Added configuration option "HighPrioritySocketThreads" (default 'true' = current behavior)

StackExchange.Redis/StackExchange/Redis/ConfigurationOptions.cs

@@ -71,7 +71,7 @@ internal static void Unknown(string key)
             internal const string AllowAdmin = "allowAdmin", SyncTimeout = "syncTimeout",
                                 ServiceName = "serviceName", ClientName = "name", KeepAlive = "keepAlive",
                         Version = "version", ConnectTimeout = "connectTimeout", Password = "password",
-                        TieBreaker = "tiebreaker", WriteBuffer = "writeBuffer", Ssl = "ssl", SslHost = "sslHost",
+                        TieBreaker = "tiebreaker", WriteBuffer = "writeBuffer", Ssl = "ssl", SslHost = "sslHost", HighPrioritySocketThreads = "highPriorityThreads",
                         ConfigChannel = "configChannel", AbortOnConnectFail = "abortConnect", ResolveDns = "resolveDns",
                         ChannelPrefix = "channelPrefix", Proxy = "proxy", ConnectRetry = "connectRetry",
                         ConfigCheckSeconds = "configCheckSeconds", ResponseTimeout = "responseTimeout", DefaultDatabase = "defaultDatabase";
@@ -80,7 +80,7 @@ internal static void Unknown(string key)
                 AllowAdmin, SyncTimeout,
                 ServiceName, ClientName, KeepAlive,
                 Version, ConnectTimeout, Password,
-                TieBreaker, WriteBuffer, Ssl, SslHost,
+                TieBreaker, WriteBuffer, Ssl, SslHost, HighPrioritySocketThreads,
                 ConfigChannel, AbortOnConnectFail, ResolveDns,
                 ChannelPrefix, Proxy, ConnectRetry,
                 ConfigCheckSeconds, DefaultDatabase,
@@ -100,7 +100,7 @@ public static string TryNormalize(string value)
 
         private readonly EndPointCollection endpoints = new EndPointCollection();
 
-        private bool? allowAdmin, abortOnConnectFail, resolveDns, ssl;
+        private bool? allowAdmin, abortOnConnectFail, highPrioritySocketThreads, resolveDns, ssl;
 
         private string clientName, serviceName, password, tieBreaker, sslHost, configChannel;
 
@@ -210,6 +210,11 @@ public CommandMap CommandMap
         /// </summary>
         public EndPointCollection EndPoints { get { return endpoints; } }
 
+        /// <summary>
+        /// Use ThreadPriority.AboveNormal for SocketManager reader and writer threads (true by default). If false, ThreadPriority.Normal will be used.
+        /// </summary>
+        public bool HighPrioritySocketThreads { get { return highPrioritySocketThreads ?? true; } set { highPrioritySocketThreads = value; } }
+
         /// <summary>
         /// Specifies the time in seconds at which connections should be pinged to ensure validity
         /// </summary>
@@ -322,6 +327,7 @@ public ConfigurationOptions Clone()
                 writeBuffer = writeBuffer,
                 ssl = ssl,
                 sslHost = sslHost,
+                highPrioritySocketThreads = highPrioritySocketThreads,
                 configChannel = configChannel,
                 abortOnConnectFail = abortOnConnectFail,
                 resolveDns = resolveDns,
@@ -372,6 +378,7 @@ public override string ToString()
             Append(sb, OptionKeys.WriteBuffer, writeBuffer);
             Append(sb, OptionKeys.Ssl, ssl);
             Append(sb, OptionKeys.SslHost, sslHost); 
+            Append(sb, OptionKeys.HighPrioritySocketThreads, highPrioritySocketThreads);
             Append(sb, OptionKeys.ConfigChannel, configChannel);
             Append(sb, OptionKeys.AbortOnConnectFail, abortOnConnectFail);
             Append(sb, OptionKeys.ResolveDns, resolveDns);
@@ -471,7 +478,7 @@ void Clear()
         {
             clientName = serviceName = password = tieBreaker = sslHost = configChannel = null;
             keepAlive = syncTimeout = connectTimeout = writeBuffer = connectRetry = configCheckSeconds = defaultDatabase = null;
-            allowAdmin = abortOnConnectFail = resolveDns = ssl = null;
+            allowAdmin = abortOnConnectFail = highPrioritySocketThreads = resolveDns = ssl = null;
             defaultVersion = null;
             endpoints.Clear();
             commandMap = null;
@@ -567,6 +574,9 @@ private void DoParse(string configuration, bool ignoreUnknown)
                         case OptionKeys.SslHost:
                             SslHost = value;
                             break;
+                        case OptionKeys.HighPrioritySocketThreads:
+                            HighPrioritySocketThreads = OptionKeys.ParseBoolean(key, value);
+                            break;
                         case OptionKeys.WriteBuffer:
                             WriteBuffer = OptionKeys.ParseInt32(key, value);
                             break;

StackExchange.Redis/StackExchange/Redis/ConnectionMultiplexer.ReaderWriter.cs

@@ -10,7 +10,7 @@ partial class ConnectionMultiplexer
         partial void OnCreateReaderWriter(ConfigurationOptions configuration)
         {
             this.ownsSocketManager = configuration.SocketManager == null;
-            this.socketManager = configuration.SocketManager ?? new SocketManager(ClientName);
+            this.socketManager = configuration.SocketManager ?? new SocketManager(ClientName, configuration.HighPrioritySocketThreads);
         }
 
         partial void OnCloseReaderWriter()

StackExchange.Redis/StackExchange/Redis/SocketManager.Poll.cs

@@ -400,7 +400,7 @@ private void StartReader()
             var thread = new Thread(read, 32 * 1024); // don't need a huge stack
             thread.Name = name + ":Read";
             thread.IsBackground = true;
-            thread.Priority = ThreadPriority.AboveNormal; // time critical
+            thread.Priority = useHighPrioritySocketThreads ? ThreadPriority.AboveNormal : ThreadPriority.Normal; 
             thread.Start(this);
         }
         [StructLayout(LayoutKind.Sequential)]

StackExchange.Redis/StackExchange/Redis/SocketManager.cs

@@ -80,19 +80,21 @@ public sealed partial class SocketManager : IDisposable
         private readonly Queue<PhysicalBridge> writeQueue = new Queue<PhysicalBridge>();
 
         bool isDisposed;
+        private bool useHighPrioritySocketThreads = true;
 
         /// <summary>
         /// Creates a new (optionally named) SocketManager instance
         /// </summary>
-        public SocketManager(string name = null)
+        public SocketManager(string name = null, bool useHighPrioritySocketThreads = true)
         {
             if (string.IsNullOrWhiteSpace(name)) name = GetType().Name;
             this.name = name;
+            this.useHighPrioritySocketThreads = useHighPrioritySocketThreads;
 
             // we need a dedicated writer, because when under heavy ambient load
             // (a busy asp.net site, for example), workers are not reliable enough
             Thread dedicatedWriter = new Thread(writeAllQueues, 32 * 1024); // don't need a huge stack;
-            dedicatedWriter.Priority = ThreadPriority.AboveNormal; // time critical
+            dedicatedWriter.Priority = useHighPrioritySocketThreads ? ThreadPriority.AboveNormal : ThreadPriority.Normal; 
             dedicatedWriter.Name = name + ":Write";
             dedicatedWriter.IsBackground = true; // should not keep process alive
             dedicatedWriter.Start(this); // will self-exit when disposed