Re: Java program TGTRLS

David Gibbs skrev den 14-08-2007 15:43:

2. If you are running OS400 V5R2 or higher, attaching native code to
java classes & jar's is no longer recommended. Using the JIT compiler
is (apparently) more efficient and has better performance. To this, set
the java.compiler system property to 'jitc'.

I did some performance analysis on an image processing program I wrote, which needed optimization. It made a smoothed and scaled jpeg of the images stored in a set of tiff-files, and was CPU-bound.

Basically I found that the JITC compiler was 30% faster than opt40 for a large dataset even if the jitting took quite a performance hit at the beginning.

Note that this also means that the default jitc_de is less efficient than jitc.

The above was under V5R3.

I also checked the 32-bit 1.6 JVM, and the performance was essentially the same.