A simple deterministic algorithm for guaranteeing the forward progress of transactions

Abstract

This paper describes a remarkably simple deterministic (not probabilistic) contention-management algorithm for guaranteeing the forward progress of transactions — avoiding deadlocks, livelocks, and other anomalies. The transactions must be finite (no infinite loops), but on each restart, a transaction may access different shared-memory locations. The algorithm supports irrevocable transactions as long as the transaction satisfies a simple ordering constraint. In particular, a transaction that accesses only one shared-memory location is never aborted. The algorithm is suitable for both hardware and software transactional-memory systems. It also can be used in some contexts as a locking protocol for implementing transactions “by hand.”