3bc94cab69
Signed-off-by: Roger Wang <ywang@roblox.com> Co-authored-by: Michael Goin <michael@neuralmagic.com> Co-authored-by: Roger Wang <ywang@roblox.com>
354 lines
12 KiB
Python
354 lines
12 KiB
Python
import multiprocessing
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import pickle
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import queue
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import threading
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import time
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from contextlib import contextmanager
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from multiprocessing.process import BaseProcess
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from multiprocessing.sharedctypes import Synchronized
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from typing import Any, Iterator, List, Tuple, Type, Union
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import zmq
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import zmq.asyncio
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from msgspec import msgpack
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from vllm.config import CacheConfig, VllmConfig
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from vllm.logger import init_logger
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from vllm.usage.usage_lib import UsageContext
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from vllm.v1.core.scheduler import Scheduler
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from vllm.v1.engine import (EngineCoreOutput, EngineCoreOutputs,
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EngineCoreProfile, EngineCoreRequest,
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EngineCoreRequestType)
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from vllm.v1.engine.mm_input_mapper import MMInputMapper
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from vllm.v1.executor.gpu_executor import GPUExecutor
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from vllm.v1.request import Request, RequestStatus
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from vllm.v1.serial_utils import PickleEncoder
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from vllm.version import __version__ as VLLM_VERSION
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logger = init_logger(__name__)
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POLLING_TIMEOUT_MS = 5000
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POLLING_TIMEOUT_S = POLLING_TIMEOUT_MS // 1000
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LOGGING_TIME_S = 5000
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class EngineCore:
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"""Inner loop of vLLM's Engine."""
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def __init__(
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self,
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vllm_config: VllmConfig,
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executor_class: Type[GPUExecutor],
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usage_context: UsageContext,
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):
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assert vllm_config.model_config.task != "embedding"
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logger.info("Initializing an LLM engine (v%s) with config: %s",
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VLLM_VERSION, vllm_config)
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# Setup Model.
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self.model_executor = executor_class(vllm_config)
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# Setup KV Caches and update CacheConfig after profiling.
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num_gpu_blocks, num_cpu_blocks = self._initialize_kv_caches(
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vllm_config.cache_config)
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vllm_config.cache_config.num_gpu_blocks = num_gpu_blocks
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vllm_config.cache_config.num_cpu_blocks = num_cpu_blocks
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# Set up multimodal input mapper (e.g., convert PIL images to tensors).
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self.mm_input_mapper = MMInputMapper(vllm_config.model_config)
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# Setup scheduler.
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self.scheduler = Scheduler(vllm_config.scheduler_config,
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vllm_config.cache_config,
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vllm_config.lora_config)
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self._last_logging_time = time.time()
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def _initialize_kv_caches(self,
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cache_config: CacheConfig) -> Tuple[int, int]:
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num_gpu_blocks, _ = self.model_executor.determine_num_available_blocks(
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)
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if cache_config.num_gpu_blocks_override is not None:
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num_gpu_blocks_override = cache_config.num_gpu_blocks_override
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logger.info(
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"Overriding num_gpu_blocks=%d with "
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"num_gpu_blocks_override=%d", num_gpu_blocks,
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num_gpu_blocks_override)
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num_gpu_blocks = num_gpu_blocks_override
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num_cpu_blocks = 0
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self.model_executor.initialize_cache(num_gpu_blocks)
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return num_gpu_blocks, num_cpu_blocks
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def add_request(self, request: EngineCoreRequest):
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"""Add request to the scheduler."""
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req = Request.from_engine_core_request(request)
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self.scheduler.add_request(req)
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def abort_requests(self, request_ids: List[str]):
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"""Abort requests from the scheduler."""
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# TODO: The scheduler doesn't really need to know the
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# specific finish reason, TBD whether we propagate that
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# (i.e. client-aborted vs stop criteria met).
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self.scheduler.finish_requests(request_ids,
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RequestStatus.FINISHED_ABORTED)
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def step(self) -> List[EngineCoreOutput]:
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"""Schedule, execute, and make output."""
