GC performances

[Lutger]

Another interesting thing here is that the Java version beats all other 
languages too, including the ones with manual memory management. But it 
does cost a lot of memory.

I would guess that this is an ideal case for a copying garbage 
collector? I wonder how much of an improvement such a GC will have in 
normal applications, and how hard it will be to implement in D. Another 
concern is what changes are needed in client code to work nicely with a 
copying GC.

But this example does show how relative these microbenchmarks are. After 
all, it costs the Java version more than ten times the memory to 
outperform D, how will that affect the speed of a complex application?

btw. I tried implementing this with a freelist, as suggested by the 
article at the digitalmars site, but it was slower than manual memory 
management. Might be because the code for allocation wasn't inlined for 
some reason.

Likely not the intent of the benchmark, but an array based 
implementation could be faster here.