Re: Truly later thinking...Honey, grab me another beer

[Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>]

Thorbjørn Ravn Andersen wrote:
> Joe Pluta skrev  den 12-08-2008 17:01:
>   
> > > Depends on the language.
> > >     
> > >       
> > No, it doesn't.
> >   
> >     
> Yes it does.  Depends on the libraries called.
>   
No it doesn't.  :)  The same code compiled is ALWAYS faster than the 
same code interpreted.

> (And lets not even get into situations where the speed is not cpu-bound..)
>   
It doesn't matter.  Interpreted code must execute the same number of 
instructions as compiled code, but it also must interpret the source.  
Unless you've entered an alternate universe where you can execute clock 
cycles in negative time, the cycles required to interpret the code make 
it slower.

This is not subject to debate or opinion.  This is simple math.

> First of all it takes MUCH longer to write correctly in C and secondly 
> you are wrong as Perl is calling correctly written C code internally :)
>   
It doesn't matter.  The amount of time taken to write the code is not at 
issue here.

And while Perl may be calling C, the extra code required to interpret 
the source before it calls C adds extra cycles.  So it will be slower 
than native C calling the same routines.  Back to math.

> Thank you.   I have previously done some extensive benchmarking to 
> identify which worked best for us, and I found that the JIT compiler 
> (this is for Classic) was the fastest.  Even faster than opt40. 
>   
I agree.  JIT compilation is almost always the best.


> HotSpot is really tough programming.  It is so nice that we all benefit 
> from the lessons learned that runtime profiling and optimization gives 
> the best performance, and that we get access to it just by using a 
> language running on the JVM.
>   
Agreed again.  That's one of the reasons I prefer Java as my UI 
platform.  It has an extensive community of people working on nothing 
but optimizing the compiler.  Can't say that for a lot of other 
languages.  Of course, when it comes to database processing, the RPG 
compiler team is pretty good at optimizations as well.  But that's what 
IBM does best - system level programming.  I think most of the patents 
in optimization come out of IBM.

Joe