vllm.utils ¶

def __dir__() -> list[str]:
    # expose deprecated names in dir() for better UX/tab-completion
    return sorted(list(globals().keys()) + list(_DEPRECATED_MAPPINGS.keys()))

def __getattr__(name: str) -> Any:  # noqa: D401 - short deprecation docstring
    """Module-level getattr to handle deprecated utilities."""
    if name in _DEPRECATED_MAPPINGS:
        submodule_name = _DEPRECATED_MAPPINGS[name]
        warnings.warn(
            f"vllm.utils.{name} is deprecated and will be removed in a future version. "
            f"Use vllm.utils.{submodule_name}.{name} instead.",
            DeprecationWarning,
            stacklevel=2,
        )
        module = __import__(f"vllm.utils.{submodule_name}", fromlist=[submodule_name])
        return getattr(module, name)
    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

def _maybe_force_spawn():
    """Check if we need to force the use of the `spawn` multiprocessing start
    method.
    """
    if os.environ.get("VLLM_WORKER_MULTIPROC_METHOD") == "spawn":
        return

    reasons = []
    if is_in_ray_actor():
        # even if we choose to spawn, we need to pass the ray address
        # to the subprocess so that it knows how to connect to the ray cluster.
        # env vars are inherited by subprocesses, even if we use spawn.
        import ray

        os.environ["RAY_ADDRESS"] = ray.get_runtime_context().gcs_address
        reasons.append("In a Ray actor and can only be spawned")

    from .platform_utils import cuda_is_initialized, xpu_is_initialized

    if cuda_is_initialized():
        reasons.append("CUDA is initialized")
    elif xpu_is_initialized():
        reasons.append("XPU is initialized")

    if reasons:
        logger.warning(
            "We must use the `spawn` multiprocessing start method. "
            "Overriding VLLM_WORKER_MULTIPROC_METHOD to 'spawn'. "
            "See https://docs.vllm.ai/en/latest/usage/"
            "troubleshooting.html#python-multiprocessing "
            "for more information. Reasons: %s",
            "; ".join(reasons),
        )
        os.environ["VLLM_WORKER_MULTIPROC_METHOD"] = "spawn"

def check_use_alibi(model_config: ModelConfig) -> bool:
    cfg = model_config.hf_text_config
    return (
        getattr(cfg, "alibi", False)  # Falcon
        or (
            "BloomForCausalLM" in getattr(model_config.hf_config, "architectures", [])
        )  # Bloom
        or getattr(cfg, "position_encoding_type", "") == "alibi"  # codellm_1b_alibi
        or (
            hasattr(cfg, "attn_config")  # MPT
            and (
                (
                    isinstance(cfg.attn_config, dict)
                    and cfg.attn_config.get("alibi", False)
                )
                or (
                    not isinstance(cfg.attn_config, dict)
                    and getattr(cfg.attn_config, "alibi", False)
                )
            )
        )
    )

def enable_trace_function_call_for_thread(vllm_config: VllmConfig) -> None:
    """Set up function tracing for the current thread,
    if enabled via the VLLM_TRACE_FUNCTION environment variable
    """

    if envs.VLLM_TRACE_FUNCTION:
        tmp_dir = tempfile.gettempdir()
        # add username to tmp_dir to avoid permission issues
        tmp_dir = os.path.join(tmp_dir, getpass.getuser())
        filename = (
            f"VLLM_TRACE_FUNCTION_for_process_{os.getpid()}"
            f"_thread_{threading.get_ident()}_"
            f"at_{datetime.datetime.now()}.log"
        ).replace(" ", "_")
        log_path = os.path.join(
            tmp_dir, "vllm", f"vllm-instance-{vllm_config.instance_id}", filename
        )
        os.makedirs(os.path.dirname(log_path), exist_ok=True)
        enable_trace_function_call(log_path)

def get_mp_context():
    """Get a multiprocessing context with a particular method (spawn or fork).
    By default we follow the value of the VLLM_WORKER_MULTIPROC_METHOD to
    determine the multiprocessing method (default is fork). However, under
    certain conditions, we may enforce spawn and override the value of
    VLLM_WORKER_MULTIPROC_METHOD.
    """
    _maybe_force_spawn()
    mp_method = envs.VLLM_WORKER_MULTIPROC_METHOD
    return multiprocessing.get_context(mp_method)

def import_pynvml():
    """
    Historical comments:

    libnvml.so is the library behind nvidia-smi, and
    pynvml is a Python wrapper around it. We use it to get GPU
    status without initializing CUDA context in the current process.
    Historically, there are two packages that provide pynvml:
    - `nvidia-ml-py` (https://pypi.org/project/nvidia-ml-py/): The official
        wrapper. It is a dependency of vLLM, and is installed when users
        install vLLM. It provides a Python module named `pynvml`.
    - `pynvml` (https://pypi.org/project/pynvml/): An unofficial wrapper.
        Prior to version 12.0, it also provides a Python module `pynvml`,
        and therefore conflicts with the official one. What's worse,
        the module is a Python package, and has higher priority than
        the official one which is a standalone Python file.
        This causes errors when both of them are installed.
        Starting from version 12.0, it migrates to a new module
        named `pynvml_utils` to avoid the conflict.
    It is so confusing that many packages in the community use the
    unofficial one by mistake, and we have to handle this case.
    For example, `nvcr.io/nvidia/pytorch:24.12-py3` uses the unofficial
    one, and it will cause errors, see the issue
    https://github.com/vllm-project/vllm/issues/12847 for example.
    After all the troubles, we decide to copy the official `pynvml`
    module to our codebase, and use it directly.
    """
    import vllm.third_party.pynvml as pynvml

