vllm.entrypoints.cli.benchmark.mm_processor ¶

class BenchmarkMMProcessorSubcommand(BenchmarkSubcommandBase):
    r"""`vllm bench mm-processor` profiles the multimodal input processor pipeline of
    vision-language models. It measures per-stage latency from the HuggingFace
    processor through to the encoder forward pass, helping you identify
    preprocessing bottlenecks and understand how different image resolutions or
    item counts affect end-to-end request time.

    The benchmark supports two data sources: synthetic random multimodal inputs
    (`random-mm`) and HuggingFace datasets (`hf`). Warmup requests are run before
    measurement to ensure stable results.

    ## Quick Start

    ```bash
    vllm bench mm-processor \
      --model Qwen/Qwen2-VL-7B-Instruct \
      --dataset-name random-mm \
      --num-prompts 50 \
      --random-input-len 300 \
      --random-output-len 40 \
      --random-mm-base-items-per-request 2 \
      --random-mm-limit-mm-per-prompt '{"image": 3, "video": 0}' \
      --random-mm-bucket-config '{(256, 256, 1): 0.7, (720, 1280, 1): 0.3}'
    ```

    ## Measured Stages

    | Stage | Description |
    | ----- | ----------- |
    | `get_mm_hashes_secs` | Time spent hashing multimodal inputs |
    | `get_cache_missing_items_secs` | Time spent looking up the processor cache |
    | `apply_hf_processor_secs` | Time spent in the HuggingFace processor |
    | `merge_mm_kwargs_secs` | Time spent merging multimodal kwargs |
    | `apply_prompt_updates_secs` | Time spent updating prompt tokens |
    | `preprocessor_total_secs` | Total preprocessing time |
    | `encoder_forward_secs` | Time spent in the encoder model forward pass |
    | `num_encoder_calls` | Number of encoder invocations per request |

    The benchmark also reports end-to-end latency (TTFT + decode time) per
    request. Use `--metric-percentiles` to select which percentiles to report
    (default: p99) and `--output-json` to save results.

    For more examples (HF datasets, warmup, JSON output), see the
    [multimodal processor benchmark guide](https://docs.vllm.ai/en/latest/benchmarking/cli/#multimodal-processor-benchmark).
    """

    name = "mm-processor"
    help = "Benchmark multimodal processor latency across different configurations."

    @classmethod
    def add_cli_args(cls, parser: FlexibleArgumentParser) -> None:
        # The class docstring is the page overview / `--help` description.
        if cls.__doc__:
            parser.description = inspect.cleandoc(cls.__doc__)
        add_cli_args(parser)

    @staticmethod
    def cmd(args: argparse.Namespace) -> None:
        main(args)