Reduced performance of xml serialization when TM enabled

Hi

As the title suggests, we are experiencing significantly reduced performance of xml serialization when TM is enabled. This is true even though when Isolator is not used in any of the tests, yes in fact even when no TM assemblies are referenced from the projects involved.

Simple example to prove the point:

using System;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Xml.Serialization;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace TypeMockPerformanceProblem
{
    [TestClass]
    public class UnitTest1
    {
        private static readonly XmlSerializer Serializer = new XmlSerializer(typeof(A));

        [TestMethod]
        public void TestMethod1()
        {
            var stopwatch = new Stopwatch();
            stopwatch.Start();
            var stream = new MemoryStream();
            Serializer.Serialize(stream, new A { Prop1 = "Shalom aleichem", Prop2 = "As-Salāmu `Alaykum" });
            stream.Seek(0, SeekOrigin.Begin);
            var a = (A)Serializer.Deserialize(stream);
            stopwatch.Stop();
            Console.WriteLine(string.Format(CultureInfo.InvariantCulture, "Creating serializer, serializing and deserializing: {0}", stopwatch.Elapsed));
        }
    }

    public class A
    {
        public string Prop1 { get; set; }
        public string Prop2 { get; set; }
    }
}

Run this with and without TM enabled and you will notice that the performance hit is approx 100%. This is very simplified example and the effect can of course be much bigger depending on the usage of xml serialization. In some extreme cases we have seen a couple of seconds turn into minutes(!).

The total impact of this phenomenon on the performance of our ~15K test harness is not known but we have good reason to think it is enourmous (to be conservative ;-)).

Question: Is this something you guys at TM are aware of and if so do you have plans to do something about it? Is it possible without rebuilding the whole thing (I am guessing this is an unwanted consequence of hooking into the profiling interface)? I am really keen to know the answer to these questions since we are now embarking on a quest to seriously speed up our test runs. One of the options on the table is of course to get rid of TM all together, and you wouldn't want that now would you? ;-)

Regards
Martin