Array append performance

[bearophile]

Robert Jacques:
> I've written some micro benchmarks to test out the difference between an  
> 8-byte struct (i.e. the current arrays) and a 16-byte struct (ptr, length,  
> capacity, stride)

You may want to address some of the things superdan has said.

And, why the stride? I presume it's useful if you want a 2D matrix. It may be useful, but maybe it's overkill, so you may want to benchmark just (ptr, length, capacity) too.
Another useful benchmark is to test a program that manages tons of short strings too, like this one:
http://en.wikipedia.org/wiki/D_language#Example_2

Bye,
bearophile