    return pynvml

def init_cached_hf_modules() -> None:
    """
    Lazy initialization of the Hugging Face modules.
    """
    from transformers.dynamic_module_utils import init_hf_modules

    init_hf_modules()

def kill_process_tree(pid: int):
    """
    Kills all descendant processes of the given pid by sending SIGKILL.

    Args:
        pid (int): Process ID of the parent process
    """
    try:
        parent = psutil.Process(pid)
    except psutil.NoSuchProcess:
        return

    # Get all children recursively
    children = parent.children(recursive=True)

    # Send SIGKILL to all children first
    for child in children:
        with contextlib.suppress(ProcessLookupError):
            os.kill(child.pid, signal.SIGKILL)

    # Finally kill the parent
    with contextlib.suppress(ProcessLookupError):
        os.kill(pid, signal.SIGKILL)

def length_from_prompt_token_ids_or_embeds(
    prompt_token_ids: list[int] | None,
    prompt_embeds: torch.Tensor | None,
) -> int:
    """Calculate the request length (in number of tokens) give either
    prompt_token_ids or prompt_embeds.
    """
    prompt_token_len = None if prompt_token_ids is None else len(prompt_token_ids)
    prompt_embeds_len = None if prompt_embeds is None else len(prompt_embeds)

    if prompt_token_len is None:
        if prompt_embeds_len is None:
            raise ValueError("Neither prompt_token_ids nor prompt_embeds were defined.")
        return prompt_embeds_len
    else:
        if prompt_embeds_len is not None and prompt_embeds_len != prompt_token_len:
            raise ValueError(
                "Prompt token ids and prompt embeds had different lengths"
                f" prompt_token_ids={prompt_token_len}"
                f" prompt_embeds={prompt_embeds_len}"
            )
        return prompt_token_len

def random_uuid() -> str:
    return str(uuid.uuid4().hex)

def run_method(
    obj: Any,
    method: str | bytes | Callable,
    args: tuple[Any],
    kwargs: dict[str, Any],
) -> Any:
    """
    Run a method of an object with the given arguments and keyword arguments.
    If the method is string, it will be converted to a method using getattr.
    If the method is serialized bytes and will be deserialized using
    cloudpickle.
    If the method is a callable, it will be called directly.
    """
    if isinstance(method, bytes):
        func = partial(cloudpickle.loads(method), obj)
    elif isinstance(method, str):
        try:
            func = getattr(obj, method)
        except AttributeError:
            raise NotImplementedError(
                f"Method {method!r} is not implemented."
            ) from None
    else:
        func = partial(method, obj)  # type: ignore
    return func(*args, **kwargs)

def set_ulimit(target_soft_limit=65535):
    if sys.platform.startswith("win"):
        logger.info("Windows detected, skipping ulimit adjustment.")
        return

    import resource

    resource_type = resource.RLIMIT_NOFILE
    current_soft, current_hard = resource.getrlimit(resource_type)

    if current_soft < target_soft_limit:
        try:
            resource.setrlimit(resource_type, (target_soft_limit, current_hard))
        except ValueError as e:
            logger.warning(
                "Found ulimit of %s and failed to automatically increase "
                "with error %s. This can cause fd limit errors like "
                "`OSError: [Errno 24] Too many open files`. Consider "
                "increasing with ulimit -n",
                current_soft,
                e,
            )

def warn_for_unimplemented_methods(cls: type[T]) -> type[T]:
    """
    A replacement for `abc.ABC`.
    When we use `abc.ABC`, subclasses will fail to instantiate
    if they do not implement all abstract methods.
    Here, we only require `raise NotImplementedError` in the
    base class, and log a warning if the method is not implemented
    in the subclass.
    """

    original_init = cls.__init__

    def find_unimplemented_methods(self: object):
        unimplemented_methods = []
        for attr_name in dir(self):
            # bypass inner method
            if attr_name.startswith("_"):
                continue

            try:
                attr = getattr(self, attr_name)
                # get the func of callable method
                if callable(attr):
                    attr_func = attr.__func__
            except AttributeError:
                continue
            src = inspect.getsource(attr_func)
            if "NotImplementedError" in src:
                unimplemented_methods.append(attr_name)
        if unimplemented_methods:
            method_names = ",".join(unimplemented_methods)
            msg = f"Methods {method_names} not implemented in {self}"
            logger.debug(msg)

    @wraps(original_init)
    def wrapped_init(self, *args, **kwargs) -> None:
        original_init(self, *args, **kwargs)
        find_unimplemented_methods(self)

    type.__setattr__(cls, "__init__", wrapped_init)
    return cls