changes on lludp acks and resends

5 files changed, 186 insertions, 171 deletions

diff --git a/OpenSim/Region/ClientStack/Linden/Caps/BunchOfCaps/BunchOfCaps.cs b/OpenSim/Region/ClientStack/Linden/Caps/BunchOfCaps/BunchOfCaps.cs
index 316d39d..35e18a0 100644
--- a/OpenSim/Region/ClientStack/Linden/Caps/BunchOfCaps/BunchOfCaps.cs
+++ b/OpenSim/Region/ClientStack/Linden/Caps/BunchOfCaps/BunchOfCaps.cs
@@ -411,7 +411,7 @@ namespace OpenSim.Region.ClientStack.Linden
         {
             try
             {
-//                m_log.Debug("[CAPS]: ScriptTaskInventory Request in region: " + m_regionName);
+                //m_log.Debug("[CAPS]: ScriptTaskInventory Request in region: " + m_regionName);
                 //m_log.DebugFormat("[CAPS]: request: {0}, path: {1}, param: {2}", request, path, param);
 
                 Hashtable hash = (Hashtable)LLSD.LLSDDeserialize(Utils.StringToBytes(request));
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
index 645d00b..d0902ff 100755
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
@@ -4482,7 +4482,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             Utils.FloatToBytesSafepos(hover, data, pos); pos += 4;
 
             buf.DataLength = pos;
-            m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task | ThrottleOutPacketType.HighPriority, null, false, true);
+            m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task | ThrottleOutPacketType.HighPriority, null, true);
         }
 
         static private readonly byte[] AvatarAnimationHeader = new byte[] {
@@ -4638,7 +4638,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             CreateImprovedTerseBlock(ent, buf.Data, ref pos, false);
 
             buf.DataLength = pos;
-            m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, false, true);
+            m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, true);
         }
 
         //UUID m_courseLocationPrey = UUID.Zero;
@@ -5197,7 +5197,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
                         m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task,
                             //delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, false, false);
-                            null, false, false);
+                            null, false);
 
                         buf = newbuf;
                         zc.Data = buf.Data;
@@ -5221,7 +5221,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     buf.DataLength = zc.Finish();
                     m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task,
                         //delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, false, false);
-                        null, false, false);
+                        null, false);
                 }
             }
 
@@ -5359,7 +5359,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
                         m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task,
                             //delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, false, false);
-                            null, false, false);
+                            null, false);
 
                         buf = newbuf;
                         zc.Data = buf.Data;
@@ -5383,7 +5383,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     buf.DataLength = zc.Finish();
                     m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task,
                         //delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, false, false);
-                        null, false, false);
+                        null, false);
                 }
             }
 
@@ -5432,7 +5432,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
                         buf.Data[countposition] = (byte)count;
                         buf.DataLength = pos;
-                        m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, false, false);
+                        m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, false);
 
                         buf = newbuf;
                         data = buf.Data;
@@ -5446,7 +5446,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 {
                     buf.Data[countposition] = (byte)count;
                     buf.DataLength = pos;
-                    m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, false, false);
+                    m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, false);
                 }
             }
 
@@ -5493,8 +5493,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                         buf.DataLength = lastpos;
                         // zero encode is not as spec
                         m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task,
-                            //delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, false, true);
-                            null, false, true);
+                            delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, true);
+                            //null, false, true);
 
                         tau = new List<EntityUpdate>(30);
                         tau.Add(eu);
@@ -5509,8 +5509,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     buf.Data[17] = (byte)count;
                     buf.DataLength = pos;
                     m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task,
-                        //delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, false, true);
-                        null, false, true);
+                        //delegate (OutgoingPacket oPacket) { ResendPrimUpdates(tau, oPacket); }, true);
+                        null, true);
                 }
             }
 
@@ -14541,7 +14541,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             LLUDPServer.LogPacketHeader(false, m_circuitCode, 0, packet.Type, (ushort)packet.Length);
             #endregion BinaryStats
 
-            OutPacket(packet, throttlePacketType, true);
+            OutPacket(packet, throttlePacketType, true, null);
         }
 
         /// <summary>
@@ -15174,7 +15174,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 int pos = 18;
                 CreateImprovedTerseBlock(p, buf.Data, ref pos, false);
                 buf.DataLength = pos;
-                m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, false, true);
+                m_udpServer.SendUDPPacket(m_udpClient, buf, ThrottleOutPacketType.Task, null, true);
             }
         }
 
