具有基于任务的异步模式的UDP侦听器

Question

I am messing around with a UDP listener and the TAP.

I have a class that is responsible for listening for incoming UDP and that can be started and stopped. The Start() method simply calls the following method

    private async void Listen()
    {
        var resp = await _udpClient.ReceiveAsync().ConfigureAwait(continueOnCapturedContext: false);

        var eventHandler = PacketReceived;
        if (eventHandler != null)
            eventHandler(this, new UdpPacketReceivedEventArgs(resp));

        if (_running)
            Listen();
    }

Is this correct? I am a bit worried that I might exhaust the thread pool, because the thread is being kept alive by spawning a new Listen() call.

Answer 1

Is this correct? I am a bit worried that I might exhaust the thread pool, because the thread is being kept alive by spawning a new Listen() call.

Yes, it's totally correct, this operation is not CPU bound, it's IO bound. So, there are no threads in thread pool at all that are blocked waiting for the operation to complete.

There is a thread waiting for network requests to complete, but it is shared between all network requests (like UI thread). It's called the IO completion port thread on Windows. When the network request completes, an interrupt handler in the operating system adds a job to a queue for the IO completion port. To perform 1000 network requests, the requests are all started, and as the responses arrive, they are processed in turn by the single IO completion port.