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I am running performance profile for a C# application on a virtual machine. The results shows a huge load of "JIT Compiler". When I dig further, it shows something called "Class Loader" as the only method getting called by JIT compiler.

What should I do to bring "JIT compiler" load down?

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JIT is the 'Just In Time' compiler, this essentially compiles your C# into executable code that can work on the current processor.

.Net comes with a utility called NGEN, this creates a native image of your C# code, that doesn't need to be JIT'ted. There are downsides to this however, have a read of this:


And finally here's a link to the MS info about NGEN:


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So this means JIT load most likely comes at the startup only?? or the first time a function gets executed? –  bsobaid Jul 16 '10 at 17:55
The JIT Load will come at startup, or dynamically loaded Assemblies. You'll also trigger it, in ASP.Net when using Control.LoadControl(). –  Russ C Jul 19 '10 at 8:01
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You could try using NGEN to pre-JIT your assemblies to native images. This will lessen Jitting overhead on application load:


You should run this tool on the machine where your assemblies are i.e. your virtual machine.

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