[AMD][DCP 1/N] add dcp support for aiter backend (#34432)

Co-authored-by: HAI <hixiao@gmail.com>

python/sglang/srt/arg_groups/model_overrides/kimi_k3.py

@@ -42,6 +42,16 @@ def _require_kimi_k3_cutedsl_dcp_support() -> None:
         )
 
 
+def _require_kimi_k3_aiter_gluon_dcp_support() -> None:
+    from sglang.srt.layers.attention.aiter_mla_gluon import _gluon_fn
+
+    if _gluon_fn() is None:
+        raise RuntimeError(
+            "Kimi-K3 DCP with decode_attention_backend='aiter' requires the aiter "
+            "gluon mla kernel, which is unavailable. See above aborting reasons."
+        )
+
+
 @_register_for("KimiK3ForConditionalGeneration")
 def _kimi_k3_overrides(server_args: Any, hf_config: Any) -> dict:
     cfg = resolving_view(server_args)
@@ -101,9 +111,23 @@ def _kimi_k3_overrides(server_args: Any, hf_config: Any) -> dict:
                 decode_attention_backend="tokenspeed_mla",
                 kv_cache_dtype="fp8_e4m3",
             )
+        elif decode_backend == "aiter":
+            _require_kimi_k3_aiter_gluon_dcp_support()
+            # Override prefill backend to aiter by default
+            # if users don't explicitly specify triton
+            prefill_ab = "triton" if prefill_backend == "triton" else "aiter"
+            logger.info(
+                "Kimi-K3 DCP uses aiter MLA decode: "
+                f"prefill={prefill_backend!r} -> {prefill_ab!r}, "
+                f"decode={decode_backend!r} -> 'aiter'."
+            )
+            overrides.update(
+                prefill_attention_backend=prefill_ab,
+                decode_attention_backend="aiter",
+            )
         else:
             raise AssertionError(
-                f"Decode attention backend for Kimi-K3 DCP must be 'cutedsl_mla' or 'tokenspeed_mla', got {decode_backend!r}."
+                f"Decode attention backend for Kimi-K3 DCP must be 'cutedsl_mla', 'tokenspeed_mla' or 'aiter', got {decode_backend!r}."
             )
 
         if cfg.dcp_replicate_q_proj is None:

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

@@ -26,6 +26,8 @@ from sglang.kernels.ops.kvcache.aiter_unified_attention import (
     scatter_req_to_token_to_page_table_kernel,
 )
 from sglang.srt.layers.attention.base_attn_backend import AttentionBackend
+from sglang.srt.layers.dcp import update_local_kv_lens_for_dcp
+from sglang.srt.layers.dcp.planner import plan_dcp_decode_metadata
 from sglang.srt.layers.dp_attention import is_dp_attention_enabled
 from sglang.srt.model_executor.forward_batch_info import ForwardBatch, ForwardMode
 from sglang.srt.speculative.spec_utils import (
@@ -67,6 +69,8 @@ except ImportError:
         "aiter is AMD specific kernel library. Please make sure aiter is installed on your AMD device."
     )
 
+from sglang.kernels.ops.attention.dcp_kernels import create_mla_kv_page_table_for_dcp
+from sglang.kernels.ops.attention.merge_state import merge_state_triton
 from sglang.kernels.ops.attention.utils import (
     launch_reshape_and_cache_flash,
     pad_sequence_with_mask,
@@ -151,11 +155,16 @@ class ForwardMetadata:
     swa_page_table: Optional[torch.Tensor] = None
     # full->SWA translated out_cache_loc (SWA KV-store write target)
     swa_out_cache_loc: Optional[torch.Tensor] = None
+    local_kv_lens: Optional[torch.Tensor] = None
+    verify_token_table: Optional[torch.Tensor] = None
 
 
 _AITER_PARTITION_SIZE_ROCM = 256
 
 
+_DCP_VERIFY_TABLE_COLS_PER_BLOCK = 128
+
+
 # AITER's gfx950 FP8 FMHA ASM kernels only cover these GQA ratios. Other
 # ratios (e.g. Qwen3.8-27B 24Q/4KV = 6) must not take the pertensor shortcut.
 _AITER_FP8_ASM_GQA_RATIOS = frozenset({1, 2, 4, 8, 16})
@@ -264,6 +273,8 @@ class AiterAttnBackend(AttentionBackend):
 
         self.use_mla = model_runner.model_config.attention_arch == AttentionArch.MLA
 
+        self.dcp_world_size = get_parallel().attn_dcp_size
+
         # Get v_head_dim based on model type
         if self.use_mla:
             # For MLA models, get v_head_dim from model config
@@ -348,6 +359,7 @@ class AiterAttnBackend(AttentionBackend):
         # corresponding ForwardBatch fields.
         self.req_to_token_pool = model_runner.req_to_token_pool
         self.token_to_kv_pool = model_runner.token_to_kv_pool
+        self.kv_index_translator = model_runner.kv_index_translator
 
