Logger: Optimize Console/File logging targets

Implement a simple ObjectPool to pool up StringBuilders to avoid causing excessive GCing of gen1/2 items when large amounts of log entries are being generated.

We can also pre-determine the async overflow action at initialization time, allowing for an easy optimization in the message enqueue function, avoiding a number of comparisons.

Ryujinx.Common/Logging/Targets/AsyncLogTargetWrapper.cs

@@ -25,7 +25,7 @@ namespace Ryujinx.Common.Logging
 
         private BlockingCollection<LogEventArgs> _messageQueue;
 
-        private AsyncLogTargetOverflowAction _overflowAction;
+        private readonly int _overflowTimeout;
 
         public AsyncLogTargetWrapper(ILogTarget target)
             : this(target, -1, AsyncLogTargetOverflowAction.Block)
@@ -34,10 +34,8 @@ namespace Ryujinx.Common.Logging
         public AsyncLogTargetWrapper(ILogTarget target, int queueLimit, AsyncLogTargetOverflowAction overflowAction)
         {
             _target = target;
-
-            _overflowAction = overflowAction;
-
             _messageQueue = new BlockingCollection<LogEventArgs>(queueLimit);
+            _overflowTimeout = overflowAction == AsyncLogTargetOverflowAction.Block ? -1 : 0;
 
             _messageThread = new Thread(() => {
                 while (!_messageQueue.IsCompleted)
@@ -65,10 +63,7 @@ namespace Ryujinx.Common.Logging
         {
             if (!_messageQueue.IsAddingCompleted)
             {
-                if(!_messageQueue.TryAdd(e) && _overflowAction == AsyncLogTargetOverflowAction.Block)
-                {
-                    _messageQueue.Add(e);
-                }
+                _messageQueue.TryAdd(e, _overflowTimeout);
             }
         }
 

Ryujinx.Common/Logging/Targets/ConsoleLogTarget.cs

@@ -8,6 +8,8 @@ namespace Ryujinx.Common.Logging
 {
     public class ConsoleLogTarget : ILogTarget
     {
+        private static readonly ObjectPool<StringBuilder> _stringBuilderPool = SharedPools.Default<StringBuilder>();
+
         private static readonly ConcurrentDictionary<LogLevel, ConsoleColor> _logColors;
 
         static ConsoleLogTarget()
@@ -22,7 +24,11 @@ namespace Ryujinx.Common.Logging
 
         public void Log(object sender, LogEventArgs e)
         {
-            StringBuilder sb = new StringBuilder();
+            StringBuilder sb = _stringBuilderPool.Allocate();
+
+            try
+            {
+                sb.Clear();
 
                 sb.AppendFormat(@"{0:hh\:mm\:ss\.fff}", e.Time);
                 sb.Append(" | ");
@@ -64,6 +70,11 @@ namespace Ryujinx.Common.Logging
                     Console.WriteLine(sb.ToString());
                 }
             }
+            finally
+            {
+                _stringBuilderPool.Release(sb);
+            }
+        }
 
         public void Dispose()
         {

Ryujinx.Common/Logging/Targets/FileLogTarget.cs

@@ -6,9 +6,9 @@ namespace Ryujinx.Common.Logging
 {
     public class FileLogTarget : ILogTarget
     {
-        private StreamWriter _logWriter;
+        private static readonly ObjectPool<StringBuilder> _stringBuilderPool = SharedPools.Default<StringBuilder>();
 
-        public string Path { get; private set; }
+        private readonly StreamWriter _logWriter;
 
         public FileLogTarget(string path)
             : this(path, FileShare.Read, FileMode.Append)
@@ -16,14 +16,16 @@ namespace Ryujinx.Common.Logging
 
         public FileLogTarget(string path, FileShare fileShare, FileMode fileMode)
         {
-            this.Path = path;
-
-            this._logWriter = new StreamWriter(File.Open(path, fileMode, FileAccess.Write, fileShare));
+            _logWriter = new StreamWriter(File.Open(path, fileMode, FileAccess.Write, fileShare));
         }
 
         public void Log(object sender, LogEventArgs e)
         {
-            StringBuilder sb = new StringBuilder();
+            StringBuilder sb = _stringBuilderPool.Allocate();
+
+            try
+            {
+                sb.Clear();
 
                 sb.AppendFormat(@"{0:hh\:mm\:ss\.fff}", e.Time);
                 sb.Append(" | ");
@@ -55,6 +57,11 @@ namespace Ryujinx.Common.Logging
                 _logWriter.WriteLine(sb.ToString());
                 _logWriter.Flush();
             }
+            finally
+            {
+                _stringBuilderPool.Release(sb);
+            }
+        }
 
         public void Dispose()
         {

Ryujinx.Common/Pools/ObjectPool.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading;
+
+namespace Ryujinx.Common
+{
+    public class ObjectPool<T>
+        where T : class
+    {
+        private T _firstItem;
+        private readonly T[] _items;
+
+        private readonly Func<T> _factory;
+
+        public ObjectPool(Func<T> factory, int size)
+        {
+            _factory = factory;
+            _items = new T[size - 1];
+        }
+
+        public T Allocate()
+        {
+            var instance = _firstItem;
+
+            if (instance == null || instance != Interlocked.CompareExchange(ref _firstItem, null, instance))
+            {
+                instance = AllocateInternal();
+            }
+
+            return instance;
+        }
+
+        private T AllocateInternal()
+        {
+            var items = _items;
+
+            for (int i = 0; i < items.Length; i++)
+            {
+                var instance = items[i];
+
+                if (instance != null && instance == Interlocked.CompareExchange(ref items[i], null, instance))
+                {
+                    return instance;
+                }
+            }
+
+            return _factory();
+        }
+
+        public void Release(T obj)
+        {
+            if (_firstItem == null)
+            {
+                _firstItem = obj;
+            }
+            else
+            {
+                ReleaseInternal(obj);
+            }
+        }
+
+        private void ReleaseInternal(T obj)
+        {
+            var items = _items;
+
+            for (int i = 0; i < items.Length; i++)
+            {
+                if (items[i] == null)
+                {
+                    items[i] = obj;
+
+                    break;
+                }
+            }
+        }
+    }
+}

Ryujinx.Common/Pools/SharedPools.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Ryujinx.Common
+{
+    public static class SharedPools
+    {
+        private static class DefaultPool<T>
+            where T : class, new()
+        {
+            public static readonly ObjectPool<T> Instance = new ObjectPool<T>(() => new T(), 20);
+        }
+
+        public static ObjectPool<T> Default<T>() where T : class, new()
+        {
+            return DefaultPool<T>.Instance;
+        }
+    }
+}