Re: dacapo benchmarks

[Andrew Haley <aph at redhat dot com>]

Patrick Olinet writes:

 > I'm trying to run the dacapo benchmarks suite with gcj
 > (http://www.dacapobench.org).
 > 
 > * I've downloaded the dacapo-2006-10-MR2-xdeps.zip but I haven't been
 > able to compile the following benchmarks : bloat, jython, chart, fop,
 > pmd and xalan. It seems to be due to libraries missing in the
 > different jar files.
 > 
 > My compiling command is : gcj -o <bm> --main=Harness <bm>.jar <bm>-deps.jar
 > 
 > I've been told by the dacapo folks that the gcj team was also running
 > the dacapo suite. Have you succeed running those benchmarks ? If yes,
 > are there any special things to take care of ?

I think there are a few places where some of the dacapo are explicitly
using non-public interfaces, and there's not much we can do about
that.  I have heard that jfreechart wil now run on a free VM.

 > * The eclipse benchmark from the same suite runs fine with gcj, except
 > that the results aren't very good. Actually, the results are hardly
 > better than what you get when you run the eclipse benchmark with gij.
 > Compare to the others benchmarks results (antlr, hsqldb, luindex,
 > lusearch) where gcj outperforms gij by a factor of 5 or even more, I'm
 > a bit suprised. And using "-O2" or "-Os" for gcj invocation doesn't
 > help.

I'm guessing that eclipse isn't actually spending much time in the
application program itself, but in the libraries.

 > Do you have any thoughts for the reason of such a bad performance ?

I prefer never to guess.  I use oprofile to find out for real.

Andrew.