         # sliding window attention. Resolve the SWA pool rather than reading it
         # straight off the active pool: a frozen-KV MTP draft worker's active
@@ -433,13 +445,19 @@ class AiterAttnBackend(AttentionBackend):
             # _mla_decode_fwd_with_head_pad brings any count below 16 up to it,
             # by repetition when it divides 16 and by tiling otherwise.
             _pad_heads_to_16 = self.num_head < 16
-            assert _valid_heads or _pad_heads_to_16 or not may_run_mla_decode, (
+            assert (
+                self.dcp_world_size > 1
+                or _valid_heads
+                or _pad_heads_to_16
+                or not may_run_mla_decode
+            ), (
                 f"Aiter MLA supports num_head of 4, 8, 12, or multiples of 16 "
                 f"in [16, 128].\n"
                 f"Provided {self.num_head} number of heads.\n"
                 "Try adjusting tensor_parallel_size value, or run decode on "
                 "another backend (--decode-attention-backend)."
             )
+
             self.num_head_padded = 16 if self.num_head < 16 else self.num_head
             if self.num_head in _mla_low_head_repeat:
                 self.head_pad_mode = "repeat"
@@ -451,17 +469,22 @@ class AiterAttnBackend(AttentionBackend):
                 self.head_pad_mode = "none"
                 self.head_repeat_factor = 1
 
+            _gathered_num_head = self.num_head * self.dcp_world_size
+            self.mla_kernel_num_head_padded = (
+                16 if _gathered_num_head < 16 else _gathered_num_head
+            )
+
             self.enable_dp_attention = is_dp_attention_enabled()
             self.qo_indptr_ = torch.zeros(
                 (max_bs + 1,), dtype=torch.int32, device=model_runner.device
             )
             global _use_mla_ps_kernel, fast_mode, intra_batch_mode
 
-            # current mla_decode_fwd only support fake-nps in self.num_head == 16
+            # current mla_decode_fwd only support fake-nps in num_head == 16
             # so all num_head size does not use qh16 kernel to simulate
             # it should not use fake-nps (fast_mode = False, intra_batch_mode = True)
-            # it will cause gpu-fault or accuracy issue
-            if self.num_head in (32, 64, 128):
+            # it will cause gpu-fault or accuracy issue.
+            if self.mla_kernel_num_head_padded in (32, 64, 128):
                 fast_mode = True
                 intra_batch_mode = False
 
@@ -473,8 +496,8 @@ class AiterAttnBackend(AttentionBackend):
             # Native 16-head persist is slow on TP8; keep disabled unless zero-pad
             # (e.g. Kimi K3 h12 -> qh16) where persist ASM is the fast path.
             if (
-                (self.num_head_padded == 16 and self.head_pad_mode != "zero")
-                or self.num_head_padded == 128
+                (self.mla_kernel_num_head_padded == 16 and self.head_pad_mode != "zero")
+                or self.mla_kernel_num_head_padded == 128
             ) and self.kv_cache_dtype is not fp8_dtype:
                 _use_mla_ps_kernel = False
                 fast_mode = False
@@ -551,7 +574,7 @@ class AiterAttnBackend(AttentionBackend):
         return "fp8_e4m3"
 
     def make_mla_decode_meta_data_buffer(self, max_seqlen_qo, batch_size):
-        nhead = self.num_head_padded
+        nhead = self.mla_kernel_num_head_padded
         dtype = self.kv_cache_dtype
 
         if self.enable_dp_attention:
@@ -637,7 +660,7 @@ class AiterAttnBackend(AttentionBackend):
             qo_indptr,
             kv_indptr,
             kv_last_page_len,
-            self.num_head_padded // nhead_kv,
+            self.mla_kernel_num_head_padded // nhead_kv,
             nhead_kv,
             False,
             work_metadata,
@@ -1084,6 +1107,80 @@ class AiterAttnBackend(AttentionBackend):
             num_kv_splits=num_kv_splits,
         )
 
+    def _get_dcp_graph_max_local_kv_len(self) -> int:
+        """Static upper bound on this rank's shard, ceil(max_context_len / W)."""
+        w = max(self.dcp_world_size, 1)
+        return (self.max_context_len + w - 1) // w
+
+    def _forward_decode_dcp(self, q, k_buffer, layer, k_descale):
+        """Attend this rank's KV shard for decode -> (out, natural-log lse)."""
+        fm = self.forward_metadata
+        bs = fm.kv_indptr.shape[0] - 1
+        num_heads = layer.tp_q_head_num  # gathered heads = num_local_heads * dcp
+
+        out, lse = mla_gluon_decode(
+            q=q.view(bs, num_heads, layer.qk_head_dim),
+            k_buffer=k_buffer,
+            layer=layer,
+            kv_indices=fm.kv_indices,
+            kv_indptr=fm.kv_indptr[: bs + 1],
+            sm_scale=layer.scaling,
+            kv_scale=self._resolve_fp8_kv_scale_float(layer, k_descale),
+            min_kv_seq_len=1,
+            return_lse=True,
+        )
+        return out, lse.view(bs, num_heads)
+
+    def _forward_verify_dcp(self, q, k_window, layer, k_descale):
+        """Attend the committed prefix and the verify window separately, then
+        merge -> (out, natural-log lse).
+
+        Splitting at the window boundary avoids the one thing the decode kernel
+        cannot do under DCP: mask on the GLOBAL position g(j) = j * W + r.
+        """
+        fm = self.forward_metadata
+        q_len = fm.max_q_len
+        num_heads = layer.tp_q_head_num  # gathered heads = num_local_heads * dcp
+        seqused_k = fm.local_kv_lens
+        n_rows = seqused_k.shape[0]
+        bs = n_rows // q_len
+
+        out_a, lse_a = mla_gluon_decode(
+            q=q.view(n_rows, num_heads, layer.qk_head_dim),
+            k_buffer=self.token_to_kv_pool.get_key_buffer(layer.layer_id),
+            layer=layer,
+            kv_indices=fm.verify_token_table,
+            kv_indptr=seqused_k,
+            sm_scale=layer.scaling,
+            kv_scale=self._resolve_fp8_kv_scale_float(layer, k_descale),
+            min_kv_seq_len=1,
+            return_lse=True,
+            use_2d_view=True,
+        )
+        lse_a = lse_a.view(n_rows, num_heads)
+
+        # The verify window arrives as `k_window`, computed this forward and
+        # identical on every rank, so only one rank attends it; the others
+        # return their prefix partial for the cross-rank merge.
+        if get_parallel().attn_dcp_rank != 0:
+            return out_a, lse_a
+
+        # The window latent is request-major and contiguous, so it IS the pool:
+        # row i of request b lives at b * q_len + i. mla_gluon's MTP mask at
+        # seq_len == qlen is exactly the dense causal window this needs.
+        out_b, lse_b = mla_gluon_decode(
+            q=q.view(n_rows, num_heads, layer.qk_head_dim),
+            k_buffer=k_window,
+            layer=layer,
+            kv_indices=torch.arange(n_rows, dtype=torch.int32, device=q.device),
+            kv_indptr=torch.arange(bs + 1, dtype=torch.int32, device=q.device) * q_len,
+            sm_scale=layer.scaling,
+            min_kv_seq_len=1,
+            qlen=q_len,
+            return_lse=True,
+        )
+        return merge_state_triton(out_a, lse_a, out_b, lse_b.view(n_rows, num_heads))
+
     def mla_fp8_prefill_attn(
         self,
         q: torch.Tensor,
@@ -1243,6 +1340,9 @@ class AiterAttnBackend(AttentionBackend):
             )
         max_kv_len = forward_batch.seq_lens_cpu.max().item()
 
