On self-stabilizing wait-free clock synchronization

Abstract

Clock synchronization algorithms which can tolerate any number of processors that can fail by ceasing operation for an unbounded number of steps and resuming operation (with or) without knowing that they were faulty are called Wait-Free. Furthermore, if these algorithms are also able to work correctly even when the starting state of the system is arbitrary, they are called Wait-Free, Self-Stabilizing. This work deals with the problem of Wait-Free, Self-Stabilizing Clock Synchronization of n processors in an “in-phase” multiprocessor system and presents a solution with quadratic synchronization time. The best previous solution has cubic synchronization time. The idea of the algorithm is based on a simple analysis of the difficulties of the problem which helped us to see how to “re-parametrize” the cubic previously mentioned algorithm in order to get the quadratic synchronization time solution. Both the protocol and its analysis are intuitive and easy to understand.