[Feature] Qwen3-Next & FLA: Support MTP topk>1; Up to 6% faster (#11133)

Co-authored-by: Stefan He <hebiaobuaa@gmail.com>

python/sglang/srt/layers/attention/fla/fused_recurrent.py

@@ -330,12 +330,30 @@ def fused_recurrent_gated_delta_rule(
     return o, final_state
 
 
+# HAS_EAGLE_TREE_CUSTOM_ATTN_MASK is added to support eagle tree attention mask
+# retrieve_parent_token_ptr: [N, NP2_T], retrieve_next_sibling_ptr: [N, NP2_T]
+# e.g. for a sequence of length 4, the eagle tree attention structure is:
+# retrieve_next_token=[1, 3, -1, -1] -> retrieve_next_token[i]: the 1st child token of token i
+# retrieve_next_sibling=[-1, 2, -1, -1] -> retrieve_next_sibling[i]: the 1st tree sibling token of token i
+# retrieve_parent_token=[n/a, 0, 0, 1] -> retrieve_parent_token[i]: the parent token of token i
+# Tree:
+#    0
+#   / \
+#  1   2
+# /
+# 3
+# When calculating token 3's attention, it should attend to token 1 (parent) and token 0 (grand-parent)
+# When calculating token 2's attention, it should attend to token 0 (parent)
 @triton.heuristics(
     {
         "USE_INITIAL_STATE": lambda args: args["h0_source"] is not None,
         "IS_VARLEN": lambda args: args["cu_seqlens"] is not None,
         "CACHE_INTERMEDIATE_STATES": lambda args: args["intermediate_states_buffer"]
         is not None,
+        "HAS_EAGLE_TREE_CUSTOM_ATTN_MASK": lambda args: args[
+            "retrieve_parent_token_ptr"
+        ]
+        is not None,
     }
 )
 @triton.jit(do_not_specialize=["T"])
@@ -352,7 +370,11 @@ def fused_recurrent_gated_delta_rule_update_fwd_kernel(
     scale,
     intermediate_states_buffer,
     cache_steps,
+    retrieve_parent_token_ptr,
+    stride_retrieve_parent_token_seq: tl.constexpr,
+    stride_retrieve_parent_token_token: tl.constexpr,
     T,
+    NP2_T: tl.constexpr,
     B: tl.constexpr,
     H: tl.constexpr,
     HV: tl.constexpr,
@@ -367,6 +389,7 @@ def fused_recurrent_gated_delta_rule_update_fwd_kernel(
     DISABLE_STATE_UPDATE: tl.constexpr,  # whether to disable final state update
     DISABLE_OUTPUT_CALCULATION: tl.constexpr,  # whether to disable output calculation
     CACHE_INTERMEDIATE_STATES: tl.constexpr,
+    HAS_EAGLE_TREE_CUSTOM_ATTN_MASK: tl.constexpr,
 ):
     i_k, i_v, i_nh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
     i_n, i_hv = i_nh // HV, i_nh % HV
@@ -393,6 +416,16 @@ def fused_recurrent_gated_delta_rule_update_fwd_kernel(
     p_g = g + bos * HV + i_hv
     p_o = o + ((i_k * all + bos) * HV + i_hv) * V + o_v
 
+    if HAS_EAGLE_TREE_CUSTOM_ATTN_MASK:
+        token_indices = tl.arange(0, NP2_T)
+        mask_retrieve = token_indices < T
+        retrieve_parent_token_base = (
+            retrieve_parent_token_ptr
+            + (i_n * stride_retrieve_parent_token_seq)
+            + token_indices * stride_retrieve_parent_token_token
+        )
+        parent_idx_tokens = tl.load(retrieve_parent_token_base, mask_retrieve)
+
     mask_k = o_k < K
     mask_v = o_v < V
     mask_h = mask_k[:, None] & mask_v[None, :]
@@ -418,6 +451,24 @@ def fused_recurrent_gated_delta_rule_update_fwd_kernel(
 
     step_idx = 0
     for _ in range(0, T):
+        if HAS_EAGLE_TREE_CUSTOM_ATTN_MASK:
+            # step_idx = 0 should use the b_h from USE_INITIAL_STATE
+            if step_idx != 0 and cache_idx >= 0:
+                # when calculating current step's attention, load the state from the parent token
+                parent_step_idx = tl.sum(
+                    tl.where(token_indices == step_idx, parent_idx_tokens, 0)
+                )
+                step_offset = parent_step_idx * HV * K * V
+                cache_ptr = (
+                    intermediate_states_buffer
+                    + cache_idx * cache_steps * HV * K * V
+                    + step_offset
+                    + i_hv * K * V
+                    + o_k[:, None] * V
+                    + o_v[None, :]
+                )
+                b_h = tl.load(cache_ptr, mask=mask_h, other=0).to(tl.float32)
+
         b_q = tl.load(p_q, mask=mask_k, other=0).to(tl.float32)
         b_k = tl.load(p_k, mask=mask_k, other=0).to(tl.float32)
         b_v = tl.load(p_v, mask=mask_v, other=0).to(tl.float32)
@@ -498,6 +549,7 @@ def fused_recurrent_gated_delta_rule_update_fwd(
     disable_output_calculation: bool = False,
     intermediate_states_buffer: Optional[torch.Tensor] = None,
     cache_steps: Optional[int] = None,
+    retrieve_parent_token: Optional[torch.Tensor] = None,
 ) -> torch.Tensor:
     B, T, H, K, V = *k.shape, v.shape[-1]
     HV = v.shape[2]
@@ -516,6 +568,16 @@ def fused_recurrent_gated_delta_rule_update_fwd(
 
     grid = (NK, NV, N * HV)
 