+        # dcp metadata
+        local_kv_lens = None
+        verify_token_table = None
         if forward_batch.forward_mode.is_decode_or_idle():
             if spec_info is None or forward_batch.forward_mode.is_idle():
                 kv_indptr[1 : bs + 1] = torch.cumsum(forward_batch.seq_lens, dim=0)
@@ -1261,6 +1361,20 @@ class AiterAttnBackend(AttentionBackend):
                         kv_indices,
                         self.req_to_token.stride(0),
                     )
+
+                    if (
+                        self.use_mla
+                        and self.dcp_world_size > 1
+                        and not forward_batch.forward_mode.is_idle()
+                    ):
+                        kv_lens = forward_batch.seq_lens[:bs].to(torch.int32).clone()
+                        self._plan_dcp_decode_metadata(
+                            kv_indptr,
+                            kv_indices,
+                            kv_lens,
+                            forward_batch.seq_lens_cpu,
+                            bs,
+                        )
                 else:
                     max_q_len = 1
                     page_size = self.page_size
@@ -1317,7 +1431,9 @@ class AiterAttnBackend(AttentionBackend):
                 kv_last_page_len = self.kv_last_page_len[:bs]
                 max_q_len = 1
 
-                if _use_mla_ps_kernel:
+                # DCP decode runs the aiter MLA kernel (builds its own block-table
+                # metadata in forward_decode), so skip the persist metadata.
+                if _use_mla_ps_kernel and self.dcp_world_size <= 1:
                     (
                         work_metadata,
                         work_indptr,
@@ -1456,9 +1572,13 @@ class AiterAttnBackend(AttentionBackend):
         elif forward_batch.forward_mode.is_target_verify():
             if self.use_mla:
                 draft_num = spec_info.draft_token_num
-                kv_lens = forward_batch.seq_lens + draft_num
-                kv_lens_sum = forward_batch.seq_lens_sum + draft_num * bs
                 device = forward_batch.seq_lens.device
+                if self.dcp_world_size > 1:
+                    kv_lens = forward_batch.seq_lens.to(torch.int32).clone()
+                    kv_lens_sum = forward_batch.seq_lens_sum
+                else:
+                    kv_lens = forward_batch.seq_lens + draft_num
+                    kv_lens_sum = forward_batch.seq_lens_sum + draft_num * bs
 
                 qo_indptr = self.qo_indptr[: bs + 1]
                 qo_indptr[: bs + 1] = torch.arange(
@@ -1486,8 +1606,26 @@ class AiterAttnBackend(AttentionBackend):
                     TOKEN_BLOCK_PARALLEL=num_token_blocks > 1,
                 )
 
-                # if self.kv_cache_dtype == fp8_dtype:
-                if _use_mla_ps_kernel:
+                if self.dcp_world_size > 1:
+                    self._plan_dcp_decode_metadata(
+                        kv_indptr,
+                        kv_indices,
+                        kv_lens,
+                        None,
+                        bs,
+                    )
+                    (
+                        verify_token_table,
+                        local_kv_lens,
+                    ) = self._build_dcp_verify_token_table(
+                        kv_indptr,
+                        forward_batch.req_pool_indices,
+                        bs,
+                        draft_num,
+                        (max_kv_len + self.dcp_world_size - 1) // self.dcp_world_size,
+                    )
+
+                if _use_mla_ps_kernel and self.dcp_world_size <= 1:
                     max_seqlen_qo = draft_num
                     (
                         work_metadata,
@@ -1532,6 +1670,8 @@ class AiterAttnBackend(AttentionBackend):
                     reduce_partial_map=reduce_partial_map,
                     num_kv_splits=num_kv_splits,
                     run_graph=False,
+                    local_kv_lens=local_kv_lens,
+                    verify_token_table=verify_token_table,
                 )
             else:
                 draft_num = forward_batch.input_ids.shape[0] // bs
@@ -1712,6 +1852,132 @@ class AiterAttnBackend(AttentionBackend):
                     swa_out_cache_loc=swa_out_cache_loc,
                 )
 