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs
index 69e53f6..af62d9c 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPClient.cs
@@ -115,7 +115,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// <summary>Circuit code that this client is connected on</summary>
         public readonly uint CircuitCode;
         /// <summary>Sequence numbers of packets we've received (for duplicate checking)</summary>
-        public IncomingPacketHistoryCollection PacketArchive = new IncomingPacketHistoryCollection(256);
+        public IncomingPacketHistoryCollection PacketArchive = new IncomingPacketHistoryCollection(1024);
 
         /// <summary>Packets we have sent that need to be ACKed by the client</summary>
         public UnackedPacketCollection NeedAcks = new UnackedPacketCollection();
@@ -123,6 +123,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// <summary>ACKs that are queued up, waiting to be sent to the client</summary>
         public DoubleLocklessQueue<uint> PendingAcks = new DoubleLocklessQueue<uint>();
 
+        public int AckStalls;
+
         /// <summary>Current packet sequence number</summary>
         public int CurrentSequence;
         /// <summary>Current ping sequence number</summary>
@@ -185,7 +187,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         private byte[] m_packedThrottles;
 
         private int m_defaultRTO = 1000; // 1sec is the recommendation in the RFC
-        private int m_maxRTO = 10000;
+        private int m_maxRTO = 3000;
+        private int m_minRTO = 250;
         public bool m_deliverPackets = true;
 
         private float m_burstTime;
@@ -538,46 +541,20 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// true if the packet has been queued,
         /// false if the packet has not been queued and should be sent immediately.
         /// </returns>
-        public bool EnqueueOutgoing(OutgoingPacket packet, bool forceQueue)
+        public bool EnqueueOutgoing(OutgoingPacket packet)
         {
-            return EnqueueOutgoing(packet, forceQueue, false);
+            return EnqueueOutgoing(packet, false);
         }
 
-        public bool EnqueueOutgoing(OutgoingPacket packet, bool forceQueue, bool highPriority)
+        public bool EnqueueOutgoing(OutgoingPacket packet, bool highPriority)
         {
             int category = (int)packet.Category;
 
             if (category >= 0 && category < m_packetOutboxes.Length)
             {
                 DoubleLocklessQueue<OutgoingPacket> queue = m_packetOutboxes[category];
-
-                if (forceQueue || m_deliverPackets == false)
-                {
-                    queue.Enqueue(packet, highPriority);
-                    return true;
-                }
-
-                // need to enqueue if queue is not empty
-                if (queue.Count > 0 || m_nextPackets[category] != null)
-                {
-                    queue.Enqueue(packet, highPriority);
-                    return true;
-                }
-
-                // check bandwidth
-                TokenBucket bucket = m_throttleCategories[category];
-                if (bucket.CheckTokens(packet.Buffer.DataLength))
-                {
-                    // enough tokens so it can be sent imediatly by caller
-                    bucket.RemoveTokens(packet.Buffer.DataLength);
-                    return false;
-                }
-                else
-                {
-                    // Force queue specified or not enough tokens in the bucket, queue this packet
-                    queue.Enqueue(packet, highPriority);
-                    return true;
-                }
+                queue.Enqueue(packet, highPriority);
+                return true;
             }
             else
             {
@@ -608,33 +585,84 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             OutgoingPacket packet = null;
             DoubleLocklessQueue<OutgoingPacket> queue;
-            TokenBucket bucket;
             bool packetSent = false;
             ThrottleOutPacketTypeFlags emptyCategories = 0;
 
             //string queueDebugOutput = String.Empty; // Serious debug business
+            // do resends
 
