diff --git a/src/Debug/DebugLock.py b/src/Debug/DebugLock.py
new file mode 100644
index 00000000..9cf22520
--- /dev/null
+++ b/src/Debug/DebugLock.py
@@ -0,0 +1,24 @@
+import time
+import logging
+
+import gevent.lock
+
+from Debug import Debug
+
+
+class DebugLock:
+    def __init__(self, log_after=0.01, name="Lock"):
+        self.name = name
+        self.log_after = log_after
+        self.lock = gevent.lock.Semaphore(1)
+        self.release = self.lock.release
+
+    def acquire(self, *args, **kwargs):
+        s = time.time()
+        res = self.lock.acquire(*args, **kwargs)
+        time_taken = time.time() - s
+        if time_taken >= self.log_after:
+            logging.debug("%s: Waited %.3fs after called by %s" %
+                (self.name, time_taken, Debug.formatStack())
+            )
+        return res
diff --git a/src/Worker/WorkerManager.py b/src/Worker/WorkerManager.py
index 2a71b88e..9054f283 100644
--- a/src/Worker/WorkerManager.py
+++ b/src/Worker/WorkerManager.py
@@ -9,6 +9,7 @@ from .WorkerTaskManager import WorkerTaskManager
 from Config import config
 from util import helper
 from Plugin import PluginManager
+from Debug.DebugLock import DebugLock
 import util
 
 
@@ -20,7 +21,7 @@ class WorkerManager(object):
         self.workers = {}  # Key: ip:port, Value: Worker.Worker
         self.tasks = WorkerTaskManager()
         self.next_task_id = 1
-        self.lock_add_task = gevent.lock.Semaphore(1)
+        self.lock_add_task = DebugLock()
         # {"id": 1, "evt": evt, "workers_num": 0, "site": self.site, "inner_path": inner_path, "done": False, "optional_hash_id": None,
         # "time_started": None, "time_added": time.time(), "peers": peers, "priority": 0, "failed": peer_ids, "lock": None or gevent.lock.RLock}
         self.started_task_num = 0  # Last added task num