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c#.netconsole-applicationautoresetevent

Why AutoResetEvent WaitOne waits differently on my PC?

I made a small funktion at a console app (.net 4.5.2) to check the exactness of the timeout at the AutoResetEvent.WaitOne funktion. On my laptop the waited time is almost exact the timeout at WaitOne (right picture). On every other system I had run this test, the timeout is mutch higher (left picture). I tried to update .net but without any change.

Is this different behavior related to a special hardware (Lenovo p52) of me, or I am using visual studio?

private static void WaitTest()
{
    try
    {
        using (var lResetEvent = new AutoResetEvent(false))
        {
            _stopwatch.Restart();
            lResetEvent.WaitOne(1);
            var l1Ms = _stopwatch.ElapsedMilliseconds;
            _stopwatch.Restart();
            lResetEvent.WaitOne(10);
            var l10Ms = _stopwatch.ElapsedMilliseconds;
            _stopwatch.Restart();
            lResetEvent.WaitOne(20);
            var l20Ms = _stopwatch.ElapsedMilliseconds;

            Console.WriteLine($"-----------------------------------------------------------");
            Console.WriteLine($" 1ms WaitTest: {l1Ms:D2}ms");
            Console.WriteLine($"10ms WaitTest: {l10Ms:D2}ms");
            Console.WriteLine($"20ms WaitTest: {l20Ms:D2}ms");
            Console.WriteLine($"-----------------------------------------------------------");
        }
    }
    catch (Exception lEx)
    {
        Console.WriteLine(lEx.ToStringEx());
    }
}

enter image description here

Solution

  • If you're referring to the different delay times, you might want to google timeBeginPeriod for some background information. – 500 - Internal Server Error

    leads me her: how to set timer resolution from C# to 1 ms?

    This is doing the job now:

     using (new TimePeriod(1))
    lResetEvent.WaitOne(WaitTime);

    The timer resolution seems not to effect the AutoResetEvent. Its alwaysaroud 15ms:

            [DllImport("kernel32.dll", SetLastError = true)]
    static extern bool GetSystemTimeAdjustment(out long lpTimeAdjustment, out long lpTimeIncrement, out bool lpTimeAdjustmentDisabled);