-            for (int i = 0; i < THROTTLE_CATEGORY_COUNT; i++)
+            packet = m_nextPackets[0];
+            if (packet != null)
+            {
+                if (packet.Buffer != null)
+                {
+                    if (m_throttleCategories[0].RemoveTokens(packet.Buffer.DataLength))
+                    {
+                        // Send the packet
+                        m_udpServer.SendPacketFinal(packet);
+                        packetSent = true;
+                        m_nextPackets[0] = null;
+                    }
+                }
+                else
+                    m_nextPackets[0] = null;
+            }
+            else
+            {
+                queue = m_packetOutboxes[0];
+                if (queue != null)
+                {
+                    if(queue.Dequeue(out packet))
+                    {
+                        // A packet was pulled off the queue. See if we have
+                        // enough tokens in the bucket to send it out
+                        if (packet.Buffer != null)
+                        {
+                            if (m_throttleCategories[0].RemoveTokens(packet.Buffer.DataLength))
+                            {
+                                // Send the packet
+                                m_udpServer.SendPacketFinal(packet);
+                                packetSent = true;
+                            }
+                            else
+                            {
+                                // Save the dequeued packet for the next iteration
+                                m_nextPackets[0] = packet;
+                            }
+                        }
+                    }
+                }
+                else
+                {
+                    m_packetOutboxes[0] = new DoubleLocklessQueue<OutgoingPacket>();
+                }
+            }
+
+            if(NeedAcks.Count() > 50)
+            {
+                Interlocked.Increment(ref AckStalls);
+                return true;
+            }
+
+            for (int i = 1; i < THROTTLE_CATEGORY_COUNT; i++)
             {
-                bucket = m_throttleCategories[i];
                 //queueDebugOutput += m_packetOutboxes[i].Count + " ";  // Serious debug business
 
-                if (m_nextPackets[i] != null)
+                packet = m_nextPackets[i];
+                if (packet != null)
                 {
-                    // This bucket was empty the last time we tried to send a packet,
-                    // leaving a dequeued packet still waiting to be sent out. Try to
-                    // send it again
-                    OutgoingPacket nextPacket = m_nextPackets[i];
-                    if(nextPacket.Buffer == null)
+                    if(packet.Buffer == null)
                     {
                         if (m_packetOutboxes[i].Count < 5)
                             emptyCategories |= CategoryToFlag(i);
+                        m_nextPackets[i] = null;
                         continue;
                     }
-                    if (bucket.RemoveTokens(nextPacket.Buffer.DataLength))
+
+                    if (m_throttleCategories[i].RemoveTokens(packet.Buffer.DataLength))
                     {
                         // Send the packet
-                        m_udpServer.SendPacketFinal(nextPacket);
+                        m_udpServer.SendPacketFinal(packet);
                         m_nextPackets[i] = null;
                         packetSent = true;
 
@@ -647,55 +675,34 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     // No dequeued packet waiting to be sent, try to pull one off
                     // this queue
                     queue = m_packetOutboxes[i];
-                    if (queue != null)
+                    if(queue.Dequeue(out packet))
                     {
-                        bool success = false;
-                        try
-                        {
-                            success = queue.Dequeue(out packet);
-                        }
-                        catch
+                        if (packet.Buffer == null)
                         {
-                            m_packetOutboxes[i] = new DoubleLocklessQueue<OutgoingPacket>();
+                            // packet canceled elsewhere (by a ack for example)
+                            if (queue.Count < 5)
+                                emptyCategories |= CategoryToFlag(i);
+                            continue;
                         }
-                        if (success)
+
+                        if (m_throttleCategories[i].RemoveTokens(packet.Buffer.DataLength))
                         {
-                            // A packet was pulled off the queue. See if we have
-                            // enough tokens in the bucket to send it out
-                            if(packet.Buffer == null)
-                            {
-                                // packet canceled elsewhere (by a ack for example)
-                                if (queue.Count < 5)
-                                    emptyCategories |= CategoryToFlag(i);
-                            }
-                            else
-                            {
-                                if (bucket.RemoveTokens(packet.Buffer.DataLength))
-                                {
-                                    // Send the packet
-                                    m_udpServer.SendPacketFinal(packet);
-                                    packetSent = true;
-
-                                    if (queue.Count < 5)
-                                        emptyCategories |= CategoryToFlag(i);
-                                }
-                                else
-                                {
-                                    // Save the dequeued packet for the next iteration
-                                    m_nextPackets[i] = packet;
-                                }
-                            }
+                            // Send the packet
+                            m_udpServer.SendPacketFinal(packet);
+                            packetSent = true;
+                            if (queue.Count < 5)
+                                emptyCategories |= CategoryToFlag(i);
                         }
                         else
                         {
-                            // No packets in this queue. Fire the queue empty callback
-                            // if it has not been called recently
-                            emptyCategories |= CategoryToFlag(i);
+                            // Save the dequeued packet for the next iteration
+                            m_nextPackets[i] = packet;
                         }
                     }
                     else
                     {
-                        m_packetOutboxes[i] = new DoubleLocklessQueue<OutgoingPacket>();
+                        // No packets in this queue. Fire the queue empty callback
+                        // if it has not been called recently
                         emptyCategories |= CategoryToFlag(i);
                     }
                 }
@@ -718,8 +725,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             p *= 5;
             if( p> m_maxRTO)
                 p = m_maxRTO;
-            else if(p < m_defaultRTO)
-                p = m_defaultRTO;
+            else if(p < m_minRTO)
+                p = m_minRTO;
 
