Re: 'Base

[Per Sandberg <per.sandberg@bredband.net>]

Ole-Hjalmar Kristensen wrote:
> My gut reaction was also that Ada will always outperform Java, but I
> have found at least one case there this is not true.  I recently wrote
> a simple test program to transpose a two-dimensional array in Java,
> Ada, C++, and C. The purpose was not really to compare languages, but
> to see the effects of caching. There were two different alogrithms
> used, one a simple nested loop, the other a recursive subdivision with
> a nested loop at the lowest level. When the simple nested loop was
> tested with large data sets (~ available RAM on the machines) the
> diffence between Ada, C, and C++ was insignificant, all being 3-4
> times faster than Java. However, when testing the recursive version, I
> found that Java was actually about 10% faster than the other three,
> which again came extremely close to each other. Apparently the JIT
> compiler had plenty of time to do its work and come up with pretty
> optimal code. The other interesting result from the experiment was
> that the recursive  version was from 3-4 to 20 times faster than the
> simple nested loop.
> 
> 
> 
>>>>>>"MK" == Martin Krischik <krischik@users.sourceforge.net> writes:
> 
> <snip>
>     MK> Ada arrays are not a primitive type - they are a quite complex and powerfull
>     MK> type.
> 
>     MK> Performace? Ada allways outperform Java for a start. But Ada's build in
>     MK> checks will also outperform C/C++ when used with all appropriate
>     MK> "assert()"s in place.
> 
> <snip>

This is intresting but i have tried Ada (GNAT/GCC) with different 
optimisation levels and different validity checking.
and fount that ther is a clearly visible diference in performance 
depending on how far the compiler is allowed to go in terms of optimisation.
I have not done any qualified measurments but the guts feeling is that 
the performace may change bye a factor of at least 2 depending on 
compiler switches.
Also worth to mention that as far as i have seen ther is normaly areound 
30% difference in performace when going from "-O0" to "-Os".

/Per