benchmark on binary trees

[visitor via Digitalmars-d-learn]

version with apr (like in c version)
http://dpaste.dzfl.pl/68c0157225e7
compiled with ldc it's indeed a bit faster on average :
real	0m1.999s
user	0m9.810s
sys	0m0.148

btw Rust version is even faster than my little bit outdated gcc 
(4.9)

latest try with allocators :
http://dpaste.dzfl.pl/86b9b3c4ad71
swallows huge memory, slow !

what am i doing wrong ? (concurrency problem ?)