+    # prepare retrieve next token buffer strides if provided
+    if retrieve_parent_token is not None:
+        stride_retrieve_parent_token_seq, stride_retrieve_parent_token_token = (
+            retrieve_parent_token.stride(0),
+            retrieve_parent_token.stride(1),
+        )
+    else:
+        stride_retrieve_parent_token_seq = stride_retrieve_parent_token_token = 0
+
+    NP2_T = triton.next_power_of_2(T)
     fused_recurrent_gated_delta_rule_update_fwd_kernel[grid](
         q=q,
         k=k,
@@ -529,7 +591,11 @@ def fused_recurrent_gated_delta_rule_update_fwd(
         scale=scale,
         intermediate_states_buffer=intermediate_states_buffer,
         cache_steps=0 if cache_steps is None else cache_steps,
+        retrieve_parent_token_ptr=retrieve_parent_token,
+        stride_retrieve_parent_token_seq=stride_retrieve_parent_token_seq,
+        stride_retrieve_parent_token_token=stride_retrieve_parent_token_token,
         T=T,
+        NP2_T=NP2_T,
         B=B,
         H=H,
         HV=HV,
@@ -568,6 +634,7 @@ class FusedRecurrentUpdateFunction(torch.autograd.Function):
         disable_output_calculation: bool = False,
         intermediate_states_buffer: Optional[torch.Tensor] = None,
         cache_steps: Optional[int] = None,
+        retrieve_parent_token: Optional[torch.Tensor] = None,
     ):
         o = fused_recurrent_gated_delta_rule_update_fwd(
             q=q,
@@ -584,6 +651,7 @@ class FusedRecurrentUpdateFunction(torch.autograd.Function):
             disable_output_calculation=disable_output_calculation,
             intermediate_states_buffer=intermediate_states_buffer,
             cache_steps=cache_steps,
+            retrieve_parent_token=retrieve_parent_token,
         )
 
         return o
@@ -613,6 +681,7 @@ def fused_recurrent_gated_delta_rule_update(
     disable_output_calculation: bool = False,
     intermediate_states_buffer: Optional[torch.Tensor] = None,
     cache_steps: Optional[int] = None,
+    retrieve_parent_token: Optional[torch.Tensor] = None,
 ) -> torch.Tensor:
     if cu_seqlens is not None:
         if q.shape[0] != 1:
@@ -649,5 +718,6 @@ def fused_recurrent_gated_delta_rule_update(
         disable_output_calculation,
         intermediate_states_buffer,
         cache_steps,
+        retrieve_parent_token,
     )
     return o

python/sglang/srt/layers/attention/hybrid_linear_attn_backend.py

@@ -66,12 +66,19 @@ class MambaAttnBackendBase(AttentionBackend):
         self.forward_metadata: ForwardMetadata = None
         self.state_indices_list = []
         self.query_start_loc_list = []
+        self.retrieve_next_token_list = []
+        self.retrieve_next_sibling_list = []
+        self.retrieve_parent_token_list = []
         self.cached_cuda_graph_decode_query_start_loc: torch.Tensor = None
         self.cached_cuda_graph_verify_query_start_loc: torch.Tensor = None
 
     def _forward_metadata(self, forward_batch: ForwardBatch):
         bs = forward_batch.batch_size
 
+        retrieve_next_token = None
+        retrieve_next_sibling = None
+        retrieve_parent_token = None
+
         if forward_batch.forward_mode.is_decode_or_idle():
             query_start_loc = torch.arange(
                 0, bs + 1, dtype=torch.int32, device=self.device
@@ -85,6 +92,11 @@ class MambaAttnBackendBase(AttentionBackend):
                     dtype=torch.int32,
                     device=forward_batch.input_ids.device,
                 )
+
+                if forward_batch.spec_info.topk > 1:
+                    retrieve_next_token = forward_batch.spec_info.retrive_next_token
+                    retrieve_next_sibling = forward_batch.spec_info.retrive_next_sibling
+                    retrieve_parent_token = torch.empty_like(retrieve_next_token)
             else:
                 query_start_loc = torch.empty(
                     (bs + 1,), dtype=torch.int32, device=self.device
@@ -102,6 +114,9 @@ class MambaAttnBackendBase(AttentionBackend):
         return ForwardMetadata(
             query_start_loc=query_start_loc,
             mamba_cache_indices=mamba_cache_indices,
+            retrieve_next_token=retrieve_next_token,
+            retrieve_next_sibling=retrieve_next_sibling,
+            retrieve_parent_token=retrieve_parent_token,
         )
 
     def init_forward_metadata(self, forward_batch: ForwardBatch):
@@ -118,7 +133,7 @@ class MambaAttnBackendBase(AttentionBackend):
         spec_info: Optional[Union[EagleDraftInput, EagleVerifyInput]],
     ):
         self.forward_metadata = self._capture_metadata(
-            bs, req_pool_indices, forward_mode
+            bs, req_pool_indices, forward_mode, spec_info
         )
 
