+                                      dtype=torch.int32,
+                                      device=topk_ids.device)
+
+    op.moe_align_block_size(topk_ids, 
+                            num_experts, 
+                            block_size, 
+                            sorted_ids,
+                            expert_ids, 
+                            num_tokens_post_pad,
+                            expert_map,
+                            expert_mask,
+                            num_local_tokens,
+                            expert_map is not None)
+    return sorted_ids, expert_ids, num_tokens_post_pad
+
+
+
+def fused_experts_impl_w16a16_marlin(hidden_states: torch.Tensor,
+                                     w1: torch.Tensor,
+                                     w2: torch.Tensor,
+                                     w1_marlin: torch.Tensor,
+                                     w2_marlin: torch.Tensor,
+                                     topk_weights: torch.Tensor,
+                                     topk_ids: torch.Tensor,
+                                     cache13: torch.Tensor,
+                                     inplace: bool = False,
+                                     activation: str = "silu",
+                                     apply_router_weight_on_input: bool = False,
+                                     global_num_experts: int = -1,
+                                     expert_map: Optional[torch.Tensor] = None,
+                                     use_nn_moe: Optional[bool] = False,
+                                     routed_scaling_factor: Optional[float] = 1.0,
+                                     shared_output: Optional[torch.Tensor] = None,
+                                     num_local_tokens: Optional[torch.Tensor] = None,
+                                     expect_m: Optional[int] = -1,
+                                     ):
+
+    assert hidden_states.is_contiguous(), "Hidden_states must be contiguous"
+    assert w1.is_contiguous(), "Expert weights1 must be contiguous"
+    assert w2.is_contiguous(), "Expert weights2 must be contiguous"
+    # 当前只支持 bf16 fp16
+    assert hidden_states.dtype in [torch.bfloat16,torch.float16]
+    compute_type = hidden_states.dtype
+    assert use_lightop, (
+        "only BW and set LMSLIM_USE_LIGHTOP=1 support Marlin W16A16 MoE")
+
+    num_tokens, K = hidden_states.shape
+    E, twoN, K_w1 = w1.shape
+   
+    N = twoN // 2
+
+    E2, K_w2, N2_w2 = w2.shape
+   
+    if global_num_experts == -1:
+        global_num_experts = E
+
+    top_k_num = topk_ids.shape[1]
+    # We execute the fused_moe kernel in chunks to circumvent this issue:
+    # https://github.com/vllm-project/vllm/issues/5938
+    CHUNK_SIZE = envs.VLLM_FUSED_MOE_CHUNK_SIZE
+    M = min(num_tokens, CHUNK_SIZE)
+    # We can reuse the memory between these because by the time we need
+    # cache3, we're done with cache1
+
+    N2 = 2 * N
+    intermediate_cache1 = cache13[:M * top_k_num * N2].view(-1, N2)
+    intermediate_cache3 = cache13[:M * top_k_num * K]
+
+    # This needs separate memory since it's used concurrently with cache1
+    intermediate_cache2 = torch.empty((M * top_k_num, N),
+                                      device=hidden_states.device,
+                                      dtype=compute_type)
+    is_ep = expert_map is not None
+    expert_mask=None
+    ep_size=None
+    if is_ep:
+        expert_mask = torch.zeros((CHUNK_SIZE, top_k_num), dtype=torch.bool,  device=hidden_states.device, requires_grad=False)
+        ep_size = global_num_experts // E
+
+    if inplace:
+        out_hidden_states = hidden_states
+    else:
+        out_hidden_states = torch.empty_like(hidden_states, dtype=compute_type)
+
+    for chunk in range((num_tokens // CHUNK_SIZE) + 1):
+        begin_chunk_idx, end_chunk_idx = (chunk * CHUNK_SIZE,
+                                          min((chunk + 1) * CHUNK_SIZE,
+                                              num_tokens))
+        curr_hidden_states = hidden_states[begin_chunk_idx:end_chunk_idx]
+        tokens_in_chunk, _ = curr_hidden_states.shape
+
+        if tokens_in_chunk == 0:
+            break
+        
+        
+        bs = tokens_in_chunk
+        if num_local_tokens is not None and expect_m != -1:
+            bs = expect_m
+
+        intermediate_cache3 = intermediate_cache3.view(-1, K)
+        if tokens_in_chunk < CHUNK_SIZE and chunk > 0:
+            # Adjust the intermediate cache size and config for the last
+            # chunk. Note that in most cases we only have one chunk
+            # so the cache size and config are already set correctly and
+            # do not need to be adjusted.
+            intermediate_cache1 = intermediate_cache1[:tokens_in_chunk * top_k_num]
