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Revamp packet handler to smooth out the stream of resent packets. 

Eliminates the bursting in resends observed in the prior implementation
0.6.1-post-fixes
Melanie Thielker 2008-12-17 17:19:14 +00:00
parent 72ff5322f5
commit 35ec496f98
1 changed files with 63 additions and 45 deletions
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108
OpenSim/Region/ClientStack/LindenUDP/LLPacketHandler.cs
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@ -54,7 +54,6 @@ namespace OpenSim.Region.ClientStack.LindenUDP
int PacketsReceived { get; } int PacketsReceived { get; }
int PacketsReceivedReported { get; } int PacketsReceivedReported { get; }
uint SilenceLimit { get; set; }
uint ResendTimeout { get; set; } uint ResendTimeout { get; set; }
bool ReliableIsImportant { get; set; } bool ReliableIsImportant { get; set; }
int MaxReliableResends { get; set; } int MaxReliableResends { get; set; }
@ -124,7 +123,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
/// <summary> /// <summary>
/// The number of milliseconds that can pass before a packet that needs an ack is resent. /// The number of milliseconds that can pass before a packet that needs an ack is resent.
/// </param> /// </param>
private uint m_ResendTimeout = 2000; private uint m_ResendTimeout = 4000;
public uint ResendTimeout public uint ResendTimeout
{ {
@ -132,14 +131,6 @@ namespace OpenSim.Region.ClientStack.LindenUDP
set { m_ResendTimeout = value; } set { m_ResendTimeout = value; }
} }
private uint m_SilenceLimit = 250;
public uint SilenceLimit
{
get { return m_SilenceLimit; }
set { m_SilenceLimit = value; }
}
private int m_MaxReliableResends = 3; private int m_MaxReliableResends = 3;
public int MaxReliableResends public int MaxReliableResends
@ -148,8 +139,6 @@ namespace OpenSim.Region.ClientStack.LindenUDP
set { m_MaxReliableResends = value; } set { m_MaxReliableResends = value; }
} }
private int m_LastAck = 0;
// Track duplicated packets. This uses a Dictionary. Both insertion // Track duplicated packets. This uses a Dictionary. Both insertion
// and lookup are common operations and need to take advantage of // and lookup are common operations and need to take advantage of
// the hashing. Expiration is less common and can be allowed the // the hashing. Expiration is less common and can be allowed the
@ -168,6 +157,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
private int m_PacketsSentReported = 0; private int m_PacketsSentReported = 0;
private int m_UnackedBytes = 0; private int m_UnackedBytes = 0;
private int m_LastResend = 0;
public int PacketsReceived public int PacketsReceived
{ {
get { return m_PacketsReceived; } get { return m_PacketsReceived; }
@ -211,6 +202,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
set { m_ReliableIsImportant = value; } set { m_ReliableIsImportant = value; }
} }
private int m_DropSafeTimeout;
LLPacketServer m_PacketServer; LLPacketServer m_PacketServer;
private byte[] m_ZeroOutBuffer = new byte[4096]; private byte[] m_ZeroOutBuffer = new byte[4096];
@ -222,6 +215,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
{ {
m_Client = client; m_Client = client;
m_PacketServer = server; m_PacketServer = server;
m_DropSafeTimeout = System.Environment.TickCount + 15000;
m_PacketQueue = new LLPacketQueue(client.AgentId, userSettings); m_PacketQueue = new LLPacketQueue(client.AgentId, userSettings);
@ -235,6 +229,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
m_PacketQueue.Enqueue(null); m_PacketQueue.Enqueue(null);
m_PacketQueue.Close(); m_PacketQueue.Close();
m_Client = null;
} }
// Send one packet. This actually doesn't send anything, it queues // Send one packet. This actually doesn't send anything, it queues
@ -327,15 +322,39 @@ namespace OpenSim.Region.ClientStack.LindenUDP
private void ResendUnacked() private void ResendUnacked()
{ {
int now = System.Environment.TickCount; int now = System.Environment.TickCount;
int lastAck = m_LastAck;
int intervalMs = 250;
if (m_LastResend != 0)
intervalMs = now - m_LastResend;
lock (m_NeedAck)
{
if (m_DropSafeTimeout > now ||
intervalMs > 500) // We were frozen!
{
foreach (AckData data in new List<AckData>
(m_NeedAck.Values))
{
if (m_DropSafeTimeout > now)
{
m_NeedAck[data.Packet.Header.Sequence].
TickCount = now;
}
else
{
m_NeedAck[data.Packet.Header.Sequence].
TickCount += intervalMs;
}
}
}
}
m_LastResend = now;
// Unless we have received at least one ack, don't bother resending // Unless we have received at least one ack, don't bother resending
// anything. There may not be a client there, don't clog up the // anything. There may not be a client there, don't clog up the
// pipes. // pipes.
// //
if (lastAck == 0)
return;
lock (m_NeedAck) lock (m_NeedAck)
{ {
// Nothing to do // Nothing to do
@ -343,16 +362,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
if (m_NeedAck.Count == 0) if (m_NeedAck.Count == 0)
return; return;
// If we have seen no acks in <SilenceLimit> s but are int resent = 0;
// waiting for acks, then there may be no one listening.
// No need to resend anything. Keep it until it gets stale,
// then it will be dropped.
//
if ((((now - lastAck) > m_SilenceLimit) &&
m_NeedAck.Count > 0) || m_NeedAck.Count == 0)
{
return;
}
foreach (AckData data in new List<AckData>(m_NeedAck.Values)) foreach (AckData data in new List<AckData>(m_NeedAck.Values))
{ {
@ -362,25 +372,35 @@ namespace OpenSim.Region.ClientStack.LindenUDP
// //
if ((now - data.TickCount) > m_ResendTimeout) if ((now - data.TickCount) > m_ResendTimeout)
{ {
m_NeedAck[packet.Header.Sequence].Resends++; if (resent < 20)
// The client needs to be told that a packet is being resent, otherwise it appears to believe
// that it should reset its sequence to that packet number.
packet.Header.Resent = true;
if (m_NeedAck[packet.Header.Sequence].Resends >=
m_MaxReliableResends && (!m_ReliableIsImportant))
{ {
m_NeedAck.Remove(packet.Header.Sequence); m_NeedAck[packet.Header.Sequence].Resends++;
TriggerOnPacketDrop(packet, data.Identifier);
continue; // The client needs to be told that a packet is being resent, otherwise it appears to believe
// that it should reset its sequence to that packet number.
packet.Header.Resent = true;
if ((m_NeedAck[packet.Header.Sequence].Resends >=
m_MaxReliableResends) && (!m_ReliableIsImportant))
{
m_NeedAck.Remove(packet.Header.Sequence);
TriggerOnPacketDrop(packet, data.Identifier);
continue;
}
m_NeedAck[packet.Header.Sequence].TickCount =
System.Environment.TickCount;
QueuePacket(packet, ThrottleOutPacketType.Resend,
data.Identifier);
resent++;
}
else
{
m_NeedAck[packet.Header.Sequence].TickCount +=
intervalMs;
} }
m_NeedAck[packet.Header.Sequence].TickCount =
System.Environment.TickCount;
QueuePacket(packet, ThrottleOutPacketType.Resend,
data.Identifier);
} }
} }
} }
@ -623,8 +643,6 @@ namespace OpenSim.Region.ClientStack.LindenUDP
m_NeedAck.Remove(id); m_NeedAck.Remove(id);
m_UnackedBytes -= packet.ToBytes().Length; m_UnackedBytes -= packet.ToBytes().Length;
m_LastAck = System.Environment.TickCount;
} }
} }