Energy-Aware Microprocessor Synchronization: Transactional Memory vs. Locks

One important way in which multiprocessors differ from uniprocessors is in the need to provide programmers the ability to synchronize concurrent access to memory. Transactional memory was proposed as a way of improving throughput especially when the rate of synchronization conflict is low. In this paper we explore power implications of transactional memory on standard and synthetic benchmarks. We propose a new “serial execution” mode that lowers energy consumption during high contention periods by reducing transaction throughput. We conclude that transactional models are a promising approach to low-power synchronization, and serial execution strengthens the energy advantage, but that further work is needed to fully understand how transactions compare to locks at high levels of contention