Performance analysis of BSTs in system software

Binary search tree (BST) based data structures, such as AVL trees, red-black trees, and splay trees, are often used in system software, such as operating system kernels. Choosing the right kind of tree can impact performance significantly, but the literature offers few empirical studies for guidance. We compare 20 BST variants using three experiments in real-world scenarios with real and artificial workloads. The results indicate that when input is expected to be randomly ordered with occasional runs of sorted order, red-black trees are preferred; when insertions often occur in sorted order, AVL trees excel for later random access, whereas splay trees perform best for later sequential or clustered access. For node representations, use of parent pointers is shown to be the fastest choice, with threaded nodes a close second choice that saves memory; nodes without parent pointers or threads suffer when traversal and modification are combined; maintaining a in-order doubly linked list is advantageous when traversal is very common; and right-threaded nodes perform poorly.