Support CuteDSL mm_fp4 backend (#18801)

python/sglang/srt/layers/quantization/fp4_utils.py

@@ -18,6 +18,7 @@ class Fp4GemmRunnerBackend(Enum):
 
     AUTO = "auto"
     FLASHINFER_CUDNN = "flashinfer_cudnn"
+    FLASHINFER_CUTEDSL = "flashinfer_cutedsl"
     FLASHINFER_CUTLASS = "flashinfer_cutlass"
     FLASHINFER_TRTLLM = "flashinfer_trtllm"
 
@@ -33,6 +34,9 @@ class Fp4GemmRunnerBackend(Enum):
     def is_flashinfer_trtllm(self) -> bool:
         return self == Fp4GemmRunnerBackend.FLASHINFER_TRTLLM
 
+    def is_flashinfer_cutedsl(self) -> bool:
+        return self == Fp4GemmRunnerBackend.FLASHINFER_CUTEDSL
+
     def get_flashinfer_backend(self) -> str:
         """Get the backend string to pass to FlashInfer's mm_fp4 API.
 
@@ -41,7 +45,10 @@ class Fp4GemmRunnerBackend(Enum):
             'flashinfer_trtllm' -> 'trtllm'
             'flashinfer_cutlass' -> 'cutlass'
             'flashinfer_cudnn' -> 'cudnn'
+            'flashinfer_cutedsl' -> 'cute-dsl'
         """
+        if self == Fp4GemmRunnerBackend.FLASHINFER_CUTEDSL:
+            return "cute-dsl"
         if self.value.startswith("flashinfer_"):
             return self.value.removeprefix("flashinfer_")
         else:

python/sglang/srt/server_args.py

@@ -213,6 +213,7 @@ FP8_GEMM_RUNNER_BACKEND_CHOICES = [
 FP4_GEMM_RUNNER_BACKEND_CHOICES = [
     "auto",
     "flashinfer_cudnn",
+    "flashinfer_cutedsl",
     "flashinfer_cutlass",
     "flashinfer_trtllm",
 ]
@@ -4546,7 +4547,8 @@ class ServerArgs:
             "Options: 'auto' (default; selects flashinfer_cudnn on SM120, flashinfer_cutlass otherwise), "
             "'flashinfer_cutlass' (CUTLASS backend), "
             "'flashinfer_cudnn' (FlashInfer cuDNN backend, optimal on CUDA 13+ with cuDNN 9.15+), "
-            "'flashinfer_trtllm' (FlashInfer TensorRT-LLM backend, requires different weight preparation with shuffling). "
+            "'flashinfer_cutedsl' (FlashInfer CuTe DSL backend), "
+            "'flashinfer_trtllm' (FlashInfer TensorRT-LLM backend, requires different weight preparation with shuffling), "
             "NOTE: This replaces the deprecated environment variable "
             "SGLANG_FLASHINFER_FP4_GEMM_BACKEND.",
         )