     def init_forward_metadata_replay_cuda_graph(
@@ -140,7 +155,7 @@ class MambaAttnBackendBase(AttentionBackend):
         assert (
             max_num_tokens % max_bs == 0
         ), f"max_num_tokens={max_num_tokens} must be divisible by max_bs={max_bs}"
-        verify_step = max_num_tokens / max_bs
+        draft_token_num = max_num_tokens // max_bs
         for i in range(max_bs):
             self.state_indices_list.append(
                 torch.full(
@@ -150,19 +165,38 @@ class MambaAttnBackendBase(AttentionBackend):
             self.query_start_loc_list.append(
                 torch.empty((i + 2,), dtype=torch.int32, device=self.device)
             )
+            self.retrieve_next_token_list.append(
+                torch.zeros(
+                    (i + 1, draft_token_num), dtype=torch.int32, device=self.device
+                )
+            )
+            self.retrieve_next_sibling_list.append(
+                torch.zeros(
+                    (i + 1, draft_token_num), dtype=torch.int32, device=self.device
+                )
+            )
+            self.retrieve_parent_token_list.append(
+                torch.zeros(
+                    (i + 1, draft_token_num), dtype=torch.int32, device=self.device
+                )
+            )
         self.cached_cuda_graph_decode_query_start_loc = torch.arange(
             0, max_bs + 1, dtype=torch.int32, device=self.device
         )
         self.cached_cuda_graph_verify_query_start_loc = torch.arange(
             0,
-            max_bs * verify_step + 1,
+            max_bs * draft_token_num + 1,
-            step=verify_step,
+            step=draft_token_num,
             dtype=torch.int32,
             device=self.device,
         )
 
     def _capture_metadata(
-        self, bs: int, req_pool_indices: torch.Tensor, forward_mode: ForwardMode
+        self,
+        bs: int,
+        req_pool_indices: torch.Tensor,
+        forward_mode: ForwardMode,
+        spec_info: Optional[Union[EagleDraftInput, EagleVerifyInput]],
     ):
         if forward_mode.is_decode_or_idle():
             self.query_start_loc_list[bs - 1].copy_(
@@ -176,10 +210,24 @@ class MambaAttnBackendBase(AttentionBackend):
             raise ValueError(f"Invalid forward mode: {forward_mode=}")
         mamba_indices = self.req_to_token_pool.get_mamba_indices(req_pool_indices)
         self.state_indices_list[bs - 1][: len(mamba_indices)].copy_(mamba_indices)
-        return ForwardMetadata(
+
-            query_start_loc=self.query_start_loc_list[bs - 1],
+        # If topk > 1, we need to use retrieve_next_token and retrieve_next_sibling to handle the eagle tree custom attention mask
-            mamba_cache_indices=self.state_indices_list[bs - 1],
+        if forward_mode.is_target_verify() and spec_info.topk > 1:
-        )
+            # They are None during cuda graph capture so skip the copy_...
+            # self.retrieve_next_token_list[bs - 1].copy_(spec_info.retrive_next_token)
+            # self.retrieve_next_sibling_list[bs - 1].copy_(spec_info.retrive_next_sibling)
+            return ForwardMetadata(
+                query_start_loc=self.query_start_loc_list[bs - 1],
+                mamba_cache_indices=self.state_indices_list[bs - 1],
+                retrieve_next_token=self.retrieve_next_token_list[bs - 1],
+                retrieve_next_sibling=self.retrieve_next_sibling_list[bs - 1],
+                retrieve_parent_token=self.retrieve_parent_token_list[bs - 1],
+            )
+        else:
+            return ForwardMetadata(
+                query_start_loc=self.query_start_loc_list[bs - 1],
+                mamba_cache_indices=self.state_indices_list[bs - 1],
+            )
 
     def _replay_metadata(
         self,
@@ -224,10 +272,28 @@ class MambaAttnBackendBase(AttentionBackend):
         else:
             raise ValueError(f"Invalid forward mode: {forward_mode=}")
 
-        return ForwardMetadata(
+        # If topk > 1, we need to use retrieve_next_token and retrieve_next_sibling to handle the eagle tree custom attention mask
-            query_start_loc=self.query_start_loc_list[bs - 1],
+        if forward_mode.is_target_verify() and spec_info.topk > 1:
-            mamba_cache_indices=self.state_indices_list[bs - 1],
+            bs_without_pad = spec_info.retrive_next_token.shape[0]
-        )
+            # print(spec_info.retrive_next_token, spec_info.retrive_next_sibling)
+            self.retrieve_next_token_list[bs - 1][:bs_without_pad].copy_(
+                spec_info.retrive_next_token
+            )
+            self.retrieve_next_sibling_list[bs - 1][:bs_without_pad].copy_(
+                spec_info.retrive_next_sibling
+            )
+            return ForwardMetadata(
+                query_start_loc=self.query_start_loc_list[bs - 1],
+                mamba_cache_indices=self.state_indices_list[bs - 1],
+                retrieve_next_token=self.retrieve_next_token_list[bs - 1],
+                retrieve_next_sibling=self.retrieve_next_sibling_list[bs - 1],
+                retrieve_parent_token=self.retrieve_parent_token_list[bs - 1],
+            )
+        else:
+            return ForwardMetadata(
+                query_start_loc=self.query_start_loc_list[bs - 1],
+                mamba_cache_indices=self.state_indices_list[bs - 1],
+            )
 
     def get_cuda_graph_seq_len_fill_value(self):
         return 1  # Mamba attn does not use seq lens to index kv cache
@@ -557,6 +623,9 @@ class GDNAttnBackend(MambaAttnBackendBase):
 
         query_start_loc = self.forward_metadata.query_start_loc
         cache_indices = self.forward_metadata.mamba_cache_indices
+        retrieve_next_token = self.forward_metadata.retrieve_next_token
+        retrieve_next_sibling = self.forward_metadata.retrieve_next_sibling
+        retrieve_parent_token = self.forward_metadata.retrieve_parent_token
 
