[fix] /pause_generation and /continue_generation wrong for --tokenizer-worker-num > 1 (#24462)

Co-authored-by: lawrence-harmonic <185285563+lawrence-harmonic@users.noreply.github.com>

python/sglang/srt/managers/io_struct.py

@@ -1381,6 +1381,20 @@ class ContinueGenerationReqInput(BaseReq):
     pass
 
 
+@dataclass
+class TokenizerWorkerRegistration:
+    """Sent by each TokenizerWorker on startup to register its IPC name with the router."""
+
+    worker_ipc_name: str
+
+
+@dataclass
+class PauseContinueBroadcast:
+    """Broadcast from router to all workers to set is_pause state."""
+
+    is_pause: bool
+
+
 @dataclass
 class UpdateWeightFromDiskReqInput(BaseReq):
     # The model path with the new weights

python/sglang/srt/managers/multi_tokenizer_mixin.py

@@ -28,7 +28,7 @@ import sys
 import threading
 from functools import partialmethod
 from multiprocessing import shared_memory
-from typing import TYPE_CHECKING, Any, Dict, Union
+from typing import TYPE_CHECKING, Any, Dict, Optional, Union
 
 import setproctitle
 import zmq
@@ -43,6 +43,10 @@ from sglang.srt.managers.io_struct import (
     BatchEmbeddingOutput,
     BatchStrOutput,
     BatchTokenIDOutput,
+    ContinueGenerationReqInput,
+    PauseContinueBroadcast,
+    PauseGenerationReqInput,
+    TokenizerWorkerRegistration,
 )
 from sglang.srt.managers.tokenizer_manager import TokenizerManager
 from sglang.srt.server_args import PortArgs, ServerArgs
@@ -318,7 +322,12 @@ class MultiHttpWorkerDetokenizerMixin:
 
 
 class MultiTokenizerRouter:
-    """A router to receive requests from TokenizerWorker"""
+    """A router between tokenizer managers and the scheduler/detokenizer manager.
+
+    Forward: tokenizer managers → router → scheduler.
+    Backward: detokenizer manager → router → tokenizer managers.
+    Also broadcasts pause/continue to all tokenizer managers for consistent is_pause state.
+    """
 
     def __init__(
         self,
@@ -342,29 +351,59 @@ class MultiTokenizerRouter:
         self._task = asyncio.run_coroutine_threadsafe(
             self.router_worker_obj(), self._loop
         )
-        # Start handle_loop simultaneously
         self._handle_task = asyncio.run_coroutine_threadsafe(
             print_exception_wrapper(self.handle_loop), self._loop
         )
         self.disaggregation_bootstrap_server = start_disagg_service(self.server_args)
 
+        # Worker IPC names for pause/continue broadcasting
+        self.all_worker_ipcs: set[str] = set()
+        # Shared socket mapping (both coroutines run on self._loop, so safe)
+        self.socket_mapping = SocketMapping()
+
     def _run_loop(self):
         self._loop.run_forever()
 
     async def router_worker_obj(self):
+        """Forward path: workers → scheduler, with pause/continue broadcast."""
         while True:
             recv_obj = await self.receive_from_worker.recv_pyobj()
+
+            if isinstance(recv_obj, TokenizerWorkerRegistration):
+                if recv_obj.worker_ipc_name not in self.all_worker_ipcs:
+                    self.all_worker_ipcs.add(recv_obj.worker_ipc_name)
+                    logger.info(
+                        f"Router registered worker IPC: {recv_obj.worker_ipc_name} "
+                        f"(total: {len(self.all_worker_ipcs)})"
+                    )
+                continue
+
+            if isinstance(
+                recv_obj, (PauseGenerationReqInput, ContinueGenerationReqInput)
+            ):
+                # Broadcast to ALL workers so every worker's is_pause is set
+                is_pause = isinstance(recv_obj, PauseGenerationReqInput)
+                broadcast = PauseContinueBroadcast(is_pause=is_pause)
+                for ipc_name in self.all_worker_ipcs:
+                    self.socket_mapping.send_output(ipc_name, broadcast)
+                # Forward to scheduler rank 0 (it broadcasts to all TP/PP/DP
+                # ranks internally). Skip for abort mode which drains via polling.
+                if not (
+                    isinstance(recv_obj, PauseGenerationReqInput)
+                    and recv_obj.mode == "abort"
+                ):
+                    await self.send_to_scheduler.send_pyobj(recv_obj)
+                continue
+
             await self.send_to_scheduler.send_pyobj(recv_obj)
 
