Perry Stathopoulos

If you are running benchmarks with perfmon in Windows 2008 64-bit you can no longer user the ASP.NET and ASP.NET Application of perfmon is your application is in 32-bit mode.

As a better alternative anyway, is to use the new ServiceModel perfmon. You need to add the diagnostics section in the web.config like this:

<system.serviceModel>
    <diagnostics performanceCounters="All" />
</system.serviceModel>  

Then you will have access to metrics for each operation(method) in each endpoint in the ServiceModel* categories of perfmon. Really nice!

For more details:

http://blogs.msdn.com/wenlong/archive/2007/09/07/how-to-use-performance-counters-to-diagnose-performance-of-wcf-applications.aspx