             m_RTO = p;
         }
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
index 2863b8d..6994efb 100755
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
@@ -880,8 +880,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             // If a Linden Lab 1.23.5 client receives an update packet after a kill packet for an object, it will
             // continue to display the deleted object until relog.  Therefore, we need to always queue a kill object
             // packet so that it isn't sent before a queued update packet.
-            bool requestQueue = type == PacketType.KillObject;
-            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, requestQueue, highPriority))
+            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, highPriority))
             {
                 SendPacketFinal(outgoingPacket);
                 return true;
@@ -952,7 +951,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         }
 
         public void SendUDPPacket(
-            LLUDPClient udpClient, UDPPacketBuffer buffer, ThrottleOutPacketType category, UnackedPacketMethod method, bool forcequeue, bool zerocode)
+            LLUDPClient udpClient, UDPPacketBuffer buffer, ThrottleOutPacketType category, UnackedPacketMethod method, bool zerocode)
         {
             bool highPriority = false;
 
@@ -971,7 +970,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             if ((outgoingPacket.Buffer.Data[0] & Helpers.MSG_RELIABLE) != 0)
                 outgoingPacket.UnackedMethod = ((method == null) ? delegate (OutgoingPacket oPacket) { ResendUnacked(oPacket); } : method);
 
-            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, forcequeue, highPriority))
+            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, highPriority))
                 SendPacketFinal(outgoingPacket);
         }
 
@@ -991,7 +990,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             if ((outgoingPacket.Buffer.Data[0] & Helpers.MSG_RELIABLE) != 0)
                 outgoingPacket.UnackedMethod = delegate (OutgoingPacket oPacket) { ResendUnacked(oPacket); };
 
-            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, false, highPriority))
+            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, highPriority))
                 SendPacketFinal(outgoingPacket);
         }
 
@@ -1056,11 +1055,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             data[7] = udpClient.CurrentPingSequence++;
             // older seq number of our un ack packets, so viewers could clean deduplication lists TODO
-            //Utils.UIntToBytes(0, data, 8);
-            data[8] = 0;
-            data[9] = 0;
-            data[10] = 0;
-            data[11] = 0;
+            Utils.UIntToBytes(udpClient.NeedAcks.Oldest(), data, 8);
 
             buf.DataLength = 12;
             SendUDPPacket(udpClient, buf, ThrottleOutPacketType.Unknown);
@@ -1140,7 +1135,6 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             // Bump up the resend count on this packet
             Interlocked.Increment(ref outgoingPacket.ResendCount);
-
             // Requeue or resend the packet
             if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, false))
                 SendPacketFinal(outgoingPacket);
@@ -1162,7 +1156,10 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 return;
             LLUDPClient udpClient = outgoingPacket.Client;
             if (!udpClient.IsConnected)
+            {
+                FreeUDPBuffer(buffer);
                 return;
+            }
 
             byte flags = buffer.Data[0];
             bool isResend = (flags & Helpers.MSG_RESENT) != 0;
@@ -1172,7 +1169,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             int dataLength = buffer.DataLength;
 
             // only append acks on plain reliable messages
-            if (flags == Helpers.MSG_RELIABLE)
+            if (flags == Helpers.MSG_RELIABLE && outgoingPacket.UnackedMethod == null)
             {
                 // Keep appending ACKs until there is no room left in the buffer or there are
                 // no more ACKs to append
@@ -1211,10 +1208,12 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             // Stats tracking
             Interlocked.Increment(ref udpClient.PacketsSent);
             PacketsSentCount++;
+
             SyncSend(buffer);
 
