Add a queue with two priority levels. This is a drop in replacement for

the BlockingQueue from OMV, but allows two priorities.

OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs

@@ -110,7 +110,10 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// <summary>Handlers for incoming packets</summary>
         //PacketEventDictionary packetEvents = new PacketEventDictionary();
         /// <summary>Incoming packets that are awaiting handling</summary>
-        private OpenMetaverse.BlockingQueue<IncomingPacket> packetInbox = new OpenMetaverse.BlockingQueue<IncomingPacket>();
+        //private OpenMetaverse.BlockingQueue<IncomingPacket> packetInbox = new OpenMetaverse.BlockingQueue<IncomingPacket>();
+
+        private DoubleQueue<IncomingPacket> packetInbox = new DoubleQueue<IncomingPacket>();
+
         /// <summary></summary>
         //private UDPClientCollection m_clients = new UDPClientCollection();
         /// <summary>Bandwidth throttle for this UDP server</summary>
@@ -919,7 +922,11 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             #endregion Ping Check Handling
 
             // Inbox insertion
-            packetInbox.Enqueue(new IncomingPacket((LLClientView)client, packet));
+            if (packet.Type == PacketType.AgentUpdate ||
+                packet.Type == PacketType.ChatFromViewer)
+                packetInbox.EnqueueHigh(new IncomingPacket((LLClientView)client, packet));
+            else
+                packetInbox.EnqueueLow(new IncomingPacket((LLClientView)client, packet));
         }
 
         #region BinaryStats
@@ -1519,4 +1526,106 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             }
         }
     }
+
+    internal class DoubleQueue<T> where T:class
+    {
+        private Queue<T> m_lowQueue = new Queue<T>();
+        private Queue<T> m_highQueue = new Queue<T>();
+
+        private object m_syncRoot = new object();
+        private Semaphore m_s = new Semaphore(0, 1);
+
+        public DoubleQueue()
+        {
+        }
+
+        public virtual int Count
+        {
+            get { return m_highQueue.Count + m_lowQueue.Count; }
+        }
+
+        public virtual void Enqueue(T data)
+        {
+            Enqueue(m_lowQueue, data);
+        }
+
+        public virtual void EnqueueLow(T data)
+        {
+            Enqueue(m_lowQueue, data);
+        }
+
+        public virtual void EnqueueHigh(T data)
+        {
+            Enqueue(m_highQueue, data);
+        }
+
+        private void Enqueue(Queue<T> q, T data)
+        {
+            lock (m_syncRoot)
+            {
+                m_lowQueue.Enqueue(data);
+                m_s.WaitOne(0);
+                m_s.Release();
+            }
+        }
+
+        public virtual T Dequeue()
+        {
+            return Dequeue(Timeout.Infinite);
+        }
+
+        public virtual T Dequeue(int tmo)
+        {
+            return Dequeue(TimeSpan.FromMilliseconds(tmo));
+        }
+
+        public virtual T Dequeue(TimeSpan wait)
+        {
+            T res = null;
+
+            if (!Dequeue(wait, ref res))
+                return null;
+
+            return res;
+        }
+
+        public bool Dequeue(int timeout, ref T res)
+        {
+            return Dequeue(TimeSpan.FromMilliseconds(timeout), ref res);
+        }
+
+        public bool Dequeue(TimeSpan wait, ref T res)
+        {
+            if (!m_s.WaitOne(wait))
+                return false;
+            
+            lock (m_syncRoot)
+            {
+                if (m_highQueue.Count > 0)
+                    res = m_highQueue.Dequeue();
+                else
+                    res = m_lowQueue.Dequeue();
+
+                if (m_highQueue.Count == 0 || m_lowQueue.Count == 0)
+                    return true;
+
+                m_s.Release();
+
+                return true;
+            }
+        }
+
+        public virtual void Clear()
+        {
+
+            lock (m_syncRoot)
+            {
+                // Make sure sem count is 0
+                m_s.WaitOne(0);
+
+                m_lowQueue.Clear();
+                m_highQueue.Clear();
+            }
+        }
+    }
 }