C# Method-Call faster than just code

问题

i wanted to test how much time is lost by putting code into methods instead of just calling it.

To my surprise, the Method-Calls are faster and i ask myself: why?

This is the code: The HObjects are part of the image processing library "Halcon" and are very commonly used with "out" in method calls, so dont worry about the horrible look ;-)

    static void Main(string[] args)
    {
        int runs = 900000;
        HObject hob1;
        HObject hob2;
        HObject hob3;
        HObject hob4;
        HObject hob5;
        HObject hob6;

        DateTime t1 = DateTime.Now;

        for ( int i = 0; i < runs; i++ )
        {
            doItMethod(out hob1, out hob2, out hob3, out hob4, out hob5, out hob6);
        }

        TimeSpan ts1 = TimeSpan.FromTicks(DateTime.Now.Ticks - t1.Ticks);

        DateTime t2 = DateTime.Now;

        for ( int i = 0; i < runs; i++ )
        {
            HOperatorSet.GenEmptyObj(out hob1);
            HOperatorSet.GenEmptyObj(out hob2);
            HOperatorSet.GenEmptyObj(out hob3);
            HOperatorSet.GenEmptyObj(out hob4);
            HOperatorSet.GenEmptyObj(out hob5);
            HOperatorSet.GenEmptyObj(out hob6);

            hob1.Dispose();
            hob2.Dispose();
            hob3.Dispose();
            hob4.Dispose();
            hob5.Dispose();
            hob6.Dispose();
        }

        TimeSpan ts2 = TimeSpan.FromTicks(DateTime.Now.Ticks - t2.Ticks);

        Console.WriteLine("Zeitspanne Methodenaufruf : " + ts1.TotalMilliseconds.ToString());
        Console.WriteLine("Zeitspanne direkter Aufruf: " + ts2.TotalMilliseconds.ToString());

        Console.ReadKey();
    }


    static void doItMethod(out HObject hobOut1, out HObject hobOut2, out HObject hobOut3, out HObject hobOut4, out HObject hobOut5, out HObject hobOut6)
    {
        HOperatorSet.GenEmptyObj(out hobOut1);
        HOperatorSet.GenEmptyObj(out hobOut2);
        HOperatorSet.GenEmptyObj(out hobOut3);
        HOperatorSet.GenEmptyObj(out hobOut4);
        HOperatorSet.GenEmptyObj(out hobOut5);
        HOperatorSet.GenEmptyObj(out hobOut6);

        hobOut1.Dispose();
        hobOut2.Dispose();
        hobOut3.Dispose();
        hobOut4.Dispose();
        hobOut5.Dispose();
        hobOut6.Dispose();
    }

回答1:

You should use Stopwatch

 //add using System.Diagnostics;

 public static void Main()
    {
        int runs = 900000;
        HObject hob1;
        HObject hob2;
        HObject hob3;
        HObject hob4;
        HObject hob5;
        HObject hob6;

        Stopwatch t1 = new Stopwatch();

        t1.Start();

        for ( int i = 0; i < runs; i++ )
        {
            doItMethod(out hob1, out hob2, out hob3, out hob4, out hob5, out hob6);
        }

        t1.Stop();


        Stopwatch t2 = new Stopwatch();
        t2.Start();

        for ( int i = 0; i < runs; i++ )
        {
            HOperatorSet.GenEmptyObj(out hob1);
            HOperatorSet.GenEmptyObj(out hob2);
            HOperatorSet.GenEmptyObj(out hob3);
            HOperatorSet.GenEmptyObj(out hob4);
            HOperatorSet.GenEmptyObj(out hob5);
            HOperatorSet.GenEmptyObj(out hob6);

            hob1.Dispose();
            hob2.Dispose();
            hob3.Dispose();
            hob4.Dispose();
            hob5.Dispose();
            hob6.Dispose();
        }
        t2.Stop();



        Console.WriteLine("Zeitspanne Methodenaufruf : " + t1.ElapsedMilliseconds);
        Console.WriteLine("Zeitspanne direkter Aufruf: " + t2.ElapsedMilliseconds);

        Console.ReadKey();
    }

回答2:

I got right results using Stopwatch:

Method: 00:00:04.5573170
Code: 00:00:04.5539918



static void Main(string[] args)
    {
        int runs = 1000;
        HObject hob1;
        HObject hob2;
        HObject hob3;
        HObject hob4;
        HObject hob5;
        HObject hob6;

        Stopwatch sw = new Stopwatch();
        sw.Start();

        for (int i = 0; i < runs; i++)
        {
            doItMethod(out hob1, out hob2, out hob3, out hob4, out hob5, out hob6);
        }

        sw.Stop();
        Console.WriteLine(sw.Elapsed);

        sw = Stopwatch.StartNew();

        for (int i = 0; i < runs; i++)
        {
            HOperatorSet.GenEmptyObj(out hob1);
            HOperatorSet.GenEmptyObj(out hob2);
            HOperatorSet.GenEmptyObj(out hob3);
            HOperatorSet.GenEmptyObj(out hob4);
            HOperatorSet.GenEmptyObj(out hob5);
            HOperatorSet.GenEmptyObj(out hob6);

            hob1.Dispose();
            hob2.Dispose();
            hob3.Dispose();
            hob4.Dispose();
            hob5.Dispose();
            hob6.Dispose();
        }

        sw.Stop();
        Console.WriteLine(sw.Elapsed);

        Console.ReadKey();
    }

回答3:

Thanks people! I got my answer.

As Eugen Rieck suspected, it was a GC-Artifact.

Enforcing garbage collection makes the method-call version slower than direct code.

来源：https://stackoverflow.com/questions/12384586/c-sharp-method-call-faster-than-just-code