Transactional pointers: Experiences with HTM-based reference counting in C++

Abstract

The most popular programming languages, such as C++ or Java, have libraries and data structures designed to automatically address concurrency hazards in order to run on multiple threads. In particular, this trend has also been adopted in the memory management domain. However, automatic concurrent memory management also comes at a price, leading sometimes to noticeable overhead. In this paper, we experiment with C++ smart pointers and their automatic memorymanagement technique based on reference counting. More precisely, we study how we can use hardware transactional memory (HTM) to avoid costly and sometimes unnecessary atomic operations. Our results suggest that replacing the systematic counting strategy with HTM could improve application performance in certain scenarios, such as concurrent linked-list traversal.