Improve rate limit accuracy

celery/worker/consumer.py

@@ -182,6 +182,7 @@ class Consumer(object):
         self._restart_state = restart_state(maxR=5, maxT=1)
 
         self._does_info = logger.isEnabledFor(logging.INFO)
+        self._limit_order = 0
         self.on_task_request = on_task_request
         self.on_task_message = set()
         self.amqheartbeat_rate = self.app.conf.BROKER_HEARTBEAT_CHECKRATE
@@ -252,11 +253,17 @@ class Consumer(object):
                 else self.qos.increment_eventually)(
             abs(index) * self.prefetch_multiplier)
 
+    def _limit_move_to_pool(self, request):
+        task_reserved(request)
+        self.on_task_request(request)
+
     def _limit_task(self, request, bucket, tokens):
         if not bucket.can_consume(tokens):
             hold = bucket.expected_time(tokens)
+            pri = self._limit_order = (self._limit_order + 1) % 10
             self.timer.call_after(
-                hold, self._limit_task, (request, bucket, tokens),
+                hold, self._limit_move_to_pool, (request, ),
+                priority=pri,
             )
         else:
             task_reserved(request)