             // Keep track of when this packet was sent out (right now)
-            outgoingPacket.TickCount = Environment.TickCount & Int32.MaxValue;
+            int enow = Environment.TickCount & Int32.MaxValue;
+            Interlocked.Exchange(ref outgoingPacket.TickCount, enow);
 
             if (outgoingPacket.UnackedMethod == null)
                 FreeUDPBuffer(buffer);
@@ -1935,7 +1934,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     {
                         m_resendUnacked = true;
                         m_elapsedMSOutgoingPacketHandler = 0.0;
-                        m_elapsed100MSOutgoingPacketHandler += 1;
+                        ++m_elapsed100MSOutgoingPacketHandler;
                     }
 
                     // Check for pending outgoing ACKs every 500ms
@@ -1943,7 +1942,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     {
                         m_sendAcks = true;
                         m_elapsed100MSOutgoingPacketHandler = 0;
-                        m_elapsed500MSOutgoingPacketHandler += 1;
+                        ++m_elapsed500MSOutgoingPacketHandler;
                     }
 
                     // Send pings to clients every 5000ms
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/UnackedPacketCollection.cs b/OpenSim/Region/ClientStack/Linden/UDP/UnackedPacketCollection.cs
index 32a6c40..af5b2ae 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/UnackedPacketCollection.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/UnackedPacketCollection.cs
@@ -66,21 +66,31 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         //private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
         /// <summary>Holds the actual unacked packet data, sorted by sequence number</summary>
-        private Dictionary<uint, OutgoingPacket> m_packets = new Dictionary<uint, OutgoingPacket>();
+        private SortedDictionary<uint, OutgoingPacket> m_packets = new SortedDictionary<uint, OutgoingPacket>();
         /// <summary>Holds packets that need to be added to the unacknowledged list</summary>
         private LocklessQueue<OutgoingPacket> m_pendingAdds = new LocklessQueue<OutgoingPacket>();
         /// <summary>Holds information about pending acknowledgements</summary>
         private LocklessQueue<PendingAck> m_pendingAcknowledgements = new LocklessQueue<PendingAck>();
         /// <summary>Holds information about pending removals</summary>
         private LocklessQueue<uint> m_pendingRemoves = new LocklessQueue<uint>();
-
-
+        private uint m_older;
         public void Clear()
         {
             m_packets.Clear();
             m_pendingAdds = null;
             m_pendingAcknowledgements = null;
             m_pendingRemoves = null;
+            m_older = 0;
+        }
+
+        public int Count()
+        {
+            return m_packets.Count + m_pendingAdds.Count - m_pendingAcknowledgements.Count - m_pendingRemoves.Count;
+        }
+
+        public uint Oldest()
+        {
+            return m_older;
         }
 
         /// <summary>
@@ -148,33 +158,47 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             ProcessQueues();
 
             List<OutgoingPacket> expiredPackets = null;
-
+            bool doolder = true;
             if (m_packets.Count > 0)
             {
                 int now = Environment.TickCount & Int32.MaxValue;
 
                 foreach (OutgoingPacket packet in m_packets.Values)
                 {
+                    if(packet.Buffer == null)
+                    {
+                        Remove(packet.SequenceNumber);
+                        continue;
+                    }
+
+                    if(doolder)
+                    {
+                        m_older = packet.SequenceNumber;
+                        doolder = false;
+                    }
+
                     // TickCount of zero means a packet is in the resend queue
                     // but hasn't actually been sent over the wire yet
-                    if (packet.TickCount == 0)
+                    int ptime = Interlocked.Exchange(ref packet.TickCount, 0);
+                    if (ptime == 0)
                         continue;
 
-                    if (now - packet.TickCount >= timeoutMS)
+                    if(now - ptime < timeoutMS)
                     {
-                        if (expiredPackets == null)
-                            expiredPackets = new List<OutgoingPacket>();
+                        int t = Interlocked.Exchange(ref packet.TickCount, ptime);
+                        if (t > ptime)
+                            Interlocked.Exchange(ref packet.TickCount, t);
+                        continue;
+                    }
 
-                        // The TickCount will be set to the current time when the packet
-                        // is actually sent out again
-                        packet.TickCount = 0;
+                    if (expiredPackets == null)
+                        expiredPackets = new List<OutgoingPacket>();
 
-                        // As with other network applications, assume that an expired packet is
-                        // an indication of some network problem, slow transmission
-                        packet.Client.FlowThrottle.ExpirePackets(1);
+                    // As with other network applications, assume that an expired packet is
+                    // an indication of some network problem, slow transmission
+                    packet.Client.FlowThrottle.ExpirePackets(1);
 
