[英]Does async/await affects tcp server performance?
我在C#5.0中創建一個Tcp服務器,我在調用tcpListener.AcceptTcpClientAsync
和networkStream.ReadAsync
時使用了await關鍵字
但是,當我使用Process Explorer檢查我的服務器的CPU使用率時,我得到以下結果:
Tcp Sync版本: CPU使用率為10%
Tcp異步版本: 30%的CPU使用率一半的使用是內核使用。
此外,我通過在網絡流的外觀中添加計數器來測量我接收數據的時間,並且異步版本循環120,000次,而同步版本循環2,500,000次。
在收到的消息/秒中,當從3個不同的客戶端接收消息時,異步版本比同步版本慢15%。
為什么Async Version比Sync版本使用更多的CPU?
這是因為async / await關鍵字?
Async Tcp服務器比其同步速度慢嗎?這是正常的嗎?
編輯:這是異步tcp服務器代碼的示例
public class AsyncTcpListener : ITcpListener
{
private readonly ServerEndpoint _serverEndPoint; // Custom class to store IpAddress and Port
public bool IsRunning { get; private set; }
private readonly List<AsyncTcpClientConnection> _tcpClientConnections = new List<AsyncTcpClientConnection>();
private TcpListener _tcpListener;
public AsyncTcpMetricListener()
{
_serverEndPoint = GetServerEndpoint();
}
public async void Start()
{
IsRunning = true;
RunTcpListener();
}
private void MessageArrived(byte[] buffer)
{
// Deserialize
}
private void RunTcpListener(){
_tcpListener = null;
try
{
_tcpListener = new TcpListener(_serverEndPoint.IpAddress, _serverEndPoint.Port);
_tcpListener.Start();
while (true)
{
var tcpClient = await _tcpListener.AcceptTcpClientAsync().ConfigureAwait(false);
var asyncTcpClientConnection = new AsyncTcpClientConnection(tcpClient, MessageArrived);
_tcpClientConnections.Add(asyncTcpClientConnection);
}
}
finally
{
if (_tcpListener != null)
_tcpListener.Stop();
IsRunning = false;
}
}
public void Stop()
{
IsRunning = false;
_tcpListener.Stop();
_tcpClientConnections.ForEach(c => c.Close());
}
}
對於每個新客戶端,我們創建一個新的AsyncTcpConnection
public class AsyncTcpClientConnection
{
private readonly Action<byte[]> _messageArrived;
private readonly TcpClient _tcpClient;
public AsyncTcpClientConnection(TcpClient tcpClient, Action<byte[]> messageArrived)
{
_messageArrived = messageArrived;
_tcpClient = tcpClient;
ReceiveDataFromClientAsync(_tcpClient);
}
private async void ReceiveDataFromClientAsync(TcpClient tcpClient)
{
var readBuffer = new byte[2048];
// PacketProtocol class comes from http://blog.stephencleary.com/2009/04/sample-code-length-prefix-message.html
var packetProtocol = new PacketProtocol(2048);
packetProtocol.MessageArrived += _messageArrived;
try
{
using (tcpClient)
using (var networkStream = tcpClient.GetStream())
{
int readSize;
while ((readSize = await networkStream.ReadAsync(readBuffer, 0, readBuffer.Length).ConfigureAwait(false)) != 0)
{
packetProtocol.DataReceived(readBuffer, readSize);
}
}
}
catch (Exception ex)
{
// log
}
}
public void Close()
{
_tcpClient.Close();
}
}
EDIT2:同步服務器
public class TcpListener : ITcpListener
{
private readonly ObserverEndpoint _serverEndPoint;
private readonly List<TcpClientConnection> _tcpClientConnections = new List<TcpClientConnection>();
private Thread _listeningThread;
private TcpListener _tcpListener;
public bool IsRunning { get; private set; }
public TcpMetricListener()
{
_serverEndPoint = GetServerEndpoint();
}
public void Start()
{
IsRunning = true;
_listeningThread = BackgroundThread.Start(RunTcpListener);
}
public void Stop()
{
IsRunning = false;
_tcpListener.Stop();
_listeningThread.Join();
_tcpClientConnections.ForEach(c => c.Close());
}
private void MessageArrived(byte[] buffer)
{
// Deserialize
}
private void RunTcpListener()
{
_tcpListener = null;
try
{
_tcpListener = new TcpListener(_serverEndPoint.IpAddress, _serverEndPoint.Port);
_tcpListener.Start();
while (true)
{
var tcpClient = _tcpListener.AcceptTcpClient();
_tcpClientConnections.Add(new TcpClientConnection(tcpClient, MessageArrived));
}
}
finally
{
if (_tcpListener != null)
_tcpListener.Stop();
IsRunning = false;
}
}
}
和連接
public class TcpClientConnection
{
private readonly Action<byte[]> _messageArrived;
private readonly TcpClient _tcpClient;
private readonly Task _task;
public TcpClientConnection(TcpClient tcpClient, Action<byte[]> messageArrived)
{
_messageArrived = messageArrived;
_tcpClient = tcpClient;
_task = Task.Factory.StartNew(() => ReceiveDataFromClient(_tcpClient), TaskCreationOptions.LongRunning);
}
private void ReceiveDataFromClient(TcpClient tcpClient)
{
var readBuffer = new byte[2048];
var packetProtocol = new PacketProtocol(2048);
packetProtocol.MessageArrived += _messageArrived;
using (tcpClient)
using (var networkStream = tcpClient.GetStream())
{
int readSize;
while ((readSize = networkStream.Read(readBuffer, 0, readBuffer.Length)) != 0)
{
packetProtocol.DataReceived(readBuffer, readSize);
}
}
}
public void Close()
{
_tcpClient.Close();
_task.Wait();
}
}
我也有async
問題,這些是我的發現: https : //stackoverflow.com/a/22222578/307976
另外,我有使用異步TCP客戶端/服務器async
例如這里擴展良好。
嘗試使用ReceiveInt32Async
和ReceiveDataAsync
的以下實現來直接接收長度為前綴的消息,而不是使用tcpClient.GetStream
和networkStream.ReadAsync
:
public static class SocketsExt
{
static public async Task<Int32> ReceiveInt32Async(
this TcpClient tcpClient)
{
var data = new byte[sizeof(Int32)];
await tcpClient.ReceiveDataAsync(data).ConfigureAwait(false);
return BitConverter.ToInt32(data, 0);
}
static public Task ReceiveDataAsync(
this TcpClient tcpClient,
byte[] buffer)
{
return Task.Factory.FromAsync(
(asyncCallback, state) =>
tcpClient.Client.BeginReceive(buffer, 0, buffer.Length,
SocketFlags.None, asyncCallback, state),
(asyncResult) =>
tcpClient.Client.EndReceive(asyncResult),
null);
}
}
看看這是否有任何改進。 另外,我還建議將ReceiveDataFromClientAsync
為async Task
方法,並將其返回的Task
存儲在AsyncTcpClientConnection
(用於狀態和錯誤跟蹤)。
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