That was one of the "toy" implementations I mentioned. The algorithm they described is going to be nowhere near the performance of a modern multithreaded alloc

That was one of the "toy" implementations I mentioned. The algorithm they described is going to be nowhere near the performance of a modern multithreaded allocator like jemalloc (which is correspondingly far more complex). Which is not to say things like that are not encouraging, only that I was hoping someone would have proven something people actually use correct.