Chris Collins wrote:
a couple of years back we did a lot of experimentation between sun's vm
and jrocket. We had initially assumed that jrocket was going to scream
since thats what the press were saying. In short, what we discovered
was that certain jdk library usage was a little bit faster with jrocket,
but for core vm performance such as synchronization, primitive
operations the sun vm out performed. We were not taking account of
startup time, just raw code execution. As I said, this was a couple of
years back so things may of changed.
C
I run JRockit as its what some of our key customers use, and we need to
test things. One lovely feature is tests time out before the stack runs
out on a recursive operation; clearly different stack management at
work. Another: no PermGenHeapSpace to fiddle with.
* I have to turn debug logging of in hadoop test runs, or there are
problems.
* It uses short pointers (32 bits long) for near memory on a 64 bit JVM.
So your memory footprint on sub-4GB VM images is better. Java7 promises
this, and with the merger, who knows what we will see. This is
unimportant on 32-bit boxes
* debug single stepping doesnt work. That's ok, I use functional tests
instead :)
I havent looked at outright performance.
/