         mamba_cache_params = self.req_to_token_pool.mamba2_layer_cache(layer_id)
         conv_states = mamba_cache_params.conv
@@ -591,6 +660,9 @@ class GDNAttnBackend(MambaAttnBackendBase):
                 activation,
                 conv_state_indices=cache_indices[:batch_size],
                 intermediate_conv_window=intermediate_conv_window_cache,
+                retrieve_next_token=retrieve_next_token,
+                retrieve_next_sibling=retrieve_next_sibling,
+                retrieve_parent_token=retrieve_parent_token,
             )
             mixed_qkv = (
                 mixed_qkv_processed.transpose(1, 2).contiguous().view(seq_len, -1)
@@ -645,6 +717,7 @@ class GDNAttnBackend(MambaAttnBackendBase):
                 disable_state_update=True,
                 intermediate_states_buffer=intermediate_state_cache,
                 cache_steps=forward_batch.spec_info.draft_token_num,
+                retrieve_parent_token=retrieve_parent_token,
             )
         else:
             recurrent_state = ssm_states[cache_indices]
@@ -694,7 +767,7 @@ class Mamba2AttnBackend(MambaAttnBackendBase):
         forward_mode: ForwardMode,
         spec_info: Optional[Union[EagleDraftInput, EagleVerifyInput]],
     ):
-        metadata = self._capture_metadata(bs, req_pool_indices, forward_mode)
+        metadata = self._capture_metadata(bs, req_pool_indices, forward_mode, spec_info)
         self.forward_metadata = Mamba2Metadata.prepare_decode(
             metadata.query_start_loc, metadata.mamba_cache_indices, seq_lens
         )
@@ -891,8 +964,8 @@ class HybridLinearAttnBackend(AttentionBackend):
                 **kwargs,
             )
 
-    def update_mamba_state_after_mtp_verify(self, accepted_length, model):
+    def update_mamba_state_after_mtp_verify(self, accepted_indices, model):
-        request_number = accepted_length.shape[0]
+        request_number = accepted_indices.shape[0]
 
         state_indices_tensor = (
             self.linear_attn_backend.forward_metadata.mamba_cache_indices[
@@ -910,12 +983,11 @@ class HybridLinearAttnBackend(AttentionBackend):
         intermediate_conv_window_cache = mamba_caches.intermediate_conv_window
 
         # SSM state updates (chunked to reduce peak memory)
-        valid_mask = accepted_length > 0
+        valid_mask = accepted_indices >= 0
 
         # Compute common indices once to avoid duplication
-        last_steps_all = (accepted_length - 1).to(torch.int64)
         valid_state_indices = state_indices_tensor[valid_mask].to(torch.int64)  # [N]
-        last_steps = last_steps_all[valid_mask].to(torch.int64)  # [N]
+        last_steps = accepted_indices[valid_mask].to(torch.int64)  # [N]
 
         # scatter into ssm_states at the chosen cache lines
         ssm_states[:, valid_state_indices, :] = intermediate_state_cache[

python/sglang/srt/layers/attention/mamba/causal_conv1d_triton.py

@@ -186,7 +186,7 @@ def _causal_conv1d_fwd_kernel(  # continuous batching
             )
 
             mask = (idx_tokens_conv < state_len)[:, None] & (idx_feats < dim)[None, :]
-            tl.debug_barrier()  #  NOTE: use this due to bug in Triton compiler
+            # tl.debug_barrier()  #  NOTE: use this due to bug in Triton compiler
             tl.store(conv_states_ptrs_target, new_conv_state, mask)
 
         else:
@@ -221,7 +221,7 @@ def _causal_conv1d_fwd_kernel(  # continuous batching
                 )  # token-index  # token-index  # feature-index
                 loaded_x = tl.load(x_ptrs, mask_x, 0.0)
 
-                tl.debug_barrier()  # need this due to the bug in tl.where not enforcing this when data is the result of another tl.load
+                # tl.debug_barrier()  # need this due to the bug in tl.where not enforcing this when data is the result of another tl.load
                 new_conv_state = tl.where(
                     mask, conv_state, loaded_x
                 )  # BUG in 'tl.where'  which requires a barrier before this
@@ -552,6 +552,21 @@ def causal_conv1d_fn(
     return out
 
