我在C#5.0中创建一个Tcp服务器,我在调用 tcpListener.AcceptTcpClientAsync
和 networkStream.ReadAsync
时使用了await关键字
但是,当我使用Process Explorer检查我的服务器的CPU使用率时,我得到以下结果:
Tcp Sync版本: 10% CPU usage
Tcp异步版本: 30% CPU usage 一半的使用是内核使用 .
此外,我通过在网络流的外观中添加计数器来测量我接收数据的时间,并且异步版本循环120,000次,而同步版本循环2,500,000次 .
在收到的消息/秒中,当从3个不同的客户端接收消息时,异步版本比同步版本慢15% .
Why does the Async Version use a lot more CPU than the Sync version?
这是因为async / await关键字?
Is this normal that an Async Tcp server is slower than its sync counterpart?
EDIT: Here is an example of the async tcp server code
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());
}
}
对于每个新客户端,我们创建一个新的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: Synchronous server
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;
}
}
}
和连接
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();
}
}
2 回答
我也有
async
的问题,这些是我的发现:https://stackoverflow.com/a/22222578/307976此外,我有一个异步TCP服务器/客户端使用
async
示例here可以很好地扩展 .尝试使用
ReceiveInt32Async
和ReceiveDataAsync
的以下实现来直接接收长度为前缀的消息,而不是使用tcpClient.GetStream
和networkStream.ReadAsync
:看看这是否有任何改进 . 另外,我还建议将
ReceiveDataFromClientAsync
设为async Task
方法并将Task
存储在AsyncTcpClientConnection
内(用于状态和错误跟踪) .