diff --git a/doc/eventqueue.md b/doc/eventqueue.md
index cc7abe9..c2b5d82 100644
--- a/doc/eventqueue.md
+++ b/doc/eventqueue.md
@@ -129,7 +129,7 @@ template <typename Predictor>
 bool processIf(Predictor && predictor);
 ```
 Process the event queue. Before processing an event, the event is passed to `predictor` and the event will be processed only if `predictor` returns true.  
-`predictor` is a callable object that takes exactly the same arguments as `EventQueue::enqueue` or have no arguments, and returns a boolean value. eventpp will pass the arguments properly.
+`predictor` is a callable object(function, lambda, etc) that takes exactly the same arguments as `EventQueue::enqueue` or have no arguments, and returns a boolean value. eventpp will pass the arguments properly.
 `processIf` returns true if any event was dispatched, false if no event was dispatched.  
 `processIf` has some good use scenarios:  
 1. Process certain events in certain thread. For example, in a GUI application, the UI related events may be only desired to be processed in the main thread.  
diff --git a/doc/orderedqueuelist.md b/doc/orderedqueuelist.md
index 903ca75..89a1782 100644
--- a/doc/orderedqueuelist.md
+++ b/doc/orderedqueuelist.md
@@ -13,9 +13,12 @@
 <a id="a2_1"></a>
 ## Description
 
-OrderedQueueList is a utility class that sorts the events in an EventQueue in certain order.  
-With OrderedQueueList, we can dispatch events in certain order such as in priority order.  
-This class is used by the QueueList policy. See [document of policies](policies.md) for details.  
+`OrderedQueueList` is a utility class that sorts the events in an EventQueue in certain order.  
+With `OrderedQueueList`, we can dispatch events in certain order such as in priority order.  
+This class is used with the `QueueList` policy. See [document of policies](policies.md) for details and how to implement new `QueueList`.  
+
+Warning: `OrderedQueueList` is not efficient since it simply inherits from `std::list` and sorts the full list on each `splice`.
+To use it in performance critical applications, you should implement your own version with sophisticated algorithm.
 
 <a id="a2_2"></a>
 ## API reference