vllm.v1.engine.llm_engine ¶

class LLMEngine:
    """Legacy LLMEngine for backwards compatibility."""

    def __init__(
        self,
        vllm_config: VllmConfig,
        executor_class: type[Executor],
        log_stats: bool,
        aggregate_engine_logging: bool = False,
        usage_context: UsageContext = UsageContext.ENGINE_CONTEXT,
        stat_loggers: list[StatLoggerFactory] | None = None,
        mm_registry: MultiModalRegistry = MULTIMODAL_REGISTRY,
        use_cached_outputs: bool = False,
        multiprocess_mode: bool = False,
    ) -> None:
        self.vllm_config = vllm_config
        self.observability_config = vllm_config.observability_config
        self.model_config = vllm_config.model_config
        self.cache_config = vllm_config.cache_config

        self.log_stats = log_stats

        parallel_config = vllm_config.parallel_config
        executor_backend = parallel_config.distributed_executor_backend

        self.external_launcher_dp = (
            parallel_config.data_parallel_size > 1
            and executor_backend == "external_launcher"
        )
        # important: init dp group before init the engine_core
        # In the decoupled engine case this is handled in EngineCoreProc.
        if (
            not multiprocess_mode
            and parallel_config.data_parallel_size > 1
            and not self.external_launcher_dp
        ):
            self.dp_group = parallel_config.stateless_init_dp_group()
        else:
            self.dp_group = None
        self.should_execute_dummy_batch = False

        self.input_processor = InputProcessor(self.vllm_config)
        self.io_processor = get_io_processor(
            self.vllm_config,
            self.model_config.io_processor_plugin,
        )

        # OutputProcessor (convert EngineCoreOutputs --> RequestOutput).
        self.output_processor = OutputProcessor(
            self.tokenizer,
            log_stats=self.log_stats,
            stream_interval=self.vllm_config.scheduler_config.stream_interval,
        )
        endpoint = self.observability_config.otlp_traces_endpoint
        if endpoint is not None:
            tracer = init_tracer("vllm.llm_engine", endpoint)
            self.output_processor.tracer = tracer

        # EngineCore (gets EngineCoreRequests and gives EngineCoreOutputs)
        self.engine_core = EngineCoreClient.make_client(
            multiprocess_mode=multiprocess_mode,
            asyncio_mode=False,
            vllm_config=vllm_config,
            executor_class=executor_class,
            log_stats=self.log_stats,
        )

        self.logger_manager: StatLoggerManager | None = None
        if self.log_stats:
            self.logger_manager = StatLoggerManager(
                vllm_config=vllm_config,
                custom_stat_loggers=stat_loggers,
                enable_default_loggers=log_stats,
                aggregate_engine_logging=aggregate_engine_logging,
            )
            self.logger_manager.log_engine_initialized()

        if not multiprocess_mode:
            # for v0 compatibility
            self.model_executor = self.engine_core.engine_core.model_executor  # type: ignore

        if self.external_launcher_dp:
            # If we use DP in external launcher mode, we reuse the
            # existing DP group used for data communication.
            self.dp_group = get_dp_group().cpu_group

        # Don't keep the dummy data in memory
        self.reset_mm_cache()

    @classmethod
    def from_vllm_config(
        cls,
        vllm_config: VllmConfig,
        usage_context: UsageContext = UsageContext.ENGINE_CONTEXT,
        stat_loggers: list[StatLoggerFactory] | None = None,
        disable_log_stats: bool = False,
    ) -> "LLMEngine":
        return cls(
            vllm_config=vllm_config,
            executor_class=Executor.get_class(vllm_config),
            log_stats=(not disable_log_stats),
            usage_context=usage_context,
            stat_loggers=stat_loggers,
            multiprocess_mode=envs.VLLM_ENABLE_V1_MULTIPROCESSING,
        )

    @classmethod
    def from_engine_args(
        cls,
        engine_args: EngineArgs,
        usage_context: UsageContext = UsageContext.ENGINE_CONTEXT,
        stat_loggers: list[StatLoggerFactory] | None = None,
        enable_multiprocessing: bool = False,
    ) -> "LLMEngine":
        """Creates an LLM engine from the engine arguments."""