+    def _plan_dcp_decode_metadata(
+        self,
+        kv_indptr: torch.Tensor,
+        kv_indices: torch.Tensor,
+        kv_lens_gpu: torch.Tensor,
+        seq_lens_cpu: Optional[torch.Tensor],
+        bs: int,
+        static_local_kv_lens_cpu: Optional[torch.Tensor] = None,
+    ):
+        """Localize kv_indptr / kv_indices to this rank's DCP shard, in place."""
+        if static_local_kv_lens_cpu is not None:
+            # The planner reads `kv_len_arr_cpu` only for (max, sum), never for
+            # the lengths it writes back, so a static upper bound yields the same
+            # metadata without the GPU->CPU sync.
+            total_local_len = plan_dcp_decode_metadata(
+                kv_lens_gpu,
+                kv_indptr,
+                kv_indices,
+                init_metadata_replay=True,
+                fast_decode_kwargs={"kv_len_arr_cpu": static_local_kv_lens_cpu},
+                bs=bs,
+            )
+        elif seq_lens_cpu is not None:
+            kv_len_arr_cpu = seq_lens_cpu[:bs].to(torch.int32).clone()
+            update_local_kv_lens_for_dcp(kv_len_arr_cpu)
+            total_local_len = plan_dcp_decode_metadata(
+                kv_lens_gpu,
+                kv_indptr,
+                kv_indices,
+                init_metadata_replay=True,
+                fast_decode_kwargs={"kv_len_arr_cpu": kv_len_arr_cpu},
+                bs=bs,
+            )
+        else:
+            total_local_len = plan_dcp_decode_metadata(
+                kv_lens_gpu,
+                kv_indptr,
+                kv_indices,
+                init_metadata_replay=False,
+                fast_decode_kwargs={},
+                bs=bs,
+            )
+
+        # The planner leaves the compacted ids WIDENED (see its docstring), and
+        # mla_gluon indexes the pool directly, so collapse them once per forward
+        # -- the same contract flashinfer_mla_backend.py follows.
+        translator = self.kv_index_translator
+        if total_local_len > 0 and translator.needs_read_translate:
+            valid = kv_indices[:total_local_len]
+            valid.copy_(translator.translate_dcp_read_ids(valid))
+
+    def _build_dcp_local_kv_lens(
+        self,
+        kv_indptr: torch.Tensor,
+        bs: int,
+        out_lens: Optional[torch.Tensor] = None,
+    ):
+        """This rank's shard length per request, in TOKENS (mla_gluon's
+        ``cache_seqlens``). ``kv_indptr`` must already be localized.
+        """
+        lens = (kv_indptr[1 : bs + 1] - kv_indptr[:bs]).to(torch.int32)
+        if out_lens is None:
+            return lens
+        out_lens.copy_(lens)
+        return out_lens
+
+    def _build_dcp_verify_token_table(
+        self,
+        kv_indptr: torch.Tensor,
+        req_pool_indices: torch.Tensor,
+        bs: int,
+        q_len: int,
+        max_local_kv_len: int,
+        out: Optional[torch.Tensor] = None,
+        out_lens: Optional[torch.Tensor] = None,
+    ):
+        """Token table + shard lengths for the prefix attention of DCP verify.
+
+        One row per query token, one column per TOKEN (mla_gluon fixes
+        PAGE_SIZE at 1). Rows of a request repeat that request's shard.
+        """
+        local_kv_lens = self._build_dcp_local_kv_lens(kv_indptr, bs)
+        n_rows = bs * q_len
+        if out is None:
+            # The row stride below is a Triton constexpr, so quantize the eager
+            # width: every distinct value costs a JIT specialization.
+            out = local_kv_lens.new_empty(
+                (
+                    n_rows,
+                    triton.cdiv(max_local_kv_len, _DCP_VERIFY_TABLE_COLS_PER_BLOCK)
+                    * _DCP_VERIFY_TABLE_COLS_PER_BLOCK,
+                )
+            )
+        num_cols = out.shape[1]
+
+        # Write each request's row 0 in place: the row stride handed to the
+        # kernel spans that request's whole block of q_len rows.
+        translator = self.kv_index_translator
+        v2p = translator.full_v2p_table
+        create_mla_kv_page_table_for_dcp[
+            (bs, triton.cdiv(num_cols, _DCP_VERIFY_TABLE_COLS_PER_BLOCK))
+        ](
+            self.req_to_token,
+            req_pool_indices,
+            local_kv_lens,
+            out,
+            v2p,
+            self.req_to_token.stride(0),
+            q_len * num_cols,
+            translator.full_page_multiplier,
+            PHYSICAL_PAGE_SIZE=1,
+            DCP_SIZE=self.dcp_world_size,
+            DCP_RANK=get_parallel().attn_dcp_rank,
+            PAGES_PER_BLOCK=_DCP_VERIFY_TABLE_COLS_PER_BLOCK,
+            HAS_V2P=v2p is not None,
+        )
+        rows = out.view(bs, q_len, num_cols)
+        if q_len > 1:
+            # Source is row 0, destination rows 1.., so the copy never overlaps.
+            rows[:, 1:, :].copy_(rows[:, :1, :].expand(bs, q_len - 1, num_cols))
+
+        if out_lens is None:
+            out_lens = local_kv_lens.new_empty((n_rows,))
+        out_lens.view(bs, q_len).copy_(local_kv_lens.unsqueeze(1).expand(bs, q_len))
+        return out, out_lens
+
     def init_cuda_graph_state(
         self,
         max_bs: int,
@@ -1739,6 +2005,29 @@ class AiterAttnBackend(AttentionBackend):
         self.cuda_graph_kv_last_page_len = torch.ones(
             max_bs, dtype=torch.int32, device=self.device
         )
+        if self.use_mla and self.dcp_world_size > 1:
+            if self.num_draft_tokens:
+                # Target-verify flattens the window into single-token rows, so it
+                # needs max_bs * num_draft_tokens.
+                n_verify_rows = max_bs * self.num_draft_tokens
+                self.cuda_graph_verify_local_kv_lens = torch.zeros(
+                    (n_verify_rows,), dtype=torch.int32, device=self.device
+                )
+                # Capture-stable token table, filled out-of-graph. One column per
+                # TOKEN, so the width is the worst-case shard ceil(ctx_len / W).
+                self.cuda_graph_verify_token_table = torch.zeros(
+                    (n_verify_rows, self._get_dcp_graph_max_local_kv_len()),
+                    dtype=torch.int32,
+                    device=self.device,
+                )
+                # Static per-rank shard bound, one entry per request. Sizes the
+                # verify plan without a sync; see _plan_dcp_decode_metadata.
+                self.cuda_graph_dcp_static_local_kv_lens = torch.full(
+                    (max_bs,),
+                    self._get_dcp_graph_max_local_kv_len(),
+                    dtype=torch.int32,
+                    device="cpu",
+                )
         if kv_indices_buf is None:
             max_num_blocks_per_seq = (
                 self.max_context_len + self.page_size - 1
@@ -1854,6 +2143,10 @@ class AiterAttnBackend(AttentionBackend):
         reduce_final_map = None
         reduce_partial_map = None
 
