The Hoard memory allocator is a fast, scalable, and memory-efficient
memory allocator for shared-memory multiprocessors.

Multithreaded programs that perform dynamic memory allocation do not
scale because the heap is a bottleneck. When multiple threads
simultaneously allocate or deallocate memory from the heap, they will
be serialized while waiting for the heap lock. Programs making
intensive use of the heap actually slow down as the number of
processors increases. (Note: If you make a lot of use of the STL, you
may not know it, but you are making a lot of use of the heap.)

Hoard is a fast allocator that solves this problem. In addition, it
has very reasonable bounds on memory consumption.

WWW: http://www.hoard.org/