wood burning stoves 2.0*
The moose likes Performance and the fly likes JIT compiler Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Performance
Bookmark "JIT compiler" Watch "JIT compiler" New topic
Author

JIT compiler

Balki Dhar
Greenhorn

Joined: Dec 15, 2005
Posts: 18
Hi
I heard that JIT complier increases the performance. How to do that in realtime environment. We are using Websphere application server running on OS/390 Platform.
Balki
shailesh sonavadekar
Ranch Hand

Joined: Oct 12, 2000
Posts: 1874
You are correct to certain extent. JIT ( Just In Time)Compilers are not so fast also. JIT compilers can speed up the program execution 7 to 10 times over interpreting. In this case , vm compiles the bytecode to native machine code the first time the method is invoked. ( the method is compiled " just in time " for it's first use by vm. the native machine code is picked by vm next time the same method is invoked. thus , you can get faster execution.
But , there are trade-offs. sometimes rather many a times , the footprint of the compiled code is more than that of interpreted code. it may also happen that the vm spends a lot of time with just in time compiling everything, vm doesn't have time to do a thorough optimization of the code.
thus , jit has its own trade - off. I hope that this is helpful to you. Regarding websphere app. server on os/390 , i don't have any idea.
one for thing , dbalki. As the official naming policy of this forum , the user has to register hmself/ herself with proper first name & last name. Thus , I request you to register yourself with name as per naming policy & participate in the discussion forum.
SHAILESH.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: JIT compiler