 
+# HAS_EAGLE_TREE_CUSTOM_ATTN_MASK is added to support eagle tree attention mask
+# retrieve_next_token_ptr: [N, NP2_T], retrieve_next_sibling_ptr: [N, NP2_T]
+# e.g. for a sequence of length 4, the eagle tree attention structure is:
+# retrieve_next_token=[1, 3, -1, -1] -> retrieve_next_token[i]: the 1st child token of token i
+# retrieve_next_sibling=[-1, 2, -1, -1] -> retrieve_next_sibling[i]: the 1st tree sibling token of token i
+# retrieve_parent_token=[n/a, 0, 0, 1] -> retrieve_parent_token[i]: the parent token of token i
+# Tree:
+#    0
+#   / \
+#  1   2
+# /
+# 3
+# When calculating token 3's convolution, it should conv to token 1 (parent) and token 0 (grand-parent)
+# When calculating token 2's convolution, it should conv to token 0 (parent)
+# This kernel is a fused kernel which will also produce retrieve_parent_token based on retrieve_next_token & retrieve_next_sibling
 @triton.jit()
 def _causal_conv1d_update_kernel(
     # Pointers to matrices
@@ -563,6 +578,9 @@ def _causal_conv1d_update_kernel(
     conv_state_indices_ptr,
     num_accepted_tokens_ptr,
     intermediate_conv_window_ptr,
+    retrieve_next_token_ptr,
+    retrieve_next_sibling_ptr,
+    retrieve_parent_token_ptr,
     o_ptr,  # (batch, dim, seqlen)
     # Matrix dimensions
     batch: int,
@@ -584,6 +602,12 @@ def _causal_conv1d_update_kernel(
     stride_inter_step: tl.constexpr,
     stride_inter_dim: tl.constexpr,
     stride_inter_win: tl.constexpr,
+    stride_retrieve_next_token_seq: tl.constexpr,
+    stride_retrieve_next_token_token: tl.constexpr,
+    stride_retrieve_next_sibling_seq: tl.constexpr,
+    stride_retrieve_next_sibling_token: tl.constexpr,
+    stride_retrieve_parent_token_seq: tl.constexpr,
+    stride_retrieve_parent_token_token: tl.constexpr,
     stride_o_seq: tl.constexpr,
     stride_o_dim: tl.constexpr,
     stride_o_token: tl.constexpr,
@@ -596,9 +620,11 @@ def _causal_conv1d_update_kernel(
     IS_CONTINUOUS_BATCHING: tl.constexpr,
     IS_SPEC_DECODING: tl.constexpr,
     NP2_STATELEN: tl.constexpr,
+    NP2_SEQLEN: tl.constexpr,
     USE_PAD_SLOT: tl.constexpr,
     BLOCK_N: tl.constexpr,
     SAVE_INTERMEDIATE: tl.constexpr,
+    HAS_EAGLE_TREE_CUSTOM_ATTN_MASK: tl.constexpr,
 ):
     # ruff: noqa: E501
     idx_seq = tl.program_id(0)
@@ -695,7 +721,7 @@ def _causal_conv1d_update_kernel(
         & (idx_feats < dim)[None, :]
     )  # token-index  # token-index  # feature-index
     loaded_x = tl.load(x_ptrs, mask_x, 0.0)
-    tl.debug_barrier()
+    # tl.debug_barrier()
 
     new_conv_state = tl.where(mask, conv_state, loaded_x)
 
@@ -723,6 +749,24 @@ def _causal_conv1d_update_kernel(
     # STEP 4:
     # PRE-LOAD WEIGHTS
     # first kernel column, configured for weights to handle BLOCK_N features in range
+    if HAS_EAGLE_TREE_CUSTOM_ATTN_MASK:
+        idx_tokens = tl.arange(0, NP2_SEQLEN)  # [BLOCK_M]
+        # Update parent mapping for all tokens at once using vectorized operations
+        mask_retrieve = idx_tokens < seqlen
+        retrieve_next_token_base = (
+            retrieve_next_token_ptr
+            + (idx_seq * stride_retrieve_next_token_seq)
+            + idx_tokens * stride_retrieve_next_token_token
+        )
+        retrieve_next_tokens = tl.load(retrieve_next_token_base, mask_retrieve)
+        retrieve_next_sibling_base = (
+            retrieve_next_sibling_ptr
+            + (idx_seq * stride_retrieve_next_sibling_seq)
+            + idx_tokens * stride_retrieve_next_sibling_token
+        )
+        retrieve_next_siblings = tl.load(retrieve_next_sibling_base, mask_retrieve)
+        parent_idx_tokens = tl.zeros((NP2_SEQLEN,), dtype=tl.int32)
+
     w_base = w_ptr + (idx_feats * stride_w_dim)  # [BLOCK_N,]
     mask_w = idx_feats < dim
     if KERNEL_WIDTH >= 2:
@@ -744,45 +788,162 @@ def _causal_conv1d_update_kernel(
     for idx_token in tl.static_range(seqlen):
         acc = acc_preload
 
