Dalibor Topic robilad at yahoo.com
Sat Mar 23 10:52:43 PST 2002

On Friday 22 March 2002 11:27, Jukka Santala wrote:
> On Thu, 21 Mar 2002, Dalibor Topic wrote:
> Now you're confusing me, as well. As noted above, modifying code on one
> platform can affect the performance of other platforms (or other code
> paths) negatively, and I doubt most developers bother to benchmark even on
> their own system after every little change that could've slowed things
> down.

> Hence it would be good idea to provide performance history graphs on
> different platforms so that people can see that "Aha, so something
> committed on April the 1st turned the Gibbering test 50% slower on both
> platforms X and Y, must have been the new gibber-collector I submitted..."

I agree. I test the stuff I (re)implement for performance, but usually don't 
bother testing the performance of small spec conformance fixes.

I would, for example, like to introduce a kaffe.util.param package in a not 
too distant future. There is a lot of parameter checking code in the io 
libraries, and I'd like to factor that out into the param package. The 
package would contain just final classes with static methods. So your typical 
method call to BufferedReader.read(buf, off, len) would call 
kaffe.util.param.Buffer.check(buf, off, len) before it goes on with your read 

Since BufferedReader.read(char [], int, int) already checks its parameters, 
this would in effect de-inline that code out of the read method. The 
resulting performance penalty would be eliminated by a JIT compiler that can 
inline final methods. But it would remain on platforms stuck with an 

The interesting question to ask is: Is the adverse effect on performance on 
those platforms big enough to kill this idea? I could only know if people 
submitted benchmark results for those platforms, once the patch is out.

> > In general, if people run kaffe on benchmarks & put the results on the
> > web, I assume that Jim will link to them. If people volunteer to do so
> > regularly,
> That is somewhat what I had in mind. I'm bit reluctant to volunteer, as I
> don't know how long I can contribute, but I should be able to put up
> performance-tracking for AMD Duron and StrongARM at least. Intel platforms
> should be relatively easy to come by.

Sounds great. I could offer results on a Cyrix Psomething+.

Do you have any specific benchmarks in mind? 

dalibor topic

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