     async def handle_loop(self):
-        # special reqs will recv from scheduler, need to route to right worker
-        self.socket_mapping = SocketMapping()
+        """Backward path: detokenizer → route results to correct worker."""
         while True:
             recv_obj = await self.recv_from_detokenizer.recv_pyobj()
             await self._distribute_result_to_workers(recv_obj)
 
     async def _distribute_result_to_workers(self, recv_obj):
-        # Distribute result to each worker
         if isinstance(recv_obj, BaseReq):
             ipc_names = [recv_obj.http_worker_ipc]
         elif isinstance(recv_obj, BaseBatchReq):
@@ -407,6 +446,63 @@ class TokenizerWorker(TokenizerManager):
             self.send_to_scheduler, 2
         )
 
+        # Register this worker with the router for pause/continue broadcasting
+        reg = TokenizerWorkerRegistration(worker_ipc_name=self.tokenizer_ipc_name)
+        self.send_to_scheduler.send_pyobj(reg)
+
+        # Future for awaiting pause/continue broadcast confirmation
+        self._pause_continue_future: Optional[asyncio.Future] = None
+
+        # Register PauseContinueBroadcast in the result dispatcher so
+        # handle_loop routes it to _handle_pause_continue_broadcast
+        from sglang.utils import TypeBasedDispatcher
+
+        self._result_dispatcher += TypeBasedDispatcher(
+            [(PauseContinueBroadcast, self._handle_pause_continue_broadcast)]
+        )
+
+    async def pause_generation(self, obj: PauseGenerationReqInput):
+        loop = asyncio.get_event_loop()
+        self._pause_continue_future = loop.create_future()
+        # Send to router which will broadcast to all workers
+        # (router also handles forwarding to scheduler for non-abort modes)
+        self.send_to_scheduler.send_pyobj(obj)
+        await self._pause_continue_future
+
+        if obj.mode == "abort":
+            # Abort polling: only the originator checks its own lock state
+            while True:
+                self.abort_request(abort_all=True)
+                is_locked = await self.model_update_lock.is_locked()
+                if not is_locked:
+                    break
+                await asyncio.sleep(1.0)
+
+    async def continue_generation(self, obj: ContinueGenerationReqInput):
+        loop = asyncio.get_event_loop()
+        self._pause_continue_future = loop.create_future()
+        self.send_to_scheduler.send_pyobj(obj)
+        await self._pause_continue_future
+
+    def _handle_pause_continue_broadcast(self, obj: PauseContinueBroadcast):
+        """Called from handle_loop when a broadcast arrives from the router."""
+        loop = asyncio.get_event_loop()
+        loop.create_task(self._apply_pause_continue_broadcast(obj))
+
+    async def _apply_pause_continue_broadcast(self, obj: PauseContinueBroadcast):
+        """Apply pause/continue state under the condition lock."""
+        async with self.is_pause_cond:
+            if obj.is_pause:
+                self.is_pause = True
+            else:
+                self.is_pause = False
+                self.is_pause_cond.notify_all()
+
+        # Resolve the pending future if this worker initiated the pause/continue
+        if self._pause_continue_future and not self._pause_continue_future.done():
+            self._pause_continue_future.set_result(True)
+            self._pause_continue_future = None
+
     def _attach_multi_http_worker_info(self, req: Union[BaseReq, BaseBatchReq]):
 
         if isinstance(req, BaseReq):