-        matrix_w = w_col0
+        if HAS_EAGLE_TREE_CUSTOM_ATTN_MASK:
-        matrix_x = col0
+            # set the parent index of the next token in the eagle tree
-        for j in tl.static_range(KERNEL_WIDTH):
+            # next token's parent is the current token
+            retrieve_next_token_idx = tl.sum(
+                tl.where(idx_tokens == idx_token, retrieve_next_tokens, 0)
+            )
+            if retrieve_next_token_idx != -1:  # pad slot id
+                parent_idx_tokens = tl.where(
+                    idx_tokens == retrieve_next_token_idx,
+                    idx_token,
+                    parent_idx_tokens,
+                )
+            # next token's parent is the parent of the current token
+            retrieve_sibling_token_idx = tl.sum(
+                tl.where(idx_tokens == idx_token, retrieve_next_siblings, 0)
+            )
+            if retrieve_sibling_token_idx != -1:  # pad slot id
+                parent_idx_token = tl.sum(
+                    tl.where(idx_tokens == idx_token, parent_idx_tokens, 0)
+                )
+                parent_idx_tokens = tl.where(
+                    idx_tokens == retrieve_sibling_token_idx,
+                    parent_idx_token,
+                    parent_idx_tokens,
+                )
+            # tl.device_print("am", parent_idx_tokens)
+
+            _idx_token = idx_token
+            x_ptrs_1d = x_base_1d + _idx_token * stride_x_token  # [BLOCK_N]
+            matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
+            # convolution operation: itself * wcol[-1] + parent * wcol[-2] + grand-parent * wcol[-3] + ...
+            for j in tl.static_range(KERNEL_WIDTH):
+                if KERNEL_WIDTH == 2:
+                    if j == 0:
+                        matrix_w = w_col1
+                    else:
+                        matrix_w = w_col0
+                elif KERNEL_WIDTH == 3:
+                    if j == 0:
+                        matrix_w = w_col2
+                    elif j == 1:
+                        matrix_w = w_col1
+                    else:
+                        matrix_w = w_col0
+                elif KERNEL_WIDTH == 4:
+                    if j == 0:
+                        matrix_w = w_col3
+                    elif j == 1:
+                        matrix_w = w_col2
+                    elif j == 2:
+                        matrix_w = w_col1
+                    else:
+                        matrix_w = w_col0
+
+                if SAVE_INTERMEDIATE:
+                    # Save the window state after consuming this token
+                    # Layout: [seq(cache line), step, dim, win(K-1)]
+                    base_ptr = (
+                        intermediate_conv_window_ptr
+                        + conv_state_batch_coord * stride_inter_seq
+                        + idx_token * stride_inter_step
+                        + idx_feats * stride_inter_dim
+                    )
+
+                    # store itself in KERNEL_WIDTH-2 slot, parent in KERNEL_WIDTH-3 slot, grand-parent in KERNEL_WIDTH-4 slot, ...
+                    if KERNEL_WIDTH - j - 2 >= 0:
+                        tl.store(
+                            base_ptr + (KERNEL_WIDTH - j - 2) * stride_inter_win,
+                            matrix_x,
+                            mask=mask_w,
+                        )
+
+                acc += matrix_x * matrix_w
+
+                # move to parent for next iteration
+                if _idx_token > 0:
+                    _idx_token = tl.sum(
+                        tl.where(idx_tokens == _idx_token, parent_idx_tokens, 0)
+                    )
+                    x_ptrs_1d = x_base_1d + _idx_token * stride_x_token  # [BLOCK_N]
+                    matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
+                else:
+                    # no parent within the current chunk, load from prev conv state: col[-1] (idx 0's parent), col[-2] (idx 0's grand parent), ...
+                    if KERNEL_WIDTH == 2:
+                        if _idx_token == 0:
+                            matrix_x = col0
+                    elif KERNEL_WIDTH == 3:
+                        if _idx_token == 0:
+                            matrix_x = col1
+                        else:
+                            matrix_x = col0
+                    elif KERNEL_WIDTH == 4:
+                        if _idx_token == 0:
+                            matrix_x = col2
+                        elif _idx_token == -1:
+                            matrix_x = col1
+                        else:
+                            matrix_x = col0
+                    _idx_token = _idx_token - 1
+        else:
+            matrix_w = w_col0
+            matrix_x = col0
+
+            for j in tl.static_range(KERNEL_WIDTH):
+                if KERNEL_WIDTH == 2:
+                    if j == 1:  # KERNEL_WIDTH-1:
+                        matrix_w = w_col1
+                        x_ptrs_1d = x_base_1d + idx_token * stride_x_token  # [BLOCK_N]
+                        matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
+                elif KERNEL_WIDTH == 3:
+                    if j == 1:
+                        matrix_w = w_col1
+                        matrix_x = col1
+                    elif j == 2:
+                        matrix_w = w_col2
+                        x_ptrs_1d = x_base_1d + idx_token * stride_x_token  # [BLOCK_N]
+                        matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
+                elif KERNEL_WIDTH == 4:
+                    if j == 1:
+                        matrix_w = w_col1
+                        matrix_x = col1
+                    elif j == 2:
+                        matrix_w = w_col2
+                        matrix_x = col2
+                    elif j == 3:
+                        matrix_w = w_col3
+                        x_ptrs_1d = x_base_1d + idx_token * stride_x_token  # [BLOCK_N]
+                        matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
+
+                acc += matrix_x * matrix_w  # [BLOCK_N]
+
             if KERNEL_WIDTH == 2:
-                if j == 1:  # KERNEL_WIDTH-1:
+                col0 = matrix_x
-                    matrix_w = w_col1
-                    x_ptrs_1d = x_base_1d + idx_token * stride_x_token  # [BLOCK_N]
-                    matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
             elif KERNEL_WIDTH == 3:
-                if j == 1:
+                col0 = col1
-                    matrix_w = w_col1
+                col1 = matrix_x
-                    matrix_x = col1
-                elif j == 2:
-                    matrix_w = w_col2
-                    x_ptrs_1d = x_base_1d + idx_token * stride_x_token  # [BLOCK_N]
-                    matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
             elif KERNEL_WIDTH == 4:
-                if j == 1:
+                col0 = col1
-                    matrix_w = w_col1
+                col1 = col2
-                    matrix_x = col1
+                col2 = matrix_x
-                elif j == 2:
-                    matrix_w = w_col2
-                    matrix_x = col2
-                elif j == 3:
-                    matrix_w = w_col3
-                    x_ptrs_1d = x_base_1d + idx_token * stride_x_token  # [BLOCK_N]
-                    matrix_x = tl.load(x_ptrs_1d, mask=mask_x_1d)
 
-            acc += matrix_x * matrix_w  # [BLOCK_N]
+            if SAVE_INTERMEDIATE:
-
+                # Save the window state after consuming this token
-        if KERNEL_WIDTH == 2:
+                # Layout: [seq(cache line), step, dim, win(K-1)]
-            col0 = matrix_x
+                base_ptr = (
-        elif KERNEL_WIDTH == 3:
+                    intermediate_conv_window_ptr
-            col0 = col1
+                    + conv_state_batch_coord * stride_inter_seq
-            col1 = matrix_x
+                    + idx_token * stride_inter_step
-        elif KERNEL_WIDTH == 4:
+                    + idx_feats * stride_inter_dim
-            col0 = col1
+                )
-            col1 = col2
+                if KERNEL_WIDTH >= 2:
-            col2 = matrix_x
+                    tl.store(base_ptr + 0 * stride_inter_win, col0, mask=mask_w)
+                if KERNEL_WIDTH >= 3:
+                    tl.store(base_ptr + 1 * stride_inter_win, col1, mask=mask_w)
+                if KERNEL_WIDTH >= 4:
+                    tl.store(base_ptr + 2 * stride_inter_win, col2, mask=mask_w)
 
         if SILU_ACTIVATION:
             acc = acc / (1 + tl.exp(-acc))
@@ -798,21 +959,15 @@ def _causal_conv1d_update_kernel(
 
         tl.store(o_ptrs, acc, mask=mask_1d)
 