+        # DCP metadata which will be populated for MLA decode when dcp enabled
+        local_kv_lens = None
+        verify_token_table = None
+
         swa_page_table = None
         max_kv_len = (
             seq_lens_cpu.max().item()
@@ -1887,6 +2180,20 @@ class AiterAttnBackend(AttentionBackend):
                         kv_indices,
                         self.req_to_token.stride(0),
                     )
+
+                    if (
+                        self.use_mla
+                        and self.dcp_world_size > 1
+                        and not forward_mode.is_idle()
+                    ):
+                        kv_lens = seq_lens[:bs].to(torch.int32).clone()
+                        self._plan_dcp_decode_metadata(
+                            kv_indptr,
+                            kv_indices,
+                            kv_lens,
+                            seq_lens_cpu,
+                            bs,
+                        )
                 else:
                     max_q_len = 1
                     kv_indices = self.cuda_graph_page_table
@@ -1946,7 +2253,9 @@ class AiterAttnBackend(AttentionBackend):
                 kv_last_page_len = self.cuda_graph_kv_last_page_len[:bs]
                 max_q_len = 1
 
-                if _use_mla_ps_kernel:
+                # DCP decode builds its own block-table metadata in
+                # forward_decode, so the persist metadata is unused here.
+                if _use_mla_ps_kernel and self.dcp_world_size <= 1:
                     num_kv_splits = self.max_split_per_batch
 
                     self.make_mla_meta_data(
@@ -2008,7 +2317,11 @@ class AiterAttnBackend(AttentionBackend):
                 device=self.device,
             )
             if self.use_mla:
-                kv_lens = seq_lens + self.num_draft_tokens
+                kv_lens = (
+                    seq_lens
+                    if self.dcp_world_size > 1
+                    else seq_lens + self.num_draft_tokens
+                )
             else:
                 kv_lens = seq_lens
             kv_indptr = self.kv_indptr[: bs + 1]
@@ -2039,9 +2352,34 @@ class AiterAttnBackend(AttentionBackend):
             )
             kv_last_page_len = self.cuda_graph_kv_last_page_len[:bs]
 
+            if self.use_mla and self.dcp_world_size > 1:
+                self._plan_dcp_decode_metadata(
+                    kv_indptr,
+                    kv_indices,
+                    seq_lens[:bs].to(torch.int32).clone(),
+                    None,
+                    bs,
+                    static_local_kv_lens_cpu=self.cuda_graph_dcp_static_local_kv_lens[
+                        :bs
+                    ],
+                )
+                n_rows = bs * self.num_draft_tokens
+                (
+                    verify_token_table,
+                    local_kv_lens,
+                ) = self._build_dcp_verify_token_table(
+                    kv_indptr,
+                    req_pool_indices,
+                    bs,
+                    self.num_draft_tokens,
+                    self._get_dcp_graph_max_local_kv_len(),
+                    out=self.cuda_graph_verify_token_table[:n_rows],
+                    out_lens=self.cuda_graph_verify_local_kv_lens[:n_rows],
+                )
+
             if self.use_mla:
                 max_q_len = self.num_draft_tokens
-                if _use_mla_ps_kernel:
+                if _use_mla_ps_kernel and self.dcp_world_size <= 1:
                     num_kv_splits = self.max_split_per_batch
 
