Optimization fun

[Walter Bright via Digitalmars-d]

On 11/7/2014 2:58 PM, Dmitry Olshansky wrote:
> That's the problem with profilers:
>      they say what takes time but not why :)
>
> Often I find myself looking at memcpy at the top of the list, so obvious the
> "textbook" answer is to optimize memcpy ;) In contrast it should be read as "you
> seem to do excessive copying of data".

dmd's profiler will give you a tree showing who called each function how many 
times. This helps a lot with the "why" question.