Pre-Jiting a ASP.NET website

Question

What does Pre-Jiting a ASP.NET website means.

Tulasi · Answer

have a look at this http://msdn.microsoft.com/hi-in/magazine/cc163808(en-us).aspx

Sam Hobbs · Answer

Pre-Jiting is a misuse of English. It is a contradiction; JIT is contradictory with pre-wahtever. Microsoft is using confusing terminology. I would not say anything if it were not Microsoft but since it is Microsoft I must explain that they don't make a lot of effort to avoid confusion. They call the MSDN forums social but there is not a single social forum in the MSDN forums. In Windows the Windows Explorer explores file systems not windows. There are other examples that I cannot think of at the moment.

Kunal Naik · Answer

Hi Pre-Jiting:- Managed Assemblies contain Intermediate Language (IL). The CLR JIT-compiles the IL into optimized CPU instructions. The JIT compilation will take a certain amount of time but this startup time can be improved by doing compilation at install time (pre-JITing) using NGEN.exe. This produces a native binary image for the application thereby eliminating the JIT overhead but at the expense of portability. When an NGEN-generated image is run in an incompatible environment the .NET framework automatically reverts to using JIT. Once NGEN is run against an assembly the resulting native image is placed into the Native Image Cache for use by all other .NET assemblies. A pre-JITed assembly is a persisted form of a JITed MSIL with a class/v-table layout. It is always worth checking performance before and after using this technique as it can actually have an adverse effect. If a pre-JITed assembly is not installed in the GAC (Global Assembly Cache)  then Fusion (the .NET technology used to locate and load .NET assemblies) needs to verify that the native image and the MSIL assembly have the same version to ensure that the cached native image relates to the current version of the code during binding. In order to do that the CLR needs to access pages in the MSIL assembly which can hurt cold startup time.

Tulasi · Answer

Hi Pre-compilation or pre-JITing is the creation of native code from MSIL on the client machine but instead of being generated at run time it is done as a separate isolated step.