                     self.make_mla_meta_data(
@@ -2082,6 +2420,8 @@ class AiterAttnBackend(AttentionBackend):
                     reduce_final_map=reduce_final_map,
                     reduce_partial_map=reduce_partial_map,
                     num_kv_splits=num_kv_splits,
+                    local_kv_lens=local_kv_lens,
+                    verify_token_table=verify_token_table,
                 )
             else:
                 max_q_len = verify_tokens_per_req
@@ -2419,7 +2759,16 @@ class AiterAttnBackend(AttentionBackend):
                         v_scale=v_descale,
                     )
                 elif self.use_mla:
-                    self.token_to_kv_pool.set_kv_buffer(layer, cache_loc, k, v)
+                    if self.dcp_world_size > 1:
+                        kv_lora_rank = v.shape[-1]
+                        self.token_to_kv_pool.set_mla_kv_buffer(
+                            layer,
+                            cache_loc,
+                            k[..., :kv_lora_rank],
+                            k[..., kv_lora_rank:],
+                        )
+                    else:
+                        self.token_to_kv_pool.set_kv_buffer(layer, cache_loc, k, v)
                 elif self._use_fused_fp8_kv_write(layer):
                     # FP8: fuse bf16->fp8 cast + paged write in one kernel.
                     k_cache, v_cache = self.token_to_kv_pool.get_kv_buffer(
@@ -2458,6 +2807,15 @@ class AiterAttnBackend(AttentionBackend):
             V_Buffer = self.token_to_kv_pool.get_value_buffer(layer.layer_id)
             kv_lora_rank = V_Buffer.shape[-1]
             qk_rope_head_dim = K_Buffer.shape[-1] - kv_lora_rank
+
+            if (
+                forward_batch.forward_mode.is_target_verify()
+                and self.dcp_world_size > 1
+            ):
+                # two-stage dcp verify, dispatched before the dims below: the
+                # model provides the per rank kvcache slices.
+                return self._forward_verify_dcp(q, k, layer, k_descale)
+
             qk_nope_head_dim = k.shape[-1] - qk_rope_head_dim
             assert len(q.shape) == 3
             assert len(k.shape) == 3
@@ -2471,6 +2829,20 @@ class AiterAttnBackend(AttentionBackend):
                 extend_no_prefix = not any(forward_batch.extend_prefix_lens_cpu)
                 if forward_batch.mha_return_lse:
                     return self._forward_extend_skip_prefix(q, k, v, layer)
+                if self.dcp_world_size > 1:
+                    if self.use_fp8_prefill_attn and self.head_pad_mode != "zero":
+                        return self.mla_fp8_prefill_attn(q, k, v, layer)
+                    return flash_attn_varlen_func(
+                        q,
+                        k,
+                        v,
+                        qo_indptr,
+                        forward_batch.attn_dcp_metadata.dcp_kv_indptr,
+                        max_q_len,
+                        max_kv_len,
+                        softmax_scale=layer.scaling,
+                        causal=True,
+                    )
                 if kv_indices.shape[0] == 0 or extend_no_prefix:
                     if self.use_fp8_prefill_attn and self.head_pad_mode != "zero":
                         output = self.mla_fp8_prefill_attn(
@@ -3253,6 +3625,10 @@ class AiterAttnBackend(AttentionBackend):
                 )
 
         if self.use_mla:
+            if self.dcp_world_size > 1 and not forward_batch.forward_mode.is_idle():
+                k_buffer = self.token_to_kv_pool.get_key_buffer(layer.layer_id)
+                return self._forward_decode_dcp(q, k_buffer, layer, k_descale)
+
             o = self._forward_mla_decode(q, layer, forward_batch, k_descale)
             return o.reshape(-1, layer.tp_q_head_num * layer.v_head_dim)
         else:

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

@@ -14,7 +14,7 @@ from __future__ import annotations
 import functools
 import inspect
 import logging
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 import torch
 
@@ -82,9 +82,12 @@ def mla_gluon_decode(
     min_kv_seq_len: int,
     kv_scale: float = 1.0,
     qlen: int = 1,
-) -> Optional[torch.Tensor]:
+    use_2d_view: bool = False,
+    return_lse: bool = False,
+):
     """Run Gluon MLA decode for fused Q [num_tokens, H, 576] and MLA KV pool.
-    Returns [num_tokens, H, v_head_dim], or None when Gluon is unavailable.
+    Returns [num_tokens, H, v_head_dim] (or ``(out, lse)`` when ``return_lse``),
+    or None when Gluon is unavailable.
     """
     mla_gluon = _gluon_fn()
     if mla_gluon is None:
@@ -105,7 +108,11 @@ def mla_gluon_decode(
     else:
         o = q.new_empty((batch_size, num_head, kv_lora_rank))
 
-    mla_gluon(
+    extra_kwargs = {}
+    if return_lse:
+        extra_kwargs["return_lse"] = True
+
+    result = mla_gluon(
         q_nope,
         q_pe,
         k_buffer.view(-1, layer.qk_head_dim),
@@ -115,9 +122,15 @@ def mla_gluon_decode(
         sm_scale,
         k_pe=None,
         kv_pe_offset=kv_lora_rank,
-        use_2d_view=False,
+        use_2d_view=use_2d_view,
         kv_scale=kv_scale,
         min_kv_seq_len=min_kv_seq_len,
+        **extra_kwargs,
     )
     # Hand back the caller's flat [num_tokens, H, v] layout either way.
-    return o.flatten(0, 1) if qlen > 1 else o
+    out = o.flatten(0, 1) if qlen > 1 else o
+    if not return_lse:
+        return out
+    # mla_gluon writes the output into `o` and returns it alongside the lse.
+    _, lse = result
+    return out, lse

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

@@ -52,11 +52,13 @@ from sglang.srt.utils import (
     is_cuda,
     is_gfx95_supported,
     is_gfx942_supported,
+    is_hip,
     is_xpu,
     next_power_of_2,
 )
 
 _is_cuda = is_cuda()
+_is_hip = is_hip()
 _is_gfx942 = is_gfx942_supported()
 _is_xpu = is_xpu()
 
