Small web service benchmark

I am trying to develop a small application that checks how many requests per second my service can support, but I think I am doing something wrong. The service is in early stages of development, but I would like this test to be handy to check from time to time that I am not doing something that slows down performance. The problem is I can't get the webserver or database server to go 100% CPU.

I am using three different computers, one is a web server (WinSrv Standard 2008 x64 IIS7), another database (Win 2K, SQL Server 2005), and the last one is my computer (Win7 x64 Ultimate) where I will run the test. The computers are connected via an Ethernet network switch. The POST request is 9 bytes and the response will be 842 bytes.

The test runs multiple threads, and each thread has a loop while

, in each loop it creates an object WebRequest

, makes a call, increments the total counter and waits for 1 to 5 milliseconds, then it does it again:

static int counter = 0;

static void Main(string[] args)
{
    ServicePointManager.DefaultConnectionLimit = 250;

    Console.WriteLine("Ready. Press any key...");
    Console.ReadKey();
    Console.WriteLine("Running...");

    string localhost = "localhost";
    string linuxmono = "192.168.1.74";
    string server = "192.168.1.5:8080";

    DateTime start = DateTime.Now;

    Random r = new Random(DateTime.Now.Millisecond);
    for (int i = 0; i < 50; i++)
    {
        new Thread(new ParameterizedThreadStart(Test)).Start(server);
        Thread.Sleep(r.Next(1, 3));
    }

    Thread.Sleep(2000);

    while (true)
    {
        Console.WriteLine("Request per second :"
            + counter / DateTime.Now.Subtract(start).TotalSeconds);
        Thread.Sleep(3000);
    }
}

public static void Test(object ip)
{
    Guid guid = Guid.NewGuid();

    Random r = new Random(DateTime.Now.Millisecond);
    while (true)
    {
        String test = "<lalala/>";
        WebRequest req = WebRequest.Create("http://"
            + (string) ip + "/WebApp/" + guid.ToString()
            + "/Data/Tables=whatever");
        req.Method = "POST";
        req.ContentType = "application/xml";
        req.Credentials = new NetworkCredential("aaa", "aaa","domain");
        byte[] array = Encoding.UTF8.GetBytes(test);
        req.ContentLength = array.Length;
        using (Stream reqStream = req.GetRequestStream())
        {
            reqStream.Write(array, 0, array.Length);
            reqStream.Close();
        }

        using (Stream responseStream = req.GetResponse().GetResponseStream())
        {
            String response = new StreamReader(responseStream).ReadToEnd();
            if (response.Length != 842) Console.Write(" EEEE ");
        }

        Interlocked.Increment(ref counter);

        Thread.Sleep(r.Next(1,5));
    }
}

      

        
        
        
      

    

If I run the test, none of the computers are using excessive CPU usage. Let's say I get X requests per second, if I run the console app twice at the same moment, I get X / 2 requests per second in each of them ... but still the webserver is at 30% from CPU, database server at 25% ...

I tried deleting Thread.Sleep

in a loop, but it doesn't really matter.

I would like to put the machines at maximum to test how they can query per second they can provide. I guessed that I could do it this way ... but apparently I am missing something here ... What is the problem?

Sincerely.