Allocator performance testing

[Benjamin Kosnik]

Loren pretty much said it all, and is more expert in this area than I,
but I'll just say this looks pretty promising, and am interested in this
__mt_alloc. Have you looked at libhoard? This sounds somewhat similar.

Additions to the allocator options are always welcome. Other options
that would also be welcome are garbage-collecting allocators and
persistent allocators.

You might also be interested in the email thread (you'll have to search
for it) where gcc-3 switched back to the __pool_alloc from
__malloc_alloc: Loren had some numbers and MT STL test cases for that
switch. I think it happened between 3.0.x and 3.1.x, but it might have
been earlier.

best,
benjamin