vllm-project/vllm · error · ValueError

{options} only applicable when profiler is set to 'proton'

Error message

{options} only applicable when profiler is set to 'proton'

What it means

ProfilerConfig raises when any proton_* option (proton_profiler_dir, proton_context, proton_data != 'tree', proton_backend, proton_mode, proton_hook, proton_output_format) is set to a non-default value while profiler is not 'proton'. The validator diffs each option against its default and lists the offending names in the message.

Source

Thrown at vllm/config/profiler.py:207

            )

        proton_profiler_dir = self.proton_profiler_dir
        non_default_proton_options = [
            name
            for name, value, default in (
                ("proton_profiler_dir", proton_profiler_dir, ""),
                ("proton_context", self.proton_context, "shadow"),
                ("proton_data", self.proton_data, "tree"),
                ("proton_backend", self.proton_backend, None),
                ("proton_mode", self.proton_mode, None),
                ("proton_hook", self.proton_hook, None),
                ("proton_output_format", self.proton_output_format, None),
            )
            if value != default
        ]
        if self.profiler != "proton" and non_default_proton_options:
            options = ", ".join(non_default_proton_options)
            raise ValueError(
                f"{options} only applicable when profiler is set to 'proton'"
            )
        if self.profiler == "proton" and not proton_profiler_dir:
            raise ValueError(
                "proton_profiler_dir must be set when profiler is 'proton'"
            )
        if proton_profiler_dir:
            if _is_uri_path(proton_profiler_dir):
                raise ValueError("proton_profiler_dir must be a local directory")
            self.proton_profiler_dir = os.path.abspath(
                os.path.expanduser(proton_profiler_dir)
            )

        if self.profiler == "proton":
            output_format = self.proton_output_format
            if output_format == "chrome_trace" and self.proton_data != "trace":
                raise ValueError("chrome_trace output requires proton_data='trace'")
            if (

View on GitHub (pinned to c794754062)

Solutions

1. Set profiler='proton' alongside the proton options.
2. Or strip the listed proton_* keys from the config when using torch/cuda profiling.
3. Note proton_data='tree' and proton_context='shadow' are defaults and alone do not trigger this.

Example fix

# before
ProfilerConfig(proton_backend='cupti', proton_profiler_dir='/tmp/p')

# after
ProfilerConfig(profiler='proton', proton_backend='cupti', proton_profiler_dir='/tmp/p')

PROTON_DEFAULTS = {"proton_context": "shadow", "proton_data": "tree",
                  "proton_backend": None, "proton_mode": None,
                  "proton_hook": None, "proton_output_format": None}

def non_default_proton_opts(cfg_kwargs: dict) -> list[str]:
    return [k for k, d in PROTON_DEFAULTS.items() if cfg_kwargs.get(k, d) != d]

def validate(cfg_kwargs: dict) -> None:
    opts = non_default_proton_opts(cfg_kwargs)
    if opts and cfg_kwargs.get("profiler") != "proton":
        raise SystemExit(f"{opts} require profiler='proton'")

When it happens

Trigger: Passing e.g. --profiler-config proton_profiler_dir=/tmp/p,proton_backend=cupti while profiler is None or 'torch'. Any one non-default proton option with a different profiler kind triggers it.

Common situations: Shared profiler-config strings reused across profiler kinds; enabling proton knobs from a profiling guide without selecting the proton profiler itself.

Related errors

• proton_profiler_dir must be set when profiler is 'proton'
• proton_profiler_dir must be a local directory
• chrome_trace output requires proton_data='trace'
• {output_format} output requires proton_data='tree'
• Unable to use nsight profiling unless workers run with Ray.

AI-assisted analysis of vllm-project/vllm@c794754062 (2026-08-14). Data as JSON: /api/errors/01f154037def3235. Report an issue: GitHub.