ValueError: moe_backend='flashinfer_b12x' is not supported for FP8 MoE.

#5
by shakhizat - opened

Hello,

When running on an NVIDIA RTX PRO 6000 Blackwell GPU, I encountered the following issue:

ValueError: moe_backend='flashinfer_b12x' is not supported for FP8 MoE. Expected one of ['triton', 'deep_gemm', 'cutlass', 'flashinfer_trtllm', 'flashinfer_cutlass', 'marlin', 'humming', 'aiter', 'hpc'].
[rank0]:[W713 13:28:01.345067028 ProcessGroupNCCL.cpp:1575] Warning: WARNING: destroy_process_group() was not called before program exit, which can leak resources. For more info, please see https://pytorch.org/docs/stable/distributed.html#shutdown (function operator())

on dgx spark the same error

Unsloth AI org

@shakhizat For RTX PRO 6000 - no need for the flag - set "flashinfer_trtllm" or "flashinfer_cutlass"

@moranilt You need the latest vLLM:

uv venv unsloth-nvfp4-env --python 3.13
source unsloth-nvfp4-env/bin/activate
uv pip install "vllm>=0.25.0" "flashinfer-python>=0.6.13" "nvidia-cutlass-dsl>=4.5.2" \
    --torch-backend=auto

export CUTE_DSL_ARCH=sm_121a
vllm serve unsloth/Qwen3.6-35B-A3B-NVFP4 --moe-backend flashinfer_b12x

@danielhanchen tell me what should I add for this docker compose setup. I'm using ifficial vllm image v0.25.0

  qwen-dense:
    image: vllm/vllm-openai:v0.25.0
    container_name: qwen-dense
    deploy:
      resources:
        reservations:
          devices:
            - driver: nvidia
              device_ids: ['0'] 
              capabilities: [gpu]
    environment:
      - HF_TOKEN=token
      - CUTE_DSL_ARCH=sm_121a
      - CUDA_VISIBLE_DEVICES=0
    volumes:
      - ~/.cache/huggingface:/root/.cache/huggingface
    ipc: host
    ports:
      - "8000:8000"
    command: >
      --model unsloth/Qwen3.6-27B-NVFP4
      --port 8000
      --reasoning-parser qwen3
      --dtype auto
      --kv-cache-dtype fp8
      --tensor-parallel-size 1
      --max-num-seqs 8
      --max-model-len 190000
      --gpu-memory-utilization 0.7
      --trust-remote-code
      --enable-prefix-caching
      --enable-prompt-tokens-details
      --max-num-batched-tokens 65536
      --enable-auto-tool-choice
      --tool-call-parser qwen3_coder
      --quantization compressed-tensors
      --attention-backend flashinfer
      --moe-backend flashinfer_b12x
      --enable-chunked-prefill
      --async-scheduling
      --speculative-config '{"method":"mtp","num_speculative_tokens":2}'
      --default-chat-template-kwargs '{"preserve_thinking":false}'

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