-        if SAVE_INTERMEDIATE:
+        # fuse: store calculated retrieve_parent_token to tensor
-            # Save the window state after consuming this token
+        if HAS_EAGLE_TREE_CUSTOM_ATTN_MASK:
-            # Layout: [seq(cache line), step, dim, win(K-1)]
+            tl.store(
-            base_ptr = (
+                retrieve_parent_token_ptr
-                intermediate_conv_window_ptr
+                + idx_seq * stride_retrieve_parent_token_seq
-                + conv_state_batch_coord * stride_inter_seq
+                + idx_tokens * stride_retrieve_parent_token_token,
-                + idx_token * stride_inter_step
+                parent_idx_tokens,
-                + idx_feats * stride_inter_dim
+                mask=mask_retrieve,
             )
-            if KERNEL_WIDTH >= 2:
-                tl.store(base_ptr + 0 * stride_inter_win, col0, mask=mask_w)
-            if KERNEL_WIDTH >= 3:
-                tl.store(base_ptr + 1 * stride_inter_win, col1, mask=mask_w)
-            if KERNEL_WIDTH >= 4:
-                tl.store(base_ptr + 2 * stride_inter_win, col2, mask=mask_w)
 
 
 def causal_conv1d_update(
@@ -825,6 +980,9 @@ def causal_conv1d_update(
     conv_state_indices: Optional[torch.Tensor] = None,
     num_accepted_tokens: Optional[torch.Tensor] = None,
     intermediate_conv_window: Optional[torch.Tensor] = None,
+    retrieve_next_token: Optional[torch.Tensor] = None,
+    retrieve_next_sibling: Optional[torch.Tensor] = None,
+    retrieve_parent_token: Optional[torch.Tensor] = None,
     pad_slot_id: int = PAD_SLOT_ID,
     metadata=None,
     validate_data=False,
@@ -888,7 +1046,7 @@ def causal_conv1d_update(
         assert cache_seqlens is None  # not needed for vLLM - circular buffer
 
     # adopt the strategy in vLLM that overwrite on 'x' directly, rather than creating a new tensor 'o'
-    out = x
+    out = torch.empty_like(x)
     stride_w_dim, stride_w_width = weight.stride()
 
     stride_x_seq, stride_x_dim, stride_x_token = x.stride()  # X (batch, dim, seqlen)
@@ -903,6 +1061,7 @@ def causal_conv1d_update(
     else:
         state_len = width - 1
     np2_statelen = triton.next_power_of_2(state_len)
+    np2_seqlen = triton.next_power_of_2(seqlen)
 
     def grid(META):
         return (
@@ -921,6 +1080,33 @@ def causal_conv1d_update(
     else:
         stride_inter_seq = stride_inter_step = stride_inter_dim = stride_inter_win = 0
 
+    # prepare retrieve next token buffer strides if provided
+    if retrieve_next_token is not None:
+        stride_retrieve_next_token_seq, stride_retrieve_next_token_token = (
+            retrieve_next_token.stride(0),
+            retrieve_next_token.stride(1),
+        )
+    else:
+        stride_retrieve_next_token_seq = stride_retrieve_next_token_token = 0
+
+    # prepare retrieve next sibling buffer strides if provided
+    if retrieve_next_sibling is not None:
+        stride_retrieve_next_sibling_seq, stride_retrieve_next_sibling_token = (
+            retrieve_next_sibling.stride(0),
+            retrieve_next_sibling.stride(1),
+        )
+    else:
+        stride_retrieve_next_sibling_seq = stride_retrieve_next_sibling_token = 0
+
+    # prepare retrieve parent token buffer strides if provided
+    if retrieve_parent_token is not None:
+        stride_retrieve_parent_token_seq, stride_retrieve_parent_token_token = (
+            retrieve_parent_token.stride(0),
+            retrieve_parent_token.stride(1),
+        )
+    else:
+        stride_retrieve_parent_token_seq = stride_retrieve_parent_token_token = 0
+
     _causal_conv1d_update_kernel[grid](
         # Pointers to matrices
         x,
@@ -931,6 +1117,9 @@ def causal_conv1d_update(
         conv_state_indices,
         num_accepted_tokens,
         intermediate_conv_window if intermediate_conv_window is not None else x,
+        retrieve_next_token,
+        retrieve_next_sibling,
+        retrieve_parent_token,
         out,
         # Matrix dimensions
         batch,
@@ -952,6 +1141,12 @@ def causal_conv1d_update(
         stride_inter_step,
         stride_inter_dim,
         stride_inter_win,
+        stride_retrieve_next_token_seq,
+        stride_retrieve_next_token_token,
+        stride_retrieve_next_sibling_seq,
+        stride_retrieve_next_sibling_token,
+        stride_retrieve_parent_token_seq,
+        stride_retrieve_parent_token_token,
         stride_o_seq,
         stride_o_dim,
         stride_o_token,
@@ -964,9 +1159,11 @@ def causal_conv1d_update(
         IS_CONTINUOUS_BATCHING=conv_state_indices is not None,
         IS_SPEC_DECODING=num_accepted_tokens is not None,
         NP2_STATELEN=np2_statelen,
+        NP2_SEQLEN=np2_seqlen,
         USE_PAD_SLOT=pad_slot_id is not None,
         BLOCK_N=256,
         SAVE_INTERMEDIATE=intermediate_conv_window is not None,
+        HAS_EAGLE_TREE_CUSTOM_ATTN_MASK=retrieve_next_token is not None,
     )
     if unsqueeze:
         out = out.squeeze(-1)