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if not self.scheduler.has_unfinished_requests():
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return []
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scheduler_output = self.scheduler.schedule()
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output = self.model_executor.execute_model(scheduler_output)
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engine_core_outputs = self.scheduler.update_from_output(
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scheduler_output, output)
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return engine_core_outputs
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def profile(self, is_start=True):
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self.model_executor.worker.profile(is_start)
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class EngineCoreProc(EngineCore):
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"""ZMQ-wrapper for running EngineCore in background process."""
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READY_STR = "READY"
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def __init__(
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self,
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vllm_config: VllmConfig,
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executor_class: Type[GPUExecutor],
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usage_context: UsageContext,
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input_path: str,
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output_path: str,
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ready_path: str,
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should_shutdown: Synchronized,
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):
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super().__init__(vllm_config, executor_class, usage_context)
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# Signal from main process to shutdown (multiprocessing.Value).
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self.should_shutdown = should_shutdown
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# Background Threads and Queues for IO. These enable us to
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# overlap ZMQ socket IO with GPU since they release the GIL,
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# and to overlap some serialization/deserialization with the
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# model forward pass.
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# Threads handle Socket <-> Queues and core_busy_loop uses Queue.
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self.input_queue = queue.Queue()
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self.output_queue = queue.Queue()
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threading.Thread(target=self.process_input_socket,
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args=(input_path, ),
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daemon=True).start()
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threading.Thread(target=self.process_output_socket,
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args=(output_path, ),
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daemon=True).start()
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# Send Readiness signal to EngineClient.
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with self.make_socket(ready_path, zmq.constants.PUSH) as ready_socket:
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ready_socket.send_string(EngineCoreProc.READY_STR)
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@contextmanager
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def make_socket(self, path: str, type: Any) -> Iterator[zmq.Socket]:
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"""Context manager for use """
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ctx = zmq.Context()
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try:
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socket = ctx.socket(type)
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if type == zmq.constants.PULL:
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socket.connect(path)
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elif type == zmq.constants.PUSH:
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socket.bind(path)
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else:
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raise ValueError(f"Unknown Socket Type: {type}")
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yield socket
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except KeyboardInterrupt:
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logger.debug("EngineCore had Keyboard Interrupt.")
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finally:
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ctx.destroy(linger=0)
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@staticmethod
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def wait_for_startup(
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proc: BaseProcess,
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ready_path: str,
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) -> None:
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"""Wait until the EngineCore is ready."""
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try:
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sync_ctx = zmq.Context() # type: ignore[attr-defined]
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socket = sync_ctx.socket(zmq.constants.PULL)
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socket.connect(ready_path)
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# Wait for EngineCore to send EngineCoreProc.READY_STR.
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while socket.poll(timeout=POLLING_TIMEOUT_MS) == 0:
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logger.debug("Waiting for EngineCoreProc to startup.")
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if not proc.is_alive():
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raise RuntimeError("EngineCoreProc failed to start.")
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message = socket.recv_string()
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assert message == EngineCoreProc.READY_STR
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except BaseException as e:
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logger.exception(e)
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raise e
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finally:
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sync_ctx.destroy(linger=0)
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@staticmethod
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def make_engine_core_process(
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vllm_config: VllmConfig,
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executor_class: Type[GPUExecutor],
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usage_context: UsageContext,
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input_path: str,
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output_path: str,
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ready_path: str,
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should_shutdown: Synchronized,
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) -> BaseProcess:
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# The current process might have CUDA context,
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# so we need to spawn a new process.
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# NOTE(rob): this is a problem for using EngineCoreProc w/
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# LLM, since we need a if __name__ == "__main__" guard.
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context = multiprocessing.get_context("spawn")
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process_kwargs = {
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"input_path": input_path,
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"output_path": output_path,
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"ready_path": ready_path,
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"vllm_config": vllm_config,
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"executor_class": executor_class,
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"usage_context": usage_context,
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"should_shutdown": should_shutdown
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}
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# Run EngineCore busy loop in background process.