@@ -229,8 +231,19 @@ class TritonAttnBackend(AttentionBackend):
             self.use_mla,
             self.use_verify_splitkv,
         )
-        self.dcp_size = get_parallel().attn_dcp_size
-        self.dcp_rank = get_parallel().attn_dcp_rank
+        # TODO: this logic should be fixed in non-hip platform
+        self.is_hip_dspark_draft = (
+            _is_hip
+            and model_runner.is_draft_worker
+            and model_runner.spec_algorithm.is_dspark()
+        )
+        if self.is_hip_dspark_draft:
+            # Drafts never join the dcp group so we ignore it
+            self.dcp_size = 1
+            self.dcp_rank = 0
+        else:
+            self.dcp_size = get_parallel().attn_dcp_size
+            self.dcp_rank = get_parallel().attn_dcp_rank
         self.num_head = (
             model_runner.model_config.get_max_num_attention_heads()
             // get_parallel().attn_tp_size

python/sglang/srt/layers/dcp/comm.py

@@ -37,8 +37,11 @@ from sglang.srt.distributed.device_communicators.pynccl_allocator import (
 )
 from sglang.srt.distributed.parallel_state import GroupCoordinator
 from sglang.srt.runtime_context import get_parallel, get_platform
+from sglang.srt.utils import is_hip
 from sglang.srt.utils.common import is_mnnvl_fabric_device
 
+_is_hip = is_hip()
+
 
 def _warn_deprecated_dcp_accessor(name: str, replacement: str) -> None:
     warnings.warn(
@@ -276,19 +279,21 @@ def all_gather_kv_cache_for_mla_extend(
     k_nope,
     k_pe,
 ):
-    cache_k_nope, cache_k_rope = token_to_kv_pool.get_mla_kv_buffer(
-        attn_mqa,
-        dcp_local_prefix_kv_indices,
-    )
-    extend_prefix_lens_cpu = torch.tensor(extend_prefix_lens_cpu)
-    # all gather kv cache into forward_batch.attn_dcp_metadata.dcp_kv_buffer
-    gathered_kv = all_gather_kv_cache_for_dcp(
-        cache_k_nope,
-        cache_k_rope,
-        extend_prefix_lens_cpu,
-        prefix_starts_cpu=torch.zeros_like(extend_prefix_lens_cpu),
-    )
-    dcp_kv_buffer[:dcp_extend_prefix_lens_sum] = gathered_kv
+    # On hip, skip the all-gather when there is no cached prefix to avoid crash
+    if not _is_hip or dcp_extend_prefix_lens_sum > 0:
+        cache_k_nope, cache_k_rope = token_to_kv_pool.get_mla_kv_buffer(
+            attn_mqa,
+            dcp_local_prefix_kv_indices,
+        )
+        extend_prefix_lens_cpu = torch.tensor(extend_prefix_lens_cpu)
+        # all gather kv cache into forward_batch.attn_dcp_metadata.dcp_kv_buffer
+        gathered_kv = all_gather_kv_cache_for_dcp(
+            cache_k_nope,
+            cache_k_rope,
+            extend_prefix_lens_cpu,
+            prefix_starts_cpu=torch.zeros_like(extend_prefix_lens_cpu),
+        )
+        dcp_kv_buffer[:dcp_extend_prefix_lens_sum] = gathered_kv
 
     # copy local kv cache into forward_batch.attn_dcp_metadata.dcp_kv_buffer
     dcp_kv_buffer[

python/sglang/srt/models/deepseek_common/attention_backend_handler.py

@@ -196,6 +196,8 @@ def handle_attention_aiter(attn, forward_batch):
     if forward_batch.forward_mode.is_extend_without_speculative():
         if not _support_mha_one_shot(attn, forward_batch, "aiter"):
             return AttnForwardMethod.MHA_CHUNKED_KV
+        if get_parallel().dcp_enabled:
+            return AttnForwardMethod.MHA_ONE_SHOT
         return AttnForwardMethod.MHA
     else:
         return AttnForwardMethod.MLA

python/sglang/srt/models/deepseek_common/attention_forward_methods/forward_mha_rocm.py

@@ -14,16 +14,12 @@ import torch
 
 from sglang.kernels.ops.attention.utils import concat_and_cast_mha_k_triton
 from sglang.srt.layers.communicator import get_attn_tp_context
-from sglang.srt.layers.dcp import (
-    all_gather_kv_cache_for_mha_extend,
-    filter_dcp_local_kv_indices,
-)
+from sglang.srt.layers.dcp import all_gather_kv_cache_for_mha_extend
 from sglang.srt.layers.quantization.fp8_utils import (
     materialize_bpreshuffle_fp8_scale_tuple,
 )
 from sglang.srt.model_executor.forward_batch_info import ForwardBatch
 from sglang.srt.model_executor.forward_context import (
-    get_attn_backend,
     get_token_to_kv_pool,
 )
 from sglang.srt.models.deepseek_common.attention_forward_methods.forward_mha import (
@@ -319,11 +315,6 @@ class DeepseekMHARocmForwardMixin:
         forward_batch: ForwardBatch,
     ):
         if _use_aiter_gfx95:
-            kv_indices = filter_dcp_local_kv_indices(kv_indices=kv_indices)
-            # Read door: the pool never translates, so the production site does.
-            kv_indices = get_attn_backend().kv_index_translator.translate_dcp_read_ids(
-                kv_indices
-            )
             kv_a, k_pe = get_token_to_kv_pool().get_mla_kv_buffer(
                 self.attn_mha, kv_indices, dst_dtype
             )

python/sglang/srt/models/deepseek_common/attention_forward_methods/forward_mla.py

