A Complexity-Based Hierarchy for Multiprocessor Synchronization
Faith Ellen, Rati Gelashvili, Nir Shavit, Leqi Zhu · 2016
For many years, Herlihy's elegant computability based Consensus Hierarchy has been our best explanation of the relative power of various types of multiprocessor synchronization objects when used in deterministic algorithms. However, key to this hierarchy is treating these instructions as distinct objects, an approach that is far from the real-world, where multiprocessor programs apply synchronization instructions to collections of arbitrary memory locations. We were surprised to realize that, when considering instructions applied to memory locations, the computability based hierarchy collapses. This leaves open the question of how to better captures the power of various synchronization instructions.