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proc = context.Process(target=EngineCoreProc.run_engine_core,
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kwargs=process_kwargs)
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proc.start()
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# Wait for startup
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EngineCoreProc.wait_for_startup(proc, ready_path)
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return proc
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@staticmethod
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def run_engine_core(*args, **kwargs):
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"""Launch EngineCore busy loop in background process."""
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try:
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engine_core = EngineCoreProc(*args, **kwargs)
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engine_core.run_busy_loop()
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except KeyboardInterrupt:
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logger.debug("EngineCore interrupted.")
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except BaseException as e:
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logger.exception(e)
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raise e
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def run_busy_loop(self):
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"""Core busy loop of the EngineCore."""
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# Loop until we get a shutdown signal.
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while not self.should_shutdown:
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# 1) Poll the input queue until there is work to do.
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if not self.scheduler.has_unfinished_requests():
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while True:
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try:
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req = self.input_queue.get(timeout=POLLING_TIMEOUT_S)
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self._handle_client_request(req)
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break
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except queue.Empty:
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self._log_stats()
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logger.debug("EngineCore busy loop waiting.")
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if self.should_shutdown:
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return
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# 2) Handle any new client requests (Abort or Add).
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while not self.input_queue.empty():
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req = self.input_queue.get_nowait()
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self._handle_client_request(req)
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# 3) Step the engine core.
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outputs = self.step()
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# 4) Put EngineCoreOutputs into the output queue.
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self.output_queue.put_nowait(outputs)
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self._log_stats()
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def _log_stats(self):
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"""Log basic stats every LOGGING_TIME_S"""
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now = time.time()
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if now - self._last_logging_time > LOGGING_TIME_S:
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logger.info(
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"RUNNING: %s | WAITING: %s",
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len(self.scheduler.running),
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len(self.scheduler.waiting),
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)
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self._last_logging_time = now
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def _handle_client_request(
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self, request: Union[EngineCoreRequest, EngineCoreProfile,
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List[str]]) -> None:
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"""Handle EngineCoreRequest or EngineCoreABORT from Client."""
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if isinstance(request, EngineCoreRequest):
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self.add_request(request)
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elif isinstance(request, EngineCoreProfile):
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self.model_executor.worker.profile(request.is_start)
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else:
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# TODO: make an EngineCoreAbort wrapper
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assert isinstance(request, list)
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self.abort_requests(request)
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def process_input_socket(self, input_path: str):
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"""Input socket IO thread."""
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# Msgpack serialization decoding.
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decoder_add_req = PickleEncoder()
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decoder_abort_req = PickleEncoder()
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with self.make_socket(input_path, zmq.constants.PULL) as socket:
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while True:
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# (RequestType, RequestData)
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type_frame, data_frame = socket.recv_multipart(copy=False)
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request_type = type_frame.buffer
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request_data = data_frame.buffer
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# Deserialize the request data.
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if request_type == EngineCoreRequestType.ADD.value:
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request = decoder_add_req.decode(request_data)
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elif request_type == EngineCoreRequestType.ABORT.value:
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request = decoder_abort_req.decode(request_data)
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elif request_type == EngineCoreRequestType.PROFILE.value:
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request = pickle.loads(request_data)
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else:
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raise ValueError(f"Unknown RequestType: {request_type}")
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# Push to input queue for core busy loop.
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self.input_queue.put_nowait(request)
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def process_output_socket(self, output_path: str):
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"""Output socket IO thread."""
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# Msgpack serialization encoding.
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encoder = msgpack.Encoder()
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# Reuse send buffer.
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buffer = bytearray()
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with self.make_socket(output_path, zmq.constants.PUSH) as socket:
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while True:
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engine_core_outputs = self.output_queue.get()
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outputs = EngineCoreOutputs(outputs=engine_core_outputs)
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encoder.encode_into(outputs, buffer)
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socket.send_multipart((buffer, ), copy=False)
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