Slow performance compared to C++, ideas?

[nazriel]

I managed to get it even faster.

[raz at d3 tmp]$ ./a.out
rendering time 282 ms
[raz at d3 tmp]$ ./test
202 ms, 481 μs, and 8 hnsecs

So D version is 1,4x faster than C++ version.
At least on my computer.

Same compilers flags etc

Final code:
http://dpaste.dzfl.pl/61626e88

I guess there is still more room for improvements.

On Friday, 31 May 2013 at 05:49:55 UTC, finalpatch wrote:
> Thanks Nazriel,
>
> It is very cool you are able to narrow the gap to within 1.5x 
> of c++ with a few simple changes.
>
> I checked your version, there are 3 changes (correct me if i 
> missed any):
>
> * Change the (float) constructor from v= [x,x,x] to v[0] = x; 
> v[1] = x; v[2] = x;
Correct

> * Get rid of the (float[]) constructor and use 3 floats instead
It was just for debbuging so compiler would yell at me if I use 
array literal

> * Change class methods to final
Correct

>
> The first change alone shaved off 220ms off the runtime, the 
> 2nd one cuts 130ms
> and the 3rd one cuts 60ms.
>
> Lesson learned: by very very careful about dynamic arrays.
>

Yeah, it is currently a problem with array literals. They're 
always allocated on heap even if they shouldn't be.
Final before methods is something that needs to be remembered