Question

I have a weird problem with the Windows Phone 7.1 API. Im trying to write an app to send touch-delta from the touch-screen to move a mouse-pointer on a desktop-pc. Im using UDP-sockets but I have some performance-issues.

The sending of udp-messages seem to freeze for 0.5-1.0 sec every ~0.5 seconds or so. Im not sending huge amounts of data and Im throttling it as well. My latest attempt to find whats causing it turned out a bit unexpected.

When having a separate thread with a while-loop that keeps sending random-data everything works smooth and fine. But when I start touching the screen of the WP7-mobile I start getting these weird hiccups. I have removed all listeners on touch-events for debugging purposes and Im not doing anything else in my app then sending this data on a UDP-socket. But why is it freezing up like this when I move my finger over the screen? It kind of makes it impossible to write an app like this.

I ve heard that touch-manipulation should be moved to a dedicated thread, is that included in the Beta2 refresh of WP7.1?

The code goes somewhat like this:

    new Thread(() =>
    {
        while (true)
        {
            _event.Reset();
            _socket.SendToAsync(_args);
            _event.WaitOne();
            Thread.Sleep(5);
        }
    }).Start();

The event-handle is set when SendToAsync is completed. So it keeps sending udp-data about every 5 ms. It works fine (I can receive in a steady and rapid rate) as long as I dont touch and drag my finger on the phone s screen. Then I start getting 1 sec freezings in regular intervals. Very strange since Im running the udp-firing on a separate thread. Is the CPU of the phone being overloaded in some way when its processing manipulation? Could that be causing the hiccups?

Update

I ve refrased and updated this question in another thread to make it a bit more clear:

Poor UDP performance with Windows Phone 7.1 (Mango)

Answer 1

Everything runs on the UI thread till you push it to another thread. Most of my event handlers look like this

ThreadPool.QueueUserWorkItem(state => /* do stuff */);

I have Mango b2 and it is true that some stuff has been moved off the UI thread but this is erratic and it s easy to do it yourself.

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