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fix: Fixes timer orphaning issue (#1196)

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* Fixes an edge case where a check to see if a timer was being executed resulted in it not being properly detached on stop. Fixed this by changing how we determine what timer is currently being executed.
* Adds execution count to #DEBUG_TIMERS so shards can get notified (rudimentarily for now) about sequentially executing long chains of timers.

Unfortunately, for now, there is no good option when it comes to executing timers. If we execute let's say 500, and defer the rest, that makes all timers effectively 8ms off until it "catches up". Depending on the shard, that may never happen.
This commit is contained in:
Kamron Batman 2022-10-18 18:14:26 -07:00 • committed by GitHub
parent 919b7e9416
commit 791128f238
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 39 additions and 29 deletions
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2
Projects/Server/Timer/Timer.DelayCall.cs
View file

@ -16,8 +16,8 @@
using System;
#if DEBUG_TIMERS
using System.Collections.Generic;
#endif
using System.Diagnostics;
#endif
using System.Runtime.CompilerServices;
namespace Server;

44
Projects/Server/Timer/Timer.TimerWheel.cs
View file

@ -22,6 +22,9 @@ namespace Server;
public partial class Timer
{
#if DEBUG_TIMERS
private const int _chainExecutionThreshold = 512;
#endif
private const int _ringSizePowerOf2 = 12;
private const int _ringSize = 1 << _ringSizePowerOf2; // 4096
private const int _ringLayers = 3;
@ -33,7 +36,6 @@ public partial class Timer
private static Timer[] _executingRings = new Timer[_ringLayers];
private static long _lastTickTurned = -1;
private static bool _timerWheelExecuting;
public static void Init(long tickCount)
{
@ -59,7 +61,6 @@ public partial class Timer
private static void Turn()
{
_timerWheelExecuting = true;
var turnNextWheel = false;
// Detach the chain from the timer wheel. This allows adding timers to the same slot during execution.
@ -86,15 +87,19 @@ public partial class Timer
for (var i = 0; i < _ringLayers; i++)
{
var timer = _executingRings[i];
if (timer == null)
#if DEBUG_TIMERS
var executionCount = 0;
#endif
while (_executingRings[i] != null)
{
continue;
}
#if DEBUG_TIMERS
executionCount++;
#endif
do
{
var next = timer._nextTimer;
var timer = _executingRings[i];
// Set the executing timer to the next in the link list because we will be detaching.
_executingRings[i] = timer._nextTimer;
timer.Detach();
@ -116,15 +121,18 @@ public partial class Timer
{
timer.OnDetach();
}
timer = next;
} while (timer != null);
// Clear out the rings
_executingRings[i] = null;
}
#if DEBUG_TIMERS
if (executionCount > _chainExecutionThreshold)
{
logger.Warning(
"Timer threshold of {Threshold} met. Executed {Count} timers sequentially.",
_chainExecutionThreshold,
executionCount
);
}
#endif
}
_timerWheelExecuting = false;
}
private static void Execute(Timer timer)
@ -232,7 +240,7 @@ public partial class Timer
total++;
t = t?._nextTimer;
t = t._nextTimer;
}
}
}

22
Projects/Server/Timer/Timer.cs
View file

@ -153,20 +153,22 @@ public partial class Timer
Running = false;
// Do not detach if we are in the middle of executing the timer wheel for this ring/slot
if (!_timerWheelExecuting || _ringIndexes[_ring] != _slot)
// We are the head on the timer ring
if (_rings[_ring][_slot] == this)
{
// We are at the head
if (_rings[_ring][_slot] == this)
{
_rings[_ring][_slot] = _nextTimer;
}
Detach();
OnDetach();
_rings[_ring][_slot] = _nextTimer;
}
// We are the head on the executing ring
if (_executingRings[_ring] == this)
{
_executingRings[_ring] = _nextTimer;
}
Detach();
Version++;
OnDetach();
var prof = GetProfile();
if (prof != null)