+            intermediate_cache2 = intermediate_cache2[:tokens_in_chunk * top_k_num]
+            intermediate_cache3 = intermediate_cache3[:tokens_in_chunk * top_k_num]
+        # import logging
+        # logger = logging.getLogger(__name__)
+        # if not status:
+        #     logger.info("lightop unsupport this size E:%s, N:%s, K:%s", E, N, K)
+        config_marlin_0, config_marlin_1, status = get_moe_cuda_marlin_config_w16a16(
+            E,
+            bs,
+            N2,
+            K,
+            K,
+            N,
+            top_k_num,
+            device_name,
+            num_cus,
+            hidden_states.dtype)
+        assert status, f'lightop unsupport this size E:{E}, N:{N}, K:{K}'
+        # Align with vLLM's default config handling for W16A16.
+        # if "BLOCK_SIZE_M" not in config_marlin_0:
+        #     config_marlin_0["BLOCK_SIZE_M"] = 16
+        # if "BLOCK_SIZE_M" not in config_marlin_1:
+        #     config_marlin_1["BLOCK_SIZE_M"] = config_marlin_0["BLOCK_SIZE_M"]
+        # if "MODE" not in config_marlin_0:
+        #     config_marlin_0["MODE"] = 412
+        # if "MODE" not in config_marlin_1:
+        #     config_marlin_1["MODE"] = 411
+        # if "DELTA" not in config_marlin_0:
+        #     config_marlin_0["DELTA"] = 1
+        # if "DELTA" not in config_marlin_1:
+        #     config_marlin_1["DELTA"] = 1
+
+        block_size_m = config_marlin_0["BLOCK_SIZE_M"]
+
+        curr_topk_ids = topk_ids[begin_chunk_idx:end_chunk_idx]
+        curr_topk_weights = topk_weights[begin_chunk_idx:end_chunk_idx]
+
+        if num_local_tokens is None:
+            sorted_token_ids, expert_ids, num_tokens_post_padded = (
+                moe_align_block_size(curr_topk_ids, block_size_m,
+                                    global_num_experts, expert_map=expert_map,
+                                    expert_mask = expert_mask[:tokens_in_chunk] if is_ep else None))
+        else:
+            sorted_token_ids, expert_ids, num_tokens_post_padded = (
+                moe_align_block_size_lightop(curr_topk_ids, block_size_m, global_num_experts, 
+                                            expert_map = expert_map, 
+                                            expert_mask = expert_mask[begin_chunk_idx:end_chunk_idx] if is_ep else None,
+                                            num_local_tokens = num_local_tokens,
+                                            ep_size=ep_size))
+
+        # GEMM1: hidden_states * w1 -> intermediate_cache1
+        moe_gemm_marlin_w16a16(
+            curr_hidden_states,
+            w1_marlin,
+            intermediate_cache1,
+            None,
+            sorted_token_ids,
+            expert_ids,
+            num_tokens_post_padded,
+            top_k_num,
+            config_marlin_0,
+        )
+        if (envs.VLLM_USE_FUSE_SILU_AND_MUL
+                and intermediate_cache1.dtype == intermediate_cache2.dtype
+                == torch.float16):
+            from lightop import fuse_silu_and_mul
+            fuse_silu_and_mul(intermediate_cache1, intermediate_cache2)
+        else:
+            torch.ops._C.silu_and_mul(intermediate_cache2, intermediate_cache1)
+
+        # GEMM2: intermediate_cache2 * w2, apply routing weights here.
+        moe_gemm_marlin_w16a16(
+            intermediate_cache2,
+            w2_marlin,
+            intermediate_cache3,
+            curr_topk_weights,
+            sorted_token_ids,
+            expert_ids,
+            num_tokens_post_padded,
+            1,
+            config_marlin_1,
+        )
+        intermediate_cache3 = intermediate_cache3.view(-1, top_k_num, K)
+
+        if envs.VLLM_USE_LIGHTOP_MOE_SUM_MUL_ADD: 
+            from lightop import op as op
+            op.moe_sum(input=intermediate_cache3.view(*intermediate_cache3.size()),
+                    output=out_hidden_states[begin_chunk_idx:end_chunk_idx], bias=shared_output[begin_chunk_idx:end_chunk_idx], 
+                    expert_mask=None, num_local_tokens=None, factor=routed_scaling_factor)
+        else:
+            if envs.VLLM_USE_LIGHTOP_MOE_SUM:
+                from lightop import op as op
+                op.moe_sum(input=intermediate_cache3.view(*intermediate_cache3.size()),
+                    output=out_hidden_states[begin_chunk_idx:end_chunk_idx], bias=None, 
+                    expert_mask=None, num_local_tokens=None, factor=1.0)
+            elif envs.VLLM_USE_OPT_MOE_SUM:
+                moe_reduce_dispatch(intermediate_cache3.view(*intermediate_cache3.size()), out_hidden_states[begin_chunk_idx:end_chunk_idx], begin_chunk_idx, end_chunk_idx)
+            else:
+                ops.moe_sum(intermediate_cache3.view(*intermediate_cache3.size()),
+                                out_hidden_states[begin_chunk_idx:end_chunk_idx])
+
+    return out_hidden_states

