Challenge: write a reference counted slice that works as much as possible like a built-in slice

[Ola Fosheim Grøstad]

On Friday, 12 November 2021 at 22:10:22 UTC, H. S. Teoh wrote:
> This is why I also say, why are people so hung up about the GC? 
>  If your inner loops have performance problems with the GC, 
> then rewrite it as @nogc, use malloc/free/whatever it takes to 
> make it faster.

If you have a large scannable heap then scanning will pollute the 
shared memory caches. Unless your scanning code use load/save 
instructions that bypass the caches. So in essence GC collection 
affects the whole system, also @nogc code. Another downside of 
imprecise scanning is that you need to zero out memory in order 
to make sure memory gets freed.

Now, if you tied a fully precise GC to a smaller unit, like a 
computation, then you could get better performance than other 
schemes since you often could just drop the whole heap without 
scanning when the computation is complete.

But the chosen path for D does not allow this, as of today, which 
does give people reason to wonder about the future direction for 
language evolution.