Issue #16640: Run less code under a lock in sched module.

Lib/sched.py

@@ -71,8 +71,8 @@ class scheduler:
         """
         if kwargs is _sentinel:
             kwargs = {}
-        with self._lock:
         event = Event(time, priority, action, argument, kwargs)
+        with self._lock:
             heapq.heappush(self._queue, event)
         return event # The ID
 
@@ -82,7 +82,6 @@ class scheduler:
         This is actually the more commonly used interface.
 
         """
-        with self._lock:
         time = self.timefunc() + delay
         return self.enterabs(time, priority, action, argument, kwargs)
 

Misc/NEWS

@@ -200,6 +200,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #16640: Run less code under a lock in sched module.
+
 - Issue #16165: Fix sched.scheduler.run() method was block a scheduler for
   other threads.