        # Create the engine configs.
        vllm_config = engine_args.create_engine_config(usage_context)
        executor_class = Executor.get_class(vllm_config)

        if envs.VLLM_ENABLE_V1_MULTIPROCESSING:
            logger.debug("Enabling multiprocessing for LLMEngine.")
            enable_multiprocessing = True

        # Create the LLMEngine.
        return cls(
            vllm_config=vllm_config,
            executor_class=executor_class,
            log_stats=not engine_args.disable_log_stats,
            usage_context=usage_context,
            stat_loggers=stat_loggers,
            multiprocess_mode=enable_multiprocessing,
        )

    def get_num_unfinished_requests(self) -> int:
        return self.output_processor.get_num_unfinished_requests()

    def has_unfinished_requests(self) -> bool:
        has_unfinished = self.output_processor.has_unfinished_requests()
        if self.dp_group is None:
            return has_unfinished or self.engine_core.dp_engines_running()
        return self.has_unfinished_requests_dp(has_unfinished)

    def has_unfinished_requests_dp(self, has_unfinished: bool) -> bool:
        aggregated_has_unfinished = ParallelConfig.has_unfinished_dp(
            self.dp_group, has_unfinished
        )
        if not has_unfinished and aggregated_has_unfinished:
            self.should_execute_dummy_batch = True
        return aggregated_has_unfinished

    @classmethod
    def validate_outputs(cls, outputs, output_type):
        return outputs

    def get_supported_tasks(self) -> tuple[SupportedTask, ...]:
        return self.engine_core.get_supported_tasks()

    def abort_request(self, request_ids: list[str], internal: bool = False) -> None:
        """Remove request_ids from EngineCore and Detokenizer."""

        request_ids = self.output_processor.abort_requests(request_ids, internal)
        self.engine_core.abort_requests(request_ids)

    def add_request(
        self,
        request_id: str,
        prompt: EngineCoreRequest | PromptType,
        params: SamplingParams | PoolingParams,
        arrival_time: float | None = None,
        lora_request: LoRARequest | None = None,
        tokenization_kwargs: dict[str, Any] | None = None,
        trace_headers: Mapping[str, str] | None = None,
        priority: int = 0,
        prompt_text: str | None = None,
    ) -> None:
        # Validate the request_id type.
        if not isinstance(request_id, str):
            raise TypeError(f"request_id must be a string, got {type(request_id)}")

        # Process raw inputs into the request.
        if isinstance(prompt, EngineCoreRequest):
            request = prompt
            if request_id != request.request_id:
                logger.warning_once(
                    "AsyncLLM.add_request() was passed a request_id parameter that "
                    "does not match the EngineCoreRequest.request_id attribute. The "
                    "latter will be used, and the former will be ignored."
                )
        else:
            assert prompt_text is None
            request = self.input_processor.process_inputs(
                request_id,
                prompt,
                params,
                arrival_time,
                lora_request,
                tokenization_kwargs,
                trace_headers,
                priority,
            )
            prompt_text = get_prompt_text(prompt)

        self.input_processor.assign_request_id(request)

        # Use cloned params that may have been updated in process_inputs()
        params = request.params

        n = params.n if isinstance(params, SamplingParams) else 1

        if n == 1:
            # Make a new RequestState and queue.
            self.output_processor.add_request(request, prompt_text, None, 0)
            # Add the request to EngineCore.
            self.engine_core.add_request(request)
            return

        # Fan out child requests (for n>1).
        parent_req = ParentRequest(request)
        for idx in range(n):
            request_id, child_params = parent_req.get_child_info(idx)
            child_request = request if idx == n - 1 else copy(request)
            child_request.request_id = request_id
            child_request.sampling_params = child_params

            # Make a new RequestState and queue.
            self.output_processor.add_request(
                child_request, prompt_text, parent_req, idx
            )
            # Add the request to EngineCore.
            self.engine_core.add_request(child_request)

    def step(self) -> list[RequestOutput | PoolingRequestOutput]:
        if self.should_execute_dummy_batch:
            self.should_execute_dummy_batch = False
            self.engine_core.execute_dummy_batch()
            return []

        # 1) Get EngineCoreOutput from the EngineCore.
        with record_function_or_nullcontext("llm_engine step: get_output"):
            outputs = self.engine_core.get_output()

