[Mono-bugs] [Bug 630759] [sgen] is slower than boehm for value types

[bugzilla_noreply at novell.com]

http://bugzilla.novell.com/show_bug.cgi?id=630759

http://bugzilla.novell.com/show_bug.cgi?id=630759#c1


--- Comment #1 from Mark Probst <mprobst at novell.com> 2010-08-12 16:18:13 UTC ---
The problem here is that we don't have smart handling of indirect ref stores. 
We always invoke the write barrier for them because the store might be to the
major heap.  In this case the indirect store is to the stack, however, which
doesn't need a write barrier.

Here is a simpler example where the difference is even more pronounced:


using System;
using System.Diagnostics;

public sealed class Program
{
    struct S
    {
        Program p;

        public S (Program p)
        {
            this.p = p;
        }
    }

    public static void Main()
    {
        Stopwatch sw;

        Program p = new Program ();

        sw = Stopwatch.StartNew();
        for (int nn = 0; nn < 300000000; ++nn) {
            S s = new S (p);
        }

        Console.WriteLine(sw.Elapsed + "\tM");
    }
}

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