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[Doc] Fix outdated --fp4-gemm-backend documentation (#18350)

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This commit is contained in:
Mohammad Miadh Angkad
2026-02-07 20:42:47 +08:00
committed by GitHub
parent d792aa7618
commit fddef76619
3 changed files with 5 additions and 9 deletions
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2
docs/advanced_features/server_arguments.md
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@@ -267,7 +267,7 @@ Please consult the documentation below and [server_args.py](https://github.com/s
| `--nsa-prefill-backend` | Choose the NSA backend for the prefill stage (overrides `--attention-backend` when running DeepSeek NSA-style attention). | `flashmla_sparse` | `flashmla_sparse`, `flashmla_kv`, `flashmla_auto`, `fa3`, `tilelang`, `aiter` |
| `--nsa-decode-backend` | Choose the NSA backend for the decode stage when running DeepSeek NSA-style attention. Overrides `--attention-backend` for decoding. | `fa3` | `flashmla_sparse`, `flashmla_kv`, `fa3`, `tilelang`, `aiter` |
| `--fp8-gemm-backend` | Choose the runner backend for Blockwise FP8 GEMM operations. Options: 'auto' (default, auto-selects based on hardware), 'deep_gemm' (JIT-compiled; enabled by default on NVIDIA Hopper (SM90) and Blackwell (SM100) when DeepGEMM is installed), 'flashinfer_trtllm' (optimal for Blackwell and low-latency), 'cutlass' (optimal for Hopper/Blackwell GPUs and high-throughput), 'triton' (fallback, widely compatible), 'aiter' (ROCm only). **NOTE**: This replaces the deprecated environment variables SGLANG_ENABLE_FLASHINFER_FP8_GEMM and SGLANG_SUPPORT_CUTLASS_BLOCK_FP8. | `auto` | `auto`, `deep_gemm`, `flashinfer_trtllm`, `cutlass`, `triton`, `aiter` |
| `--fp4-gemm-backend` | Choose the runner backend for NVFP4 GEMM operations. Options: 'auto' (default, auto-selects between flashinfer_cudnn/flashinfer_cutlass based on CUDA/cuDNN version), 'flashinfer_cudnn' (FlashInfer cuDNN backend, optimal on CUDA 13+ with cuDNN 9.15+), 'flashinfer_cutlass' (FlashInfer CUTLASS backend, optimal on CUDA 12), 'flashinfer_trtllm' (FlashInfer TensorRT-LLM backend, requires different weight preparation with shuffling). All backends are from FlashInfer; when FlashInfer is unavailable, sgl-kernel CUTLASS is used as an automatic fallback. **NOTE**: This replaces the deprecated environment variable SGLANG_FLASHINFER_FP4_GEMM_BACKEND. | `auto` | `auto`, `flashinfer_cudnn`, `flashinfer_cutlass`, `flashinfer_trtllm` |
| `--fp4-gemm-backend` | Choose the runner backend for NVFP4 GEMM operations. Options: 'flashinfer_cutlass' (default), 'auto' (auto-selects between flashinfer_cudnn/flashinfer_cutlass based on CUDA/cuDNN version), '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). All backends are from FlashInfer; when FlashInfer is unavailable, sgl-kernel CUTLASS is used as an automatic fallback. **NOTE**: This replaces the deprecated environment variable SGLANG_FLASHINFER_FP4_GEMM_BACKEND. | `flashinfer_cutlass` | `auto`, `flashinfer_cudnn`, `flashinfer_cutlass`, `flashinfer_trtllm` |
| `--disable-flashinfer-autotune` | Flashinfer autotune is enabled by default. Set this flag to disable the autotune. | `False` | bool flag (set to enable) |
## Speculative decoding

6
python/sglang/srt/layers/quantization/modelopt_quant.py
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@@ -133,11 +133,7 @@ def fp4_gemm(
fp4_backend = get_fp4_gemm_runner_backend()
if enable_flashinfer_fp4_gemm:
# Use the remapping logic to convert SGLang backend names to FlashInfer API names
backend = (
fp4_backend.get_flashinfer_backend()
if not fp4_backend.is_auto()
else "cutlass"
)
backend = fp4_backend.get_flashinfer_backend()
return flashinfer_fp4_gemm(
input, weight, input_sf, weight_sf, alpha, out_dtype, backend=backend
)

6
python/sglang/srt/server_args.py
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@@ -448,7 +448,7 @@ class ServerArgs:
grammar_backend: Optional[str] = None
mm_attention_backend: Optional[str] = None
fp8_gemm_runner_backend: str = "auto"
fp4_gemm_runner_backend: str = "auto"
fp4_gemm_runner_backend: str = "flashinfer_cutlass"
nsa_prefill_backend: Optional[str] = (
None # None = auto-detect based on hardware/kv_cache_dtype
)
@@ -3789,9 +3789,9 @@ class ServerArgs:
default=ServerArgs.fp4_gemm_runner_backend,
dest="fp4_gemm_runner_backend",
help="Choose the runner backend for NVFP4 GEMM operations. "
"Options: 'auto' (default, selects between flashinfer_cudnn/flashinfer_cutlass based on CUDA/cuDNN version), "
"Options: 'flashinfer_cutlass' (default), "
"'auto' (auto-selects between flashinfer_cudnn/flashinfer_cutlass based on CUDA/cuDNN version), "
"'flashinfer_cudnn' (FlashInfer cuDNN backend, optimal on CUDA 13+ with cuDNN 9.15+), "
"'flashinfer_cutlass' (FlashInfer CUTLASS backend, optimal on CUDA 12), "
"'flashinfer_trtllm' (FlashInfer TensorRT-LLM backend, requires different weight preparation with shuffling). "
"NOTE: This replaces the deprecated environment variable "
"SGLANG_FLASHINFER_FP4_GEMM_BACKEND.",