vllm/model_executor/layers/fused_moe/marlin_quant.py

+
+import torch
+import numpy as np
+
+# 从 [32, 64] int32的size中，重排后 每行相邻的8个uint4数据 混排后 pack成uint32数据
+
+#原本是32 * 16算一次mmac，因为npack组成32 * 64大小
+#现在是16 * 16算一次mmac，因为npack组成16 * 32大小
+#这里是在对32 * 64 进行数据的重排 
+
+def get_weight_perms(interleave: bool=False):
+    # ================== 4条mmac 指令进行拼接的结果 ============
+    perm = []
+    for i in range(64): # 遍历64个线程，因为是针对一个warp内的
+
+        for col in range(2): # 遍历列方向2次， 代表2次mmac指令 具体是行还是列还不知道
+
+            cur_col = (i % 16) * 2 + col  #计算当前线程在哪个列 这里是占据4列
+
+            for row in range(4): # 每个线程在 每个mmac中需要取8个uint4数据 占据8行
+                cur_row = (i // 16) * 4 + row
+                # 计算在整个 [32, 64]范围内的实际偏移
+                cur_idx =  cur_row * 32 + cur_col
+                perm.append(cur_idx)
+
+    perm = np.array(perm)
+    if interleave:
+        # =================  加入混排策略 =================
+        # # interleave = np.array([4, 0, 5, 1, 6, 2, 7, 3])
+        # # interleave = np.array([0, 4, 1, 5, 2, 6, 3, 7])
+        # QQQ 类似的 pack混排策略
+        interleave = np.array([4, 0, 5, 1, 6, 2, 7, 3])
+        # 按照 interleave 重排后展成 一维数组
+        perm = perm.reshape((-1, 8))[:, interleave].ravel()
+    
+    perm = torch.from_numpy(perm)
+
+    return perm
+
+#npack重排 //512大小
+def marlin_weights_npack2(
+                    q_w,
+                    weight_perm,
+                    k_tile=16,
+                    n_tile=32):
+    # 2048, 768
+    size_k, size_n = q_w.shape
+
+    # [7168, 512] ==> [128, 16, 24，32]
+    q_w = q_w.reshape((size_k // k_tile, k_tile, size_n // n_tile, n_tile))
+    # [128, 16, 24，32] ==> [128, 24, 16，32]
+    q_w = q_w.permute((0, 2, 1, 3))
+    # [128, 24, 16，32] ==> [128, 12288]
+    q_w = q_w.reshape((size_k // k_tile, size_n * k_tile))
+    # 按照指定的 perm进行重排
+    q_w = q_w.reshape((-1, weight_perm.numel()))[:, weight_perm].reshape(q_w.shape)
+
+    # orig_device = q_w.device
+
+    # q_w = q_w.cpu().numpy()
+    # q_packed = np.zeros((q_w.shape[0], q_w.shape[1] // pack_factor), dtype=np.uint32)
+    # for i in range(pack_factor):
+    #     q_packed |= q_w[:, i::pack_factor] << 4 * i
+    # q_packed = torch.from_numpy(q_packed.astype(np.int32)).to(orig_device)
+
+    return q_w
+
+def w16a16_marlin_weight(full_w16a16_w # [size_n, size_k]
+                        ):
+    # import pdb
+    # pdb.set_trace()
+    # [size_n, size_k] == > [size_k, size_n] 此时已经是默认NN的 k * n 基于这个进行重排
+    full_w16a16_w = full_w16a16_w.T
+    # 获取 [16, 32]的权重数据块中，需要重排的顺序
+    weight_perm = get_weight_perms()
+    # 按照索引进行重排
+    marlin_q_w = marlin_weights_npack2(full_w16a16_w, weight_perm, k_tile=16, n_tile=32)
+    return marlin_q_w

