Lock-Free Dynamically Resizable Arrays

We present a first lock-free design and implementation of a dynamically resizable array (vector). The most extensively used container in the C++ Standard Template Library (STL) is vector, offering a combination of dynamic memory management and constant-time random access. Our approach is based on a single 32-bit word atomic compare-and-swap (CAS) instruction. It provides a linearizable and highly parallelizable STL-like interface, lock-free memory allocation and management, and fast execution. Our current implementation is designed to be most efficient on multi-core architectures. Experiments on a dual-core Intel processor with shared L2 cache indicate that our lock-free vector outperforms its lock-based STL counterpart and the latest concurrent vector implementation provided by Intel by a large factor. The performance evaluation on a quad dual-core AMD system with non-shared L2 cache demonstrated timing results comparable to the best available lockbased techniques. The presented design implements the most common STL vector’s interfaces, namely random access read and write, tail insertion and deletion, pre-allocation of memory, and query of the container’s size. Using the current implementation, a user has to avoid one particular ABA problem.