[fedora-java] Drop GCJ AOT bits for F11?

[Mark Wielaard]

On Thu, 2008-11-20 at 14:49 -0500, Andrew Overholt wrote:
> * Andrew Haley <aph at redhat.com> [2008-11-20 12:00]:
> > Sure, the number of users is low, but on lower-performance boxes the
> > penalty of not having gcj and gcj-compiled packages available is quite
> > severe.
> 
> Do we have numbers on this?  I know you are correct but having hard
> numbers would be nice.

I only have anecdotal evidence (I did these experiments a long time
ago). Running eclipse fully interpreted, through for example jamvm
(sadly not packaged for Fedora yet), is on the order of 4 to 8 times as
slow as running eclipse interpreted with gij and aot-compiled core class
libraries. And the jamvm interpreter is faster than the standard
interpreter that comes with hotspot.

Comparing gij on a pure-bytecode program versus a the same compiled aot
with gcj doesn't directly give you the correct (hard) numbers though.
Since gij will at least use the aot compiled core-library (so at least
things like your String operations and HashMaps, etc are optimized).

I believe Andrew Hughes (CCed) has a zero-on-x86 install. So he might be
able to give a real number of how much slower zero-interpreted against
full hotspot and/or a fully gcj native compiled program is.

Cheers,

Mark