Speeding up STL Set/Map Usage in C++ Applications

Abstract

In this work we augment the red-black tree implementation of STL set< ... >/map< ... > with a doubly linked list that is in sorted order. This is done for the purpose of speeding up C++ applications that use set< >/map< >::iterator considerably. In such cases, the doubly linked list helps in iterating over the set< >/map< > quickly. Usually the ++/– operations have an amortized cost of O(1) for a red-black tree implementation. The linked list augmentation helps in improving the ++/– operations to Θ(1). In addition, our experiments for IBM’s P5+ and P6 processors show that this mechanism improves performance for two SPEC CPU2006 benchmarks and there is no adverse cache effect when we support two additional pointers per node of a red-black tree.