I have an experience that perl's own memory allocator is pretty good.

I agree...except that, in its zeal to provide optimal performance, it makes some choices wrt threads that create add'l issues for sharing memory between threads, namely, the thread that malloc()'s something must be the thread to free() it (in order to avoid the overhead of heap locking). Presumably, Hoard avoids this (just how, I haven't yet fully researched).

Which led to my curiousity if anyone had used Hoard (with Perl or anything else), and to ponder if it might be a means to achieve the performance wo/ the threading restrictions.