[kaffe] jetty working kaffe

Dalibor Topic robilad at kaffe.org
Tue Nov 18 09:42:02 PST 2003

Hi Syed,

Please don't include unrelated mails in your posts to the mailing list.

Syed Mudasir ahmed wrote:
> hi,
>    i have fixed the problem with jetty, i able to run
> jetty with kaffe-1.1.1 on powerpc, But it too slow.
> can some help me in optimiseing the speed of kaffe 

You can fiddle with CFLAGS to improve compiler optimisations. Though the 
gains from that with the interpreter would not yield much of a 
performance improvement, I fear.

You can try profiling jetty on kaffe to see where most of the time is 
spent, and try to optimise those methods in the class library. That 
might help, but may also fail. The achievable performance gain depends 
on how much of its time Jetty spends in methods in kaffe's class library.

You can try profiling kaffe, to see where most of the time is spent, in 
order to optimise those functions. That *might* help, though I doubt it 
would help a lot, unless the interpreter or gc are particularly slow 
with the workloads from Jetty.

You can try porting the powerpc jit from janosVM 0.8.0 [1] over to kaffe 
and fixing whatever bugs you find. That's a great fun project, but might 
take you longer than you expect, as you'll have to learn a lot about 
kaffe's internals. This route should yield the biggest performance 
gains, though. The jit should be approximately 10 times faster than the 
interpreter, AFAIK.

On the more speculative side, you could try merging in the threaded 
interpreter patch from [2]. It is supposed to yield a 10% improvement. 
and be up to 3 times by using specific quick instructions.

dalibor topic

[1] http://freshmeat.net/redir/janosvm/14957/url_tgz/janosvm-0.8.0.tar.gz
[2] http://www.complang.tuwien.ac.at/java/kaffe-threaded/

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