[Misc] Remove a few dead code paths in DSA (#30973)

python/sglang/srt/environ.py

@@ -669,8 +669,6 @@ class Envs:
     SGLANG_ENABLE_PCG_DSV2_DUAL_STREAM = EnvBool(False)
     SGLANG_DSA_TOPK_BROADCAST = EnvBool(False)
     SGLANG_DISABLE_DSA_INDEXER_FUSION = EnvBool(False)
-    SGLANG_USE_FUSED_METADATA_COPY = EnvBool(True)
-    SGLANG_DSA_USE_FUSED_METADATA_GENERATION = EnvBool(True)
 
     # sgl-kernel
     SGLANG_SKIP_SGL_KERNEL_VERSION_CHECK = EnvBool(False)

python/sglang/srt/layers/attention/dsa/dsa_backend_mtp_precompute.py

@@ -11,7 +11,6 @@ from typing import TYPE_CHECKING, Optional
 
 import torch
 
-from sglang.srt.environ import envs
 from sglang.srt.layers.attention.dsa.utils import compute_dsa_seqlens
 from sglang.srt.layers.attention.utils import seqlens_expand_triton
 from sglang.srt.utils import is_cuda, is_hip
@@ -21,9 +20,6 @@ if TYPE_CHECKING:
 
 _is_cuda = is_cuda()
 _is_hip = is_hip()
-_USE_FUSED_METADATA_GENERATION = (
-    envs.SGLANG_DSA_USE_FUSED_METADATA_GENERATION.get() and not _is_hip
-)
 
 
 @dataclass
@@ -125,7 +121,7 @@ class DeepseekSparseAttnBackendMTPPrecomputeMixin:
         """Precompute metadata for normal decode mode."""
         max_len = self.decode_cuda_graph_metadata[bs].page_table_1.shape[1]
 
-        if _USE_FUSED_METADATA_GENERATION and _is_cuda and not _is_hip:
+        if _is_cuda and not _is_hip:
             from sglang.kernels.ops.attention.dsa_metadata import (
                 fused_dsa_decode_metadata,
             )
@@ -244,7 +240,7 @@ class DeepseekSparseAttnBackendMTPPrecomputeMixin:
         max_seqlen_k = self.decode_cuda_graph_metadata[bs].page_table_1.shape[1]
         seqlens_expanded_size = bs * self.speculative_num_draft_tokens
 
-        if _USE_FUSED_METADATA_GENERATION and _is_cuda and not _is_hip:
+        if _is_cuda and not _is_hip:
             from sglang.kernels.ops.attention.dsa_metadata import (
                 fused_dsa_target_verify_metadata,
             )

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

@@ -136,16 +136,6 @@ def _to_2d_context_lens(seqlens_32: torch.Tensor, batch_size: int) -> torch.Tens
     return seqlens_32.contiguous().view(-1, 1)
 
 
-# Reuse this workspace buffer across all DSA backend instances
-
-# Control whether to use fused metadata copy kernel for cuda graph replay (default: enabled)
-# Set SGLANG_USE_FUSED_METADATA_COPY=0 or false to disable
-_USE_FUSED_METADATA_COPY = envs.SGLANG_USE_FUSED_METADATA_COPY.get() and not _is_hip
-_USE_FUSED_METADATA_GENERATION = (
-    envs.SGLANG_DSA_USE_FUSED_METADATA_GENERATION.get() and not _is_hip
-)
-
-
 @dataclass(frozen=True)
 class DSAFlashMLAMetadata:
     """Metadata only needed by FlashMLA"""
@@ -1381,7 +1371,7 @@ class DeepseekSparseAttnBackend(
             # Normal Decode
             max_len = self._graph_page_table_width(metadata)
 
-            if _USE_FUSED_METADATA_GENERATION and is_cuda() and not _is_hip:
+            if is_cuda() and not _is_hip:
                 from sglang.kernels.ops.attention.dsa_metadata import (
                     fused_dsa_decode_metadata,
                 )
@@ -1423,7 +1413,7 @@ class DeepseekSparseAttnBackend(
         elif forward_mode.is_target_verify():
             max_seqlen_k = self._graph_page_table_width(metadata)
 
-            if _USE_FUSED_METADATA_GENERATION and is_cuda() and not _is_hip:
+            if is_cuda() and not _is_hip:
                 from sglang.kernels.ops.attention.dsa_metadata import (
                     fused_dsa_target_verify_metadata,
                 )
@@ -1521,7 +1511,7 @@ class DeepseekSparseAttnBackend(
                 device=self.device,
             )
 
-            if _USE_FUSED_METADATA_GENERATION and is_cuda() and not _is_hip:
+            if is_cuda() and not _is_hip:
                 from sglang.kernels.ops.attention.dsa_metadata import (
                     fused_dsa_draft_extend_metadata,
                 )