[V1] Simplify Shutdown (#11659)

tests/v1/engine/test_engine_core_client.py

@@ -142,9 +142,6 @@ def test_engine_core_client(monkeypatch, multiprocessing_mode: bool):
 
         client.abort_requests([request.request_id])
 
-        # Shutdown the client.
-        client.shutdown()
-
 
 @pytest.mark.asyncio
 async def test_engine_core_client_asyncio(monkeypatch):
@@ -200,6 +197,3 @@ async def test_engine_core_client_asyncio(monkeypatch):
             else:
                 assert len(outputs[req_id]) == MAX_TOKENS, (
                     f"{len(outputs[req_id])=}, {MAX_TOKENS=}")
-
-        # Shutdown the client.
-        client.shutdown()

vllm/entrypoints/llm.py

@@ -232,11 +232,6 @@ class LLM:
 
         self.request_counter = Counter()
 
-    def __del__(self):
-        if hasattr(self, 'llm_engine') and self.llm_engine and hasattr(
-                self.llm_engine, "shutdown"):
-            self.llm_engine.shutdown()
-
     @staticmethod
     def get_engine_class() -> Type[LLMEngine]:
         if envs.VLLM_USE_V1:

vllm/v1/engine/async_llm.py

@@ -103,9 +103,6 @@ class AsyncLLM(EngineClient):
 
         self.output_handler: Optional[asyncio.Task] = None
 
-    def __del__(self):
-        self.shutdown()
-
     @classmethod
     def from_engine_args(
         cls,

vllm/v1/engine/core.py

@@ -203,7 +203,6 @@ class EngineCoreProc(EngineCore):
         finally:
             if engine_core is not None:
                 engine_core.shutdown()
-                engine_core = None
 
     def run_busy_loop(self):
         """Core busy loop of the EngineCore."""

vllm/v1/engine/core_client.py

@@ -1,4 +1,6 @@
-from typing import List, Optional, Type
+import weakref
+from abc import ABC, abstractmethod
+from typing import List, Type
 
 import msgspec
 import zmq
@@ -18,7 +20,7 @@ from vllm.v1.utils import BackgroundProcHandle
 logger = init_logger(__name__)
 
 
-class EngineCoreClient:
+class EngineCoreClient(ABC):
     """
     EngineCoreClient: subclasses handle different methods for pushing 
         and pulling from the EngineCore for asyncio / multiprocessing.
@@ -52,8 +54,9 @@ class EngineCoreClient:
 
         return InprocClient(vllm_config, executor_class, log_stats)
 
+    @abstractmethod
     def shutdown(self):
-        pass
+        ...
 
     def get_output(self) -> List[EngineCoreOutput]:
         raise NotImplementedError
@@ -107,9 +110,6 @@ class InprocClient(EngineCoreClient):
     def shutdown(self):
         self.engine_core.shutdown()
 
-    def __del__(self):
-        self.shutdown()
-
     def profile(self, is_start: bool = True) -> None:
         self.engine_core.profile(is_start)
 
@@ -139,10 +139,14 @@ class MPClient(EngineCoreClient):
         self.decoder = msgspec.msgpack.Decoder(EngineCoreOutputs)
 
         # ZMQ setup.
-        if asyncio_mode:
-            self.ctx = zmq.asyncio.Context()
-        else:
-            self.ctx = zmq.Context()  # type: ignore[attr-defined]
+        self.ctx = (
+            zmq.asyncio.Context()  # type: ignore[attr-defined]
+            if asyncio_mode else zmq.Context())  # type: ignore[attr-defined]
+
+        # Note(rob): shutdown function cannot be a bound method,
+        # else the gc cannot collect the object.
+        self._finalizer = weakref.finalize(self, lambda x: x.destroy(linger=0),
+                                           self.ctx)
 
         # Paths and sockets for IPC.
         output_path = get_open_zmq_ipc_path()
@@ -153,7 +157,6 @@ class MPClient(EngineCoreClient):
                                             zmq.constants.PUSH)
 
         # Start EngineCore in background process.
-        self.proc_handle: Optional[BackgroundProcHandle]
         self.proc_handle = BackgroundProcHandle(
             input_path=input_path,
             output_path=output_path,
@@ -166,12 +169,11 @@ class MPClient(EngineCoreClient):
             })
 
     def shutdown(self):
-        # Shut down the zmq context.
-        self.ctx.destroy(linger=0)
-
-        if hasattr(self, "proc_handle") and self.proc_handle:
+        """Clean up background resources."""
+        if hasattr(self, "proc_handle"):
             self.proc_handle.shutdown()
-            self.proc_handle = None
+
+        self._finalizer()
 
 
 class SyncMPClient(MPClient):

vllm/v1/engine/llm_engine.py

@@ -205,10 +205,3 @@ class LLMEngine:
                             f"found type: {type(tokenizer_group)}")
 
         return tokenizer_group
-
-    def __del__(self):
-        self.shutdown()
-
-    def shutdown(self):
-        if engine_core := getattr(self, "engine_core", None):
-            engine_core.shutdown()

vllm/v1/utils.py

@@ -1,3 +1,4 @@
+import multiprocessing
 import os
 import weakref
 from collections.abc import Sequence
@@ -91,8 +92,6 @@ class BackgroundProcHandle:
         target_fn: Callable,
         process_kwargs: Dict[Any, Any],
     ):
-        self._finalizer = weakref.finalize(self, self.shutdown)
-
         context = get_mp_context()
         reader, writer = context.Pipe(duplex=False)
 
@@ -102,11 +101,11 @@ class BackgroundProcHandle:
         process_kwargs["ready_pipe"] = writer
         process_kwargs["input_path"] = input_path
         process_kwargs["output_path"] = output_path
-        self.input_path = input_path
-        self.output_path = output_path
 
-        # Run Detokenizer busy loop in background process.
+        # Run busy loop in background process.
         self.proc = context.Process(target=target_fn, kwargs=process_kwargs)
+        self._finalizer = weakref.finalize(self, shutdown, self.proc,
+                                           input_path, output_path)
         self.proc.start()
 
         # Wait for startup.
@@ -114,21 +113,24 @@ class BackgroundProcHandle:
             raise RuntimeError(f"{process_name} initialization failed. "
                                "See root cause above.")
 
-    def __del__(self):
-        self.shutdown()
-
     def shutdown(self):
-        # Shutdown the process if needed.
-        if hasattr(self, "proc") and self.proc.is_alive():
-            self.proc.terminate()
-            self.proc.join(5)
+        self._finalizer()
 
-            if self.proc.is_alive():
-                kill_process_tree(self.proc.pid)
 
-        # Remove zmq ipc socket files
-        ipc_sockets = [self.output_path, self.input_path]
-        for ipc_socket in ipc_sockets:
-            socket_file = ipc_socket.replace("ipc://", "")
-            if os and os.path.exists(socket_file):
-                os.remove(socket_file)
+# Note(rob): shutdown function cannot be a bound method,
+# else the gc cannot collect the object.
+def shutdown(proc: multiprocessing.Process, input_path: str, output_path: str):
+    # Shutdown the process.
+    if proc.is_alive():
+        proc.terminate()
+        proc.join(5)
+
+        if proc.is_alive():
+            kill_process_tree(proc.pid)
+
+    # Remove zmq ipc socket files.
+    ipc_sockets = [output_path, input_path]
+    for ipc_socket in ipc_sockets:
+        socket_file = ipc_socket.replace("ipc://", "")
+        if os and os.path.exists(socket_file):
+            os.remove(socket_file)