iocp

问题 It's very hard to find detailed but simple description of worker and I/O threads in .NET What's clear to me regarding this topic (but may not be technically precise): Worker threads are threads that should employ CPU for their work; I/O threads (also called "completion port threads") should employ device drivers for their work and essentially "do nothing", only monitor the completion of non-CPU operations. What is not clear: Although method ThreadPool.GetAvailableThreads returns number of

问题 It's very hard to find detailed but simple description of worker and I/O threads in .NET What's clear to me regarding this topic (but may not be technically precise): Worker threads are threads that should employ CPU for their work; I/O threads (also called "completion port threads") should employ device drivers for their work and essentially "do nothing", only monitor the completion of non-CPU operations. What is not clear: Although method ThreadPool.GetAvailableThreads returns number of

问题 CreateIoCompletionPort() is used to associate a socket with a completion port. However, when this socket is closed, then I need to "un-associate" it from the completion port. How can I do that? 回答1: A handle that is associated with an I/O Completion Port is removed from the port when the handle is closed. In case of a network socket, the handle is closed by calling closesocket(). The documentation for CreateIoCompletionPort contains remarks on resource handling: The handle passed in the

问题 Let's say I have Windows 7 with one real network interface and few loopback interfaces. I have IOCP enabled server that accepts connections from clients. I'm trying to simulate as much as possible real client connections to the server. My client code simply establishes X amount of socket connections (note that client binds to a given interface): const Int32 remotePort = 12345; const Int32 MaxSockets = 60000; Socket[] s = new Socket[MaxSockets]; IPEndPoint bindEndpoint = new IPEndPoint

问题 I would like to create a IOCP application to received TCP data, Once received, I will have to processing the data and write out the bytes partially. Understand that WSASend with IOCP can do the job. But I am worrying whether WSASend to the queue and does GetQueuedCompletionStatus synchronizely?. For Example:- void processing_from_other_thread(...) { ... DWORD state = still_doing1; WSASend( ..,..,.., &state, .. ); DWORD state = still_doing2; WSASend( ..,..,.., &state, .. ); DWORD state = still

问题 Although I have read a lot about WSAsend (msdn), I still need some clarifications. Part of my code: int rc; rc=WSASend(Socket,....); if (rc==0) {....} else if ((rc == SOCKET_ERROR) && (WSA_IO_PENDING != (err = WSAGetLastError()))) { printf("WSASend failed with error: %d Socket(%d) \n", err,(pTmp1->Socket)); .... } There is said in msdn that WSAsend operation may sometimes completes immediately returning zero (it never happened during my test server ). So if this happens, the

问题 I'm using IOCP on UDP socket, and the UDP socket may be closed in another thread. So, how can I free Per Socket Context and Per I/O Context which associated with SOCKET safely? When I close the socket, there will still be un-completed I/O request in kernel queue. If I free context just when socket closed, the GetQueueCompletionStatus may failed. Now, my question is when to free context? 回答1: I use reference counting on all of my per socket and per I/O data structures. It makes this kind of

问题 I want to use a thread pool to both initiate/cancel overlapped read operations -- using ReadFile() and CancelIo() respectively -- as well as handling any completion port events when read operations complete. Any thread can initiate a read operation Any thread can handle a read-complete event Only the thread that initiated a read may cancel it (this is a CancelIo() limitation) I'm not sure how to implement this. One normally calls GetQueuedCompletionStatus() to wait on completion port events

问题 The .NET / .NET Core Thread Pool uses two different categories of threads internally: worker threads and I/O Completion Port (IOCP) threads. Both are just usual managed threads, but used for different purposes. Via different APIs (e.g. Task.Start or ThreadPool.QueueUserWorkItem ) I can start CPU-bound async operations on the worker threads (which shouldn't block, otherwise the Thread Pool would probably create additional worker threads). But what about performing I/O-bound asynchronous

问题 When I compile this code on a machine with Windows 7 Ultimate and .NET 4 installed, it works just fine but when I try it on one with Windows 8 RTM and .NET 4.5 installed, Complete event never fires. class Program { private static Socket _Socket = new Socket( AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); private static void Main(string[] args) { _Socket.Bind(new IPEndPoint(IPAddress.Any, 5012)); _Socket.Listen(100); var arguments = new SocketAsyncEventArgs(); arguments