Old problem with performance

[naryl]

Denis Koroskin Wrote:

> On Sun, 08 Feb 2009 18:40:53 +0300, Denis Koroskin <2korden at gmail.com> wrote:
> 
> > On Sun, 08 Feb 2009 18:09:41 +0300, naryl <cy at ngs.ru> wrote:
> >
> >> It's a bit offtopic but I'd be grateful if someone can explain why D  
> >> with structs completes this simple benchmark (see attachment) so slowly  
> >> compared to C++ with classes on stack:
> >>
> >> D struct - 27.85s
> >> C++ stack - 8.32s
> >>
> >> D class - 271.58s
> >> C++ heap - 249.32s
> >>
> >> Compiled with "dmd -O". -release decreases performance by 10% in this  
> >> case. -inline doesn't affects it at all.
> >
> > I noticed that you calculate Fib(27) in fibs.cc and Fib(40) in fibs.d
> > Can this affect such a big difference between C++ and D version?
> >
> 
> They both perform roughly the same when this typo is corrected.
> 

Sorry. :)

For n=40 I get:
C++ compiled with "g++ -O fibs.cc" - 5.37s
D compiled with "dmd -O -inline fibs.d" - 14.32s
D compiled with "dmd -O -inline -release fibs.d" - 15.20s

DMD 2.023 is still almost three times slower.