Where is ngen.exe?

T ypically, methods in managed executables are just-in-time (JIT) compiled. The machine code generated by the JIT compiler is thrown away once the process running that executable exits; therefore, the method must be recompiled when the application is run again.

Surupa Biswas

MSDN Magazine May 2006

In the .NET Framework 2.0, NGen has been greatly improved and offers a number of compelling new features to make it easier and faster to deploy high-performance managed applications. This article introduces some of these new features and explains how and when you should use NGen to improve the performance of your apps.

Reid Wilkes

MSDN Magazine April 2005

Advanced performance question here.  Here's my scenario:

I have a database that contains thousands of XSLT documents.  One for each page of a website so these translate XML into HTML.  An ASP.NET web server (farm) loads the XSLT documents from the database and uses them to render HTML for each web request.

I've implemented the optimization of using XslCompiledTransform and caching it between database refreshed (every 30 minutes).  I'm looking to notch performance up further by pre-compiling the XSLT to DLLs with xsltc.exe.  This is supposed to eliminate all the Dynamic Method Invocations that XslCompiledTransform creates.

So, I have a separate server writing the XSLTs to files and running through them with xsltc.exe. Takes about 20 minutes but that's OK.  I then drop the DLLs onto each webserver.  Now I can just have the webserver dynamically load the DLLs on an as-needed basis.  Here's the code I'm using to load the assembly into XslCompiledTransform:

byte[] bytes = File.ReadAllBytes(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "XsltDlls\\" + fileName + ".dll"));
Assembly assembly = Assembly.Load(bytes);
Type type = assembly.GetType(fileName);
XslCompiledTransform compiledTransform = new XslCompiledTransform();
compiledTransform.Load(type);