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Overhaul client latency calculations.

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The ping/pong orders are replaced with a dedicated
(and much smaller) Ping packet that is handled
directly in the client and server Connection wrappers.

This allows clients to respond when the orders are
processed, instead of queuing the pong order to be
sent in the next frame (which added an extra 120ms
of unwanted latency).

The ping frequency has been raised to 1Hz, and pings
are now routed through the server events queue in
preparation for the future dynamic latency system.

The raw ping numbers are no longer sent to clients,
the server instead evaluates a single ConnectionQuality
value that in the future may be based on more than
just the ping times.
This commit is contained in:
Paul Chote
2021-09-20 22:44:49 +01:00
committed by abcdefg30
parent 67face8cf0
commit df798fb620
12 changed files with 161 additions and 150 deletions
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39
OpenRA.Game/Server/Connection.cs
View File

@@ -12,6 +12,8 @@
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
@@ -23,6 +25,9 @@ namespace OpenRA.Server
{
public const int MaxOrderLength = 131072;
// Cap ping history at 15 seconds as a balance between expiring stale state and having enough data for decent statistics
const int MaxPingSamples = 15;
public readonly int PlayerIndex;
public readonly string AuthToken;
public readonly EndPoint EndPoint;
@@ -36,6 +41,7 @@ namespace OpenRA.Server
long lastReceivedTime = 0;
readonly BlockingCollection<byte[]> sendQueue = new BlockingCollection<byte[]>();
readonly Queue<int> pingHistory = new Queue<int>();
public Connection(Server server, Socket socket, string authToken)
{
@@ -50,6 +56,17 @@ namespace OpenRA.Server
}.Start((server, socket));
}
static byte[] CreatePingFrame()
{
var ms = new MemoryStream(21);
ms.WriteArray(BitConverter.GetBytes(13));
ms.WriteArray(BitConverter.GetBytes(0));
ms.WriteArray(BitConverter.GetBytes(0));
ms.WriteByte((byte)OrderType.Ping);
ms.WriteArray(BitConverter.GetBytes(Game.RunTime));
return ms.GetBuffer();
}
void SendReceiveLoop(object s)
{
var (server, socket) = (ValueTuple<Server, Socket>)s;
@@ -61,6 +78,7 @@ namespace OpenRA.Server
var state = ReceiveState.Header;
var expectLength = 8;
var frame = 0;
var lastPingSent = Stopwatch.StartNew();
try
{
@@ -107,7 +125,19 @@ namespace OpenRA.Server
case ReceiveState.Data:
{
server.OnConnectionPacket(this, frame, bytes);
// Ping packets are sent and processed internally within this thread to reduce
// server-introduced latencies from polling loops
if (expectLength == 9 && bytes[0] == (byte)OrderType.Ping)
{
if (pingHistory.Count == MaxPingSamples)
pingHistory.Dequeue();
pingHistory.Enqueue((int)(Game.RunTime - BitConverter.ToInt64(bytes, 1)));
server.OnConnectionPing(this, pingHistory.ToArray());
}
else
server.OnConnectionPacket(this, frame, bytes);
expectLength = 8;
state = ReceiveState.Header;
@@ -121,6 +151,13 @@ namespace OpenRA.Server
if (sendQueue.IsCompleted)
return;
// Regularly check player ping
if (lastPingSent.ElapsedMilliseconds > 1000)
{
sendQueue.Add(CreatePingFrame());
lastPingSent.Restart();
}
// Send all data immediately, we will block again on read
while (sendQueue.TryTake(out var data, 0))
{