CODEWITHSUNDEEP
c#udp
Skycoder
Skycoder

Reputation: 3

C# UdpClient.Send get's slower and slower

I want to send a bunch of data with low latency to another device using UDP.

This is a short snippet that reproduces the problem:

private void Form1_Shown(object sender, EventArgs e)
    {
        UdpClient udpClient = new UdpClient(9000);
        IPEndPoint endPoint = new IPEndPoint(IPAddress.Broadcast, 7000);

        new Thread(() =>
        {
            Stopwatch stopwatch = new Stopwatch();
            byte[] buffer = new byte[1922];
            while (true)
            {          
                stopwatch.Start();
                udpClient.Send(buffer, buffer.Length, endPoint);
                stopwatch.Stop();
                Console.WriteLine("Sending took " + stopwatch.ElapsedMilliseconds + "ms"); // stopwatch.ElapsedMilliseconds gets higher and higher
                Thread.Sleep(10);
            }
        }).Start();
    }

The buffer has the same size everytime (in the loop) and the packets are sent every 10 ms...normally.

But approx. every 300ms it takes 1 additional millisecond to send so after a short time it takes already 1 minute to send a packet.

What is the problem there and how do I fix it?

Upvotes: 0

Views: 442

Answers (1)

khargoosh
khargoosh

Reputation: 1520

The problem is in your measurement: you're not resetting your stopwatch anywhere. Instead of calling the stopwatch.Start() method, call the Restart() method instead.

Stopwatch Class (MSDN)

Restart() : Stops time interval measurement, resets the elapsed time to zero, and starts measuring elapsed time.

while (true)
{          
    stopwatch.Restart();
    udpClient.Send(buffer, buffer.Length, endPoint);
    stopwatch.Stop();
    Console.WriteLine("Sending took " + stopwatch.ElapsedMilliseconds + "ms"); 
    Thread.Sleep(10);
}

Upvotes: 2

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