提高::写了一段时间后async_write失败 [英] boost::async_write fails after writing for some time

问题描述

我有一个非常奇特的问题。我写了写，它从第三方接收到连接的客户端数据的服务器。服务器写入到客户端（S）的罚款了一段时间，但经过一段时间，无论是async_write失败或写永不再来。对于我的程序，如果async_write永远不会返回，再没有后续的写操作将发生，直到一切都打击了我的服务器将排队从第三方接收数据。

I am having a very peculiar problem. I have written a server that writes data that it receives from a third party to connected clients. The server writes to the client(s) fine for a while, but after a while, async_write either fails or a write never returns. For my program, if an async_write never returns, then no subsequent writes will take place, and my server will queue up the data it receives from the third party until everything blows up.

我已经包含下面我code：

I have included my code below:

void ClientPartitionServer::HandleSignal(const CommonSessionMessage& message, int transferSize) {
  boost::lock_guard<boost::mutex> lock(m_mutex);
  if(m_clientSockets.size() != 0) {
    TransferToQueueBuffer(message.GetData(), transferSize);
  }
  if(m_writeCompleteFlag) {
    // TransferToWriteBuffer();
    for(vector<boost::asio::ip::tcp::socket*>::const_iterator i = m_clientSockets.begin(); i != m_clientSockets.end(); ++i) {
      WriteToClient(*i);
    }
  }
}

void ClientPartitionServer::WriteToClient(boost::asio::ip::tcp::socket* clientSocket) {
  m_writeCompleteFlag = false;
  cout << "Iniating write: " << m_identifier << endl;
  boost::asio::async_write(
    *clientSocket,
    boost::asio::buffer(m_queueBuffer.get(), m_queueBufferSize),
    boost::bind(
      &ClientPartitionServer::HandleWrite, this,
      boost::asio::placeholders::error,
      boost::asio::placeholders::bytes_transferred
  ));
}

void ClientPartitionServer::HandleWrite(const boost::system::error_code& ec, size_t bytes_transferred) {
  boost::lock_guard<boost::mutex> lock(m_mutex);
  if(ec != 0) {
    cerr << "Error writing to client: " << ec.message() << " " << m_identifier << endl;
    // return;
    cout << "HandleWrite Error" << endl;
    exit(0);
  }
  cout << "Write complete: " << m_identifier << endl;
  m_writeCompleteFlag = true;
  m_queueBuffer.reset();
  m_queueBufferSize = 0;
}

任何帮助将是AP preciated。

Any help would be appreciated.

感谢您。

推荐答案

在没有看到所有的code这很难说，但它是一个红旗，我认为你持有的互斥体在多个（甚至一） WriteToClient 调用。典型地保持任何种类的整个I / O（甚至异步你有在这里）一个锁充其量坏的性能和在最坏情况下为负载下怪异死锁的配方。如果异步写入完成内联，你会得到所谓的回 HandleWrite 在同一个线程/调用堆栈，例如，会发生什么？

Without seeing all the code it's hard to say, but it's a red flag to me that you hold the mutex across multiple (or even one) WriteToClient calls. Typically holding a lock of any kind across I/O (even async as you have here) is at best bad for performance and at worst a recipe for weird deadlocks under load. What happens if the async write completes inline and you get called back on HandleWrite in the same thread/callstack, for instance?

我会尝试重构这个使锁期间写调用释放。

I would try to refactor this so that the lock is released during the write calls.

无论解决原来是更一般的建议是：

Whatever the solution turns out to be, more general advice:

• 请不要跨越我锁定/ O的


• 添加一些诊断输出 - 什么
  线程调用每个处理程序，并在
  什么顺序？


• 尝试调试，一旦你打
  静态。应该可以
  从结果诊断死锁
  流程状态。

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