[Cherry-Pick] [Feature] support v1 update/clear api for RL (#6761) (#6974)

* [Feature] support v1 update/clear api for RL

* [fix] fix stale control responses when control method timed out

* [chore] remove unused code

* [chore] optimize tags and key_prefix

* [test] fix ci

* [chore] fix code style

* [fix] fix ep control

* [fix] fix ep control for engine cache queue

fastdeploy/inter_communicator/engine_cache_queue.py

@@ -58,6 +58,9 @@ class EngineCacheQueue:
             client_id: Unique identifier for client instances
             local_data_parallel_size: data parallel size
             local_data_parallel_id: local data parallel id
+
+        TODO(liyonghua): Remove multi-DP initialization. Each DP will have its own cache queue.
+
         """
         self.address: Tuple[str, int] = address
         self.authkey: bytes = authkey
@@ -87,6 +90,7 @@ class EngineCacheQueue:
             ]
 
             # Initialize barriers
+            self.barrier = [threading.Barrier(self.num_client) for _ in range(self.local_data_parallel_size)]
             self.barrier0_init = [threading.Barrier(self.num_client) for _ in range(self.local_data_parallel_size)]
             self.barrier1_init = [threading.Barrier(self.num_client) for _ in range(self.local_data_parallel_size)]
             self.barrier2_init = [threading.Barrier(self.num_client) for _ in range(self.local_data_parallel_size)]
@@ -142,6 +146,7 @@ class EngineCacheQueue:
                 callable=lambda idx: self.transfer_task_done_lock_init[idx],
                 proxytype=AcquirerProxy,
             )
+            QueueManager.register("get_barrier", callable=lambda idx: self.barrier[idx])
             QueueManager.register("get_barrier0", callable=lambda idx: self.barrier0_init[idx])
             QueueManager.register("get_barrier1", callable=lambda idx: self.barrier1_init[idx])
             QueueManager.register("get_barrier2", callable=lambda idx: self.barrier2_init[idx])
@@ -191,6 +196,7 @@ class EngineCacheQueue:
             QueueManager.register("get_cache_sync_value")
             QueueManager.register("get_transfer_task_lock")
             QueueManager.register("get_transfer_task_done_lock")
+            QueueManager.register("get_barrier")
             QueueManager.register("get_barrier0")
             QueueManager.register("get_barrier1")
             QueueManager.register("get_barrier2")
@@ -215,6 +221,7 @@ class EngineCacheQueue:
         self.task_done_lock = self.manager.get_transfer_task_done_lock(self.local_data_parallel_id)
 
         # Get barrier proxies
+        self.barrier = self.manager.get_barrier(self.local_data_parallel_id)
         self.barrier0 = self.manager.get_barrier0(self.local_data_parallel_id)
         self.barrier1 = self.manager.get_barrier1(self.local_data_parallel_id)
         self.barrier2 = self.manager.get_barrier2(self.local_data_parallel_id)
@@ -264,7 +271,12 @@ class EngineCacheQueue:
 
     def put_transfer_task(self, item):
         """
-        put swap task
+        Enqueue a cache transfer task (cpu/gpu swap task, read/write storage task)
+        or a control task (cache clearing/restoring).
+
+        The queue is shared by multiple clients. A task can be enqueued only after
+        the previous task has been read by all clients.
+        `task_sync_value` is used as a bitmask to track per-client read status.
         """
         self.task_lock.acquire()
         if 0 < self.task_sync_value.get() < self.total_num:
@@ -279,7 +291,11 @@ class EngineCacheQueue:
 
     def get_transfer_task(self):
         """
-        get swap task
+        Get the current cache transfer task (cpu/gpu swap task, read/write storage task)
+        or control signal (cache clearing/restoring) from cache task queue.
+
+        Each client reads the same task once. The task is removed from the queue
+        only after all clients have read it, tracked by `task_sync_value`.
         """
         data = None
         read_finish = False