vllm/model_executor/models/qwen3_moe.py

@@ -57,6 +57,7 @@ from vllm.model_executor.models.utils import sequence_parallel_chunk
 from vllm.sequence import IntermediateTensors
 
 from .interfaces import MixtureOfExperts, SupportsLoRA, SupportsPP
+from vllm.utils import direct_register_custom_op
 from .utils import (AutoWeightsLoader, PPMissingLayer, extract_layer_index,
                     is_pp_missing_parameter,
                     make_empty_intermediate_tensors_factory, make_layers,
@@ -270,6 +271,59 @@ class Qwen3MoeAttention(nn.Module):
 
         self.q_norm = RMSNorm(self.head_dim, eps=rms_norm_eps)
         self.k_norm = RMSNorm(self.head_dim, eps=rms_norm_eps)
+    def rms_rotary_embedding_fuse(
+        positions: torch.Tensor,
+        query: torch.Tensor,
+        key: Optional[torch.Tensor],
+        head_size: int,
+        cos_sin_cache: torch.Tensor,
+        is_neox_style: bool,
+        q_weight: torch.Tensor,
+        k_weight: torch.Tensor,
+        q_bias: Optional[torch.Tensor],
+        k_bias: Optional[torch.Tensor],
+        epsilon: float,
+    ) -> None:
+        from lightop import rms_rotary_embedding_fuse as fused_kernel
+        fused_kernel(
+            positions,
+            query,
+            key,
+            head_size,
+            cos_sin_cache,
+            is_neox_style,
+            q_weight,
+            k_weight,
+            q_bias,
+            k_bias,
+            epsilon,
+        )
+
+    def rms_rotary_embedding_fuse_fake(
+        # q_out:torch.Tensor,
+        # k_out:torch.Tensor,
+        positions: torch.Tensor,
+        query: torch.Tensor,
+        key: Optional[torch.Tensor],
+        head_size: int,
+        cos_sin_cache: torch.Tensor,
+        is_neox_style: bool,
+        q_weight: torch.Tensor,
+        k_weight: torch.Tensor,
+        q_bias: Optional[torch.Tensor],
+        k_bias: Optional[torch.Tensor],
+        epsilon: float,
+    ) -> None:
+        # Fake impl intentionally left as no-op for graph tracing modes.
+        pass
+
+
+    direct_register_custom_op(
+        op_name="rms_rotary_embedding_fuse",
+        op_func=rms_rotary_embedding_fuse,
+        mutates_args=["query", "key"],
+        fake_impl=rms_rotary_embedding_fuse_fake,
+    )
 
     def forward(
         self,
@@ -279,6 +333,36 @@ class Qwen3MoeAttention(nn.Module):
         qkv, _ = self.qkv_proj(hidden_states)
         q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size], dim=-1)
         # Add qk-norm
+        if envs.VLLM_USE_FUSED_RMS_ROPE :
+            # Fused RMSNorm + RoPE path through custom op.
+            cos_sin_cache = self.rotary_emb.cos_sin_cache
+            if (cos_sin_cache.device != q.device
+                    or cos_sin_cache.dtype != q.dtype):
+                cos_sin_cache = cos_sin_cache.to(q.device,
+                                                 dtype=q.dtype,
+                                                 non_blocking=True)
+                # Persist the converted cache so we don't re-copy/re-allocate
+                # on every forward when the original buffer starts on CPU.
+                self.rotary_emb.cos_sin_cache = cos_sin_cache
+            # # q, k 使用 continuous
+            q = q.contiguous()
+            k = k.contiguous()
+            torch.ops.vllm.rms_rotary_embedding_fuse(
+                positions,
+                q,
+                k,
+                self.head_dim,
+                cos_sin_cache,
+                self.rotary_emb.is_neox_style,
+                self.q_norm.weight,
+                self.k_norm.weight,
+                None,
+                None,
+                self.q_norm.variance_epsilon,
+            )
+
+        else:
+            # Add qk-norm then RoPE (original path).
             q_by_head = q.view(*q.shape[:-1], q.shape[-1] // self.head_dim,
                                self.head_dim)
             if envs.VLLM_USE_APEX_RN: