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A high-throughput and memory-efficient inference and serving engine for LLMs

Mirrored from https://github.com/tduncan-lum/Nvidia-Optimization-Stack---VLLM.git

Synced Nov 10, 01:30 UTC

Revert "[Attention][MLA] Make `FLASHINFER_MLA` the default MLA backen… (#32484)

Signed-off-by: Matthew Bonanni <mbonanni@redhat.com>

Matthew Bonanni committed Jan 16, 2026 at 23:42 UTC 2e7c89e7084d686014672332f5f32c0aa7b1c6ba
3 files changed +15 -16
vllm/config/attention.py
+1 -1
@@ -35,7 +35,7 @@ class AttentionConfig:
35 use_cudnn_prefill: bool = False
36 """Whether to use cudnn prefill."""
37
38 - use_trtllm_ragged_deepseek_prefill: bool = True
38 + use_trtllm_ragged_deepseek_prefill: bool = False
39 """Whether to use TRTLLM ragged deepseek prefill."""
40
41 use_trtllm_attention: bool | None = None
vllm/model_executor/layers/attention/mla_attention.py
+10 -11
@@ -450,6 +450,7 @@ def use_flashinfer_prefill() -> bool:
450 not vllm_config.attention_config.disable_flashinfer_prefill
451 and flashinfer_available
452 and not vllm_config.attention_config.use_cudnn_prefill
453 + and not vllm_config.attention_config.use_trtllm_ragged_deepseek_prefill
454 and current_platform.is_device_capability_family(100)
455 )
456
@@ -1323,27 +1324,25 @@ class MLACommonImpl(MLACommonBaseImpl[M], Generic[M]):
1324 def __init__(self, *args, **kwargs) -> None:
1325 super().__init__(*args, **kwargs)
1326
1326 - if use_trtllm_ragged_deepseek_prefill():
1327 - logger.info_once(
1328 - "Using TRT-LLM ragged DeepSeek prefill for MLA", scope="local"
1329 - )
1327 + if use_flashinfer_prefill():
1328 + logger.debug_once("Using FlashInfer prefill for MLA")
1329 + self._run_prefill_context_chunk = self._run_prefill_context_chunk_fi
1330 + self._run_prefill_new_tokens = self._run_prefill_new_tokens_fi
1331 + self._pad_v = False
1332 + elif use_trtllm_ragged_deepseek_prefill():
1333 + logger.debug_once("Using TRT-LLM ragged DeepSeek prefill for MLA")
1334 self._run_prefill_context_chunk = (
1335 self._run_prefill_context_chunk_trtllm_ragged
1336 )
1337 self._run_prefill_new_tokens = self._run_prefill_new_tokens_trtllm_ragged
1338 self._pad_v = False
1335 - elif use_flashinfer_prefill():
1336 - logger.info_once("Using FlashInfer prefill for MLA")
1337 - self._run_prefill_context_chunk = self._run_prefill_context_chunk_fi
1338 - self._run_prefill_new_tokens = self._run_prefill_new_tokens_fi
1339 - self._pad_v = False
1339 elif use_cudnn_prefill():
1341 - logger.info_once("Using CUDNN prefill for MLA", scope="local")
1340 + logger.debug_once("Using CUDNN prefill for MLA")
1341 self._run_prefill_context_chunk = self._run_prefill_context_chunk_cudnn
1342 self._run_prefill_new_tokens = self._run_prefill_new_tokens_cudnn
1343 self._pad_v = False
1344 else: # Use FlashAttention
1346 - logger.info_once("Using FlashAttention prefill for MLA", scope="local")
1345 + logger.debug_once("Using FlashAttention prefill for MLA")
1346 self._run_prefill_context_chunk = self._run_prefill_context_chunk_fa
1347 self._run_prefill_new_tokens = self._run_prefill_new_tokens_fa
1348
vllm/platforms/cuda.py
+4 -4
@@ -50,8 +50,8 @@ def _get_backend_priorities(
50 if use_mla:
51 if device_capability.major == 10:
52 return [
53 - AttentionBackendEnum.FLASHINFER_MLA,
53 AttentionBackendEnum.CUTLASS_MLA,
54 + AttentionBackendEnum.FLASHINFER_MLA,
55 AttentionBackendEnum.FLASH_ATTN_MLA,
56 AttentionBackendEnum.FLASHMLA,
57 AttentionBackendEnum.TRITON_MLA,
@@ -183,12 +183,12 @@ class CudaPlatformBase(Platform):
183 if vllm_config.attention_config.backend is None:
184 # Default case
185 if cls.is_device_capability_family(100) and not use_sparse:
186 - # Blackwell => Force FlashInferMLA (unless sparse, i.e. DSv3.2).
187 - use_flashinfer_mla = True
186 + # Blackwell => Force CutlassMLA (unless sparse, i.e. DSv3.2).
187 + use_cutlass_mla = True
188 # Set the backend in AttentionConfig so it's used during
189 # backend selection
190 vllm_config.attention_config.backend = (
191 - AttentionBackendEnum.FLASHINFER_MLA
191 + AttentionBackendEnum.CUTLASS_MLA
192 )
193 else:
194 # Not Blackwell