We Win! [Was Re: Speed Impact experiment on GCJ]

Wed Feb 15 19:48:00 GMT 2006

Great! Congratulations! But in all fairness you should probably compare 
with experimental versions of other JVM's ;-) (you will probably win 
anyway since the actual program is way to simple to benefit from 
optimizations that are based on heuristic collected at runtime).
Has anyone tried using spec-jAppServer2004 or spec-JBB2005? 
(http://www.spec.org).
Regards,
Thomas Hallgren
Andrew Haley wrote:
> Thomas Hallgren writes:
> > Andrew Haley wrote:
> > > I tried gcj against IBM's JIT -- still the fastest JIT AFAIAA.
> > > (Disclaimer: this is an old 32-bit version of IBM's JIT, and a newer
> > > one may be better.)
> > > 
> > 
> > I made some similar tests using the HotSpot 1.5.0_06 server JVM on a Fedora Core release 4. 
> > As you can see, my gcj is slightly older then yours. Don't know how much that matters. 
> > Results below:
> > 
> > Regards,
> > Thomas Hallgren
> > 
> > 
> > [thhal@localhost gcjtest]$ gcj --version
> > gcj (GCC) 4.0.0 20050519 (Red Hat 4.0.0-8)
> > Copyright (C) 2005 Free Software Foundation, Inc.
> > This is free software; see the source for copying conditions. There is NO
> > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> > 
> > [thhal@localhost gcjtest]$ java -version -server
> > java version "1.5.0_06"
> > Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
> > Java HotSpot(TM) Server VM (build 1.5.0_06-b05, mixed mode)
> > 
> > HotSpot server without JIT:
> > 
> > [thhal@localhost gcjtest]$ time java -server -Djava.compiler=none Client task.test servers.d 
> > result.d
> > 
> > real 0m55.379s
> > user 0m53.726s
> > sys 0m1.379s
> > 
> > 200.0 7897
> > 300.0 11791
> > 400.0 15660
> > 500.0 19588
> > 
> > HotSpot server JIT:
> > 
> > [thhal@localhost gcjtest]$ time java -server Client task.test servers.d result.d
> > 
> > real 0m0.510s
> > user 0m0.073s
> > sys 0m0.393s
> > 
> > 200.0 39
> > 300.0 1
> > 400.0 0
> > 500.0 1
> > 
> > REMARK: Obviously, the JIT discovers that the loop is not really a loop sometime
> > during the first iterations and decides to optimize pretty hard...
>> With a later version of gcj:
>> gcj (GCC) 4.2.0 20060209 (experimental)
> Copyright (C) 2006 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>> [aph@zorro ~]$ time ./client task.test servers.d result.d
>> real 0m0.066s
> user 0m0.044s
> sys 0m0.020s
>> 200.0 0
> 300.0 0
> 400.0 0
> 500.0 0
>> :-)
>> Andrew.
>