@@ -99,7 +99,7 @@ def is_dcp_mla_decode_phase(forward_batch: ForwardBatch) -> bool:
 
 
 def is_mla_dcp_lse_base_on_e(attention_backend: Optional[str]) -> bool:
-    return attention_backend in {"flashmla", "cutedsl_mla"}
+    return attention_backend in {"flashmla", "cutedsl_mla", "aiter"}
 
 
 if _is_cuda:

python/sglang/srt/models/deepseek_common/attention_forward_methods/forward_mla_rocm.py

@@ -591,23 +591,33 @@ class DeepseekMLARocmForwardMixin:
                 q_nope_out = apply_kv_b_lora_q_correction(self, q_nope, q_nope_out)
 
         fuse_rope_for_trtllm_mla = self._fuse_rope_for_trtllm_mla(forward_batch)
-        if (
-            self.rotary_emb is not None
-            and (not fuse_rope_for_trtllm_mla)
-            and (not self._skip_rope_for_dsa_tilelang_fused())
-            and (not self._skip_rope_for_aiter_fused_mla())
+
+        force_rope_for_aiter_dcp_decode = (
+            get_parallel().dcp_enabled
             and (
-                not _use_aiter
-                or not _is_gfx95_supported
-                or self.use_dsa
-                # Non-fused, non-specialized attention backends (e.g. Triton) run
-                # the cat path in forward_absorb_core and need RoPE applied here;
-                # only the aiter fused MLA path and the specialized MLA backends
-                # defer RoPE to their own kernels.
-                or (
-                    self.current_attention_backend
-                    not in FORWARD_ABSORB_CORE_ATTENTION_BACKENDS
-                    and self.current_attention_backend != "aiter"
+                forward_batch.forward_mode.is_decode()
+                or forward_batch.forward_mode.is_target_verify()
+                or forward_batch.forward_mode.is_draft_extend_v2()
+            )
+            and _use_aiter_gfx95
+            and self.current_attention_backend
+            not in FORWARD_ABSORB_CORE_ATTENTION_BACKENDS
+        )
+        if self.rotary_emb is not None and (
+            force_rope_for_aiter_dcp_decode
+            or (
+                (not fuse_rope_for_trtllm_mla)
+                and (not self._skip_rope_for_dsa_tilelang_fused())
+                and (not self._skip_rope_for_aiter_fused_mla())
+                and (
+                    not _use_aiter
+                    or not _is_gfx95_supported
+                    or self.use_dsa
+                    or (
+                        self.current_attention_backend
+                        not in FORWARD_ABSORB_CORE_ATTENTION_BACKENDS
+                        and self.current_attention_backend != "aiter"
+                    )
                 )
             )
         ):
@@ -622,18 +632,23 @@ class DeepseekMLARocmForwardMixin:
                         q_pe=q_pe,
                     )
             elif forward_batch.forward_mode.is_extend():
-                # for extend, gather kv
-                all_gather_kv_cache_for_mla_extend(
-                    get_token_to_kv_pool(),
-                    self.attn_mqa,
-                    forward_batch.extend_prefix_lens_cpu,
-                    forward_batch.attn_dcp_metadata.dcp_local_prefix_kv_indices,
-                    forward_batch.attn_dcp_metadata.dcp_extend_prefix_lens_sum,
-                    forward_batch.attn_dcp_metadata.dcp_kv_buffer,
-                    self.kv_lora_rank,
-                    k_nope,
-                    k_pe,
-                )
+                # Assemble the full sequence into dcp_kv_buffer, which the
+                # backend attends over instead of the sharded local cache.
+                if (
+                    forward_batch.attn_dcp_metadata is not None
+                    and forward_batch.attn_dcp_metadata.dcp_kv_buffer is not None
+                ):
+                    all_gather_kv_cache_for_mla_extend(
+                        get_token_to_kv_pool(),
+                        self.attn_mqa,
+                        forward_batch.extend_prefix_lens_cpu,
+                        forward_batch.attn_dcp_metadata.dcp_local_prefix_kv_indices,
+                        forward_batch.attn_dcp_metadata.dcp_extend_prefix_lens_sum,
+                        forward_batch.attn_dcp_metadata.dcp_kv_buffer,
+                        self.kv_lora_rank,
+                        k_nope,
+                        k_pe,
+                    )
             else:
                 logger.warning(
                     f"not supported forward_mode {forward_batch.forward_mode}"
@@ -763,6 +778,38 @@ class DeepseekMLARocmForwardMixin:
                             else {}
                         ),
                     )
+        elif (
+            _use_aiter
+            and (
+                forward_batch.forward_mode.is_decode()
+                or forward_batch.forward_mode.is_target_verify()
+                or forward_batch.forward_mode.is_draft_extend_v2()
+            )
+            and get_parallel().dcp_enabled
+        ):
+            q = torch.cat([q_nope_out, q_pe], dim=-1)
+            if llama_4_scaling is not None:
+                q[..., : self.kv_lora_rank] *= llama_4_scaling
+            get_token_to_kv_pool().set_mla_kv_buffer(
+                self.attn_mqa,
+                forward_batch.out_cache_loc,
+                k_nope,
+                k_pe,
+            )
+            if forward_batch.forward_mode.is_target_verify():
+                k_window = torch.cat([k_nope, k_pe], dim=-1)
+                v_window = k_nope
+            else:
+                k_window = None
+                v_window = None
+            attn_output, lse = self.attn_mqa_for_dcp_decode(
+                q,
+                k_window,
+                v_window,
+                forward_batch,
+                save_kv_cache=False,
+                **(dict(topk_indices=topk_indices) if topk_indices is not None else {}),
+            )
         else:
             if self._skip_rope_for_aiter_fused_mla():
                 q, _, _, k = _fused_rope_cat_and_cache(