        # 2) Process EngineCoreOutputs.
        with record_function_or_nullcontext("llm_engine step: process_outputs"):
            iteration_stats = IterationStats() if self.log_stats else None
            processed_outputs = self.output_processor.process_outputs(
                outputs.outputs,
                engine_core_timestamp=outputs.timestamp,
                iteration_stats=iteration_stats,
            )
            self.output_processor.update_scheduler_stats(outputs.scheduler_stats)

        # 3) Abort any reqs that finished due to stop strings.
        with record_function_or_nullcontext("llm_engine step: abort_requests"):
            self.engine_core.abort_requests(processed_outputs.reqs_to_abort)

        # 4) Record stats
        with record_function_or_nullcontext("llm_engine step: record_stats"):
            if self.logger_manager is not None and outputs.scheduler_stats is not None:
                self.logger_manager.record(
                    scheduler_stats=outputs.scheduler_stats,
                    iteration_stats=iteration_stats,
                    mm_cache_stats=self.input_processor.stat_mm_cache(),
                )
                self.do_log_stats_with_interval()

        return processed_outputs.request_outputs

    def start_profile(self):
        self.engine_core.profile(True)

    def stop_profile(self):
        self.engine_core.profile(False)

    def reset_mm_cache(self):
        self.input_processor.clear_mm_cache()
        self.engine_core.reset_mm_cache()

    def reset_prefix_cache(
        self, reset_running_requests: bool = False, reset_connector: bool = False
    ) -> bool:
        return self.engine_core.reset_prefix_cache(
            reset_running_requests, reset_connector
        )

    def reset_encoder_cache(self) -> None:
        """Reset the encoder cache to invalidate all cached encoder outputs.

        This should be called when model weights are updated to ensure
        stale vision embeddings computed with old weights are not reused.
        """
        self.engine_core.reset_encoder_cache()

    def sleep(self, level: int = 1):
        self.engine_core.sleep(level)

        if self.logger_manager is not None:
            self.logger_manager.record_sleep_state(1, level)

    def wake_up(self, tags: list[str] | None = None):
        self.engine_core.wake_up(tags)

        if self.logger_manager is not None:
            self.logger_manager.record_sleep_state(0, 0)

    def is_sleeping(self) -> bool:
        return self.engine_core.is_sleeping()

    def get_metrics(self) -> list[Metric]:
        assert self.log_stats, "Stat logging disabled"
        return get_metrics_snapshot()

    @property
    def tokenizer(self) -> TokenizerLike | None:
        return self.input_processor.tokenizer

    def get_tokenizer(self) -> TokenizerLike:
        return self.input_processor.get_tokenizer()

    @property
    def renderer(self) -> BaseRenderer:
        return self.input_processor.renderer

    def do_log_stats(self) -> None:
        """Log stats if logging is enabled."""
        if self.logger_manager:
            self.logger_manager.log()

    def do_log_stats_with_interval(self) -> None:
        """Log stats when the time interval has passed."""
        now = time.time()
        if not hasattr(self, "_last_log_time"):
            self._last_log_time = now
        if now - self._last_log_time >= envs.VLLM_LOG_STATS_INTERVAL:
            self.do_log_stats()
            self._last_log_time = now

    def add_lora(self, lora_request: LoRARequest) -> bool:
        """Load a new LoRA adapter into the engine for future requests."""
        return self.engine_core.add_lora(lora_request)

    def remove_lora(self, lora_id: int) -> bool:
        """Remove an already loaded LoRA adapter."""
        return self.engine_core.remove_lora(lora_id)

    def list_loras(self) -> set[int]:
        """List all registered adapters."""
        return self.engine_core.list_loras()

    def pin_lora(self, lora_id: int) -> bool:
        """Prevent an adapter from being evicted."""
        return self.engine_core.pin_lora(lora_id)

    def collective_rpc(
        self,
        method: str | Callable[[WorkerBase], _R],
        timeout: float | None = None,
        args: tuple = (),
        kwargs: dict[str, Any] | None = None,
    ) -> list[_R]:
        return self.engine_core.collective_rpc(method, timeout, args, kwargs)

    def apply_model(self, func: Callable[[nn.Module], _R]) -> list[_R]:
        return self.collective_rpc("apply_model", args=(func,))

    def __del__(self):
        dp_group = getattr(self, "dp_group", None)
        if dp_group is not None and not self.external_launcher_dp:
            stateless_destroy_torch_distributed_process_group(dp_group)