python/sglang/srt/layers/attention/mamba/mamba2_metadata.py

@@ -16,6 +16,7 @@
 
 import math
 from dataclasses import dataclass
+from typing import Optional
 
 import torch
 
@@ -26,6 +27,9 @@ from sglang.srt.model_executor.forward_batch_info import ForwardBatch
 class ForwardMetadata:
     query_start_loc: torch.Tensor
     mamba_cache_indices: torch.Tensor
+    retrieve_next_token: Optional[torch.Tensor] = None
+    retrieve_next_sibling: Optional[torch.Tensor] = None
+    retrieve_parent_token: Optional[torch.Tensor] = None
 
 
 @dataclass(kw_only=True)

python/sglang/srt/speculative/eagle_worker.py

@@ -694,19 +694,45 @@ class EAGLEWorker(TpModelWorker):
         ]
         logits_output.hidden_states = logits_output.hidden_states[res.accepted_indices]
 
-        # QQ: can be optimized
         if self.target_worker.model_runner.hybrid_gdn_config is not None:
-            # res.draft_input.accept_length is on GPU but may be empty for last verify?
             accepted_length = (
                 torch.tensor(
                     res.accept_length_per_req_cpu,
                     device=logits_output.hidden_states.device,
-                    dtype=torch.int32,
+                    dtype=torch.int64,
                 )
                 + 1
             )
+
+            # If topk > 1, we need to use retrieve_next_token and retrieve_next_sibling to handle the eagle tree custom attention mask
+            # res.accepted_indices.shape[0] > 0 skips DP attn idle batch
+            if spec_info.topk > 1 and res.accepted_indices.shape[0] > 0:
+                # accepted_indices=[0,2,3,4,5,7,9,10,11], accepted_length=[4, 3, 2], cumulative_accepted_lengths=[4, 7, 9]
+                # first_token_indices_per_req=prepend(0, accepted_indices[cumulative_accepted_lengths[:-1]]) = [0, 5, 10]
+                # last_token_indices_per_req=accepted_indices[cumulative_accepted_lengths - 1] = [4, 9, 11] (last token ID of each req)
+                # max_relative_indices_per_req = [4,4,1]; those are the per-req spec-decoding step offsets that contain the correct mamba caches
+                cumulative_accepted_lengths = torch.cumsum(accepted_length, dim=0)
+                req_start_positions = torch.cat(
+                    [
+                        torch.zeros(
+                            1,
+                            dtype=cumulative_accepted_lengths.dtype,
+                            device=cumulative_accepted_lengths.device,
+                        ),
+                        cumulative_accepted_lengths[:-1],
+                    ]
+                )
+                first_token_indices_per_req = res.accepted_indices[req_start_positions]
+                last_token_indices_per_req = res.accepted_indices[
+                    cumulative_accepted_lengths - 1
+                ]
+                max_relative_indices_per_req = (
+                    last_token_indices_per_req - first_token_indices_per_req
+                )
+            else:
+                max_relative_indices_per_req = accepted_length - 1
             self.target_worker.model_runner.attn_backend.update_mamba_state_after_mtp_verify(
-                accepted_length, self.target_worker.model_runner.model
+                max_relative_indices_per_req, self.target_worker.model_runner.model
             )
 
         if batch.return_logprob:

test/srt/models/test_qwen3_next_models.py

@@ -59,11 +59,56 @@ class TestQwen3NextMTP(CustomTestCase):
                 "--speculative-algorithm",
                 "NEXTN",
                 "--speculative-num-steps",
-                "1",
+                "3",
                 "--speculative-eagle-topk",
                 "1",
                 "--speculative-num-draft-tokens",
-                "2",
+                "4",
+                "--mem-fraction-static",
+                "0.8",
+                "--tp",
+                "4",
+            ],
+        )
+
+    @classmethod
+    def tearDownClass(cls):
+        kill_process_tree(cls.process.pid)
+
+    def test_gsm8k(self):
+        args = SimpleNamespace(
+            num_shots=5,
+            data_path=None,
+            num_questions=200,
+            max_new_tokens=512,
+            parallel=128,
+            host="http://127.0.0.1",
+            port=int(self.base_url.split(":")[-1]),
+        )
+        metrics = run_eval(args)
+        print(f"{metrics=}")
+        self.assertGreater(metrics["accuracy"], 0.93)
+
+
+class TestQwen3NextMTPTopk(CustomTestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.model = "Qwen/Qwen3-Next-80B-A3B-Instruct"
+        cls.base_url = DEFAULT_URL_FOR_TEST
+        cls.process = popen_launch_server(
+            cls.model,
+            cls.base_url,
+            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
+            other_args=[
+                "--trust-remote-code",
+                "--speculative-algorithm",
+                "NEXTN",
+                "--speculative-num-steps",
+                "5",
+                "--speculative-eagle-topk",
+                "4",
+                "--speculative-num-draft-tokens",
+                "8",
                 "--mem-fraction-static",
                 "0.8",
                 "--tp",