A Type System for Data-Centric Synchronization

Data-centric synchronization groups fields of objects into atomic sets to indicate they must be updated atomically. Each atomic set has associated units of work, code fragments that preserve the consistency of that atomic set. We present a type system for data-centric synchronization that enables separate compilation and supports atomic sets that span multiple objects, thus allowing recursive data structures to be updated atomically. The type system supports full encapsulation for more efficient code generation. We evaluate our proposal using AJ, which extends the Java programming language with data-centric synchronization. We report on the implementation of a compiler and on refactoring classes from standard libraries and a multi-threaded benchmark to use atomic sets. Our results suggest that data-centric synchronization enjoys low annotation overhead while preventing high-level data races.