-                        expiredPackets.Add(packet);
-                    }
+                    expiredPackets.Add(packet);
                 }
             }
 
@@ -186,65 +210,50 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
         private void ProcessQueues()
         {
+            while (m_pendingRemoves.TryDequeue(out uint pendingRemove))
+            {
+                if (m_packets.TryGetValue(pendingRemove, out OutgoingPacket removedPacket))
+                {
+                    m_packets.Remove(pendingRemove);
+                    if (removedPacket != null)
+                    {
+                        // Update stats
+                        Interlocked.Add(ref removedPacket.Client.UnackedBytes, -removedPacket.Buffer.DataLength);
+
+                        removedPacket.Client.FreeUDPBuffer(removedPacket.Buffer);
+                        removedPacket.Buffer = null;
+                    }
+                }
+            }
+
             // Process all the pending adds
-            OutgoingPacket pendingAdd;
-            while (m_pendingAdds.TryDequeue(out pendingAdd))
+            while (m_pendingAdds.TryDequeue(out OutgoingPacket pendingAdd))
             {
                 if (pendingAdd != null)
                     m_packets[pendingAdd.SequenceNumber] = pendingAdd;
             }
 
             // Process all the pending removes, including updating statistics and round-trip times
-            PendingAck pendingAcknowledgement;
-            while (m_pendingAcknowledgements.TryDequeue(out pendingAcknowledgement))
+            while (m_pendingAcknowledgements.TryDequeue(out PendingAck pendingAcknowledgement))
             {
                 //m_log.DebugFormat("[UNACKED PACKET COLLECTION]: Processing ack {0}", pendingAcknowledgement.SequenceNumber);
-                OutgoingPacket ackedPacket;
-                if (m_packets.TryGetValue(pendingAcknowledgement.SequenceNumber, out ackedPacket))
+                if (m_packets.TryGetValue(pendingAcknowledgement.SequenceNumber, out OutgoingPacket ackedPacket))
                 {
+                    m_packets.Remove(pendingAcknowledgement.SequenceNumber);
                     if (ackedPacket != null)
                     {
-                        m_packets.Remove(pendingAcknowledgement.SequenceNumber);
-
                         // Update stats
-                        Interlocked.Add(ref ackedPacket.Client.UnackedBytes, -ackedPacket.Buffer.DataLength);
-
-                        ackedPacket.Client.FreeUDPBuffer(ackedPacket.Buffer);
-                        ackedPacket.Buffer = null;
+                        if(ackedPacket.Buffer != null)
+                        {
+                            Interlocked.Add(ref ackedPacket.Client.UnackedBytes, -ackedPacket.Buffer.DataLength);
 
+                            ackedPacket.Client.FreeUDPBuffer(ackedPacket.Buffer);
+                            ackedPacket.Buffer = null;
+                        }
                         // As with other network applications, assume that an acknowledged packet is an
                         // indication that the network can handle a little more load, speed up the transmission
                         ackedPacket.Client.FlowThrottle.AcknowledgePackets(1);
                     }
-                    else
-                    {
-                        // m_log.WarnFormat("[UNACKED PACKET COLLECTION]: found null packet for sequence number {0} to ack",
-                        //                  pendingAcknowledgement.SequenceNumber);
-                    }
-                }
-                else
-                {
-                    // m_log.WarnFormat("[UNACKED PACKET COLLECTION]: Could not find packet with sequence number {0} to ack",
-                    //                  pendingAcknowledgement.SequenceNumber);
-                }
-            }
-
-            uint pendingRemove;
-            while(m_pendingRemoves.TryDequeue(out pendingRemove))
-            {
-                OutgoingPacket removedPacket;
-                if (m_packets.TryGetValue(pendingRemove, out removedPacket))
-                {
-                    if (removedPacket != null)
-                    {
-                        m_packets.Remove(pendingRemove);
-
-                        // Update stats
-                        Interlocked.Add(ref removedPacket.Client.UnackedBytes, -removedPacket.Buffer.DataLength);
-
-                        removedPacket.Client.FreeUDPBuffer(removedPacket.Buffer);
-                        removedPacket.Buffer = null;
-                    }
                 }
             }
         }