A wait-free universal construction for large objects.

Concurrency has been a subject of study for more than 50 years. Still, many developers struggle to adapt their sequential code to be accessed concurrently. This need has pushed for generic solutions and specific concurrent data structures. Wait-free universal constructions are attractive as they can turn a sequential implementation of any object into an equivalent, yet concurrent and wait-free, implementation. Existing universal constructions either maintain a per-thread replica of the object, or make a new copy of the object on every operation, with both approaches yielding low performance. To overcome these limitations, we have designed CX, a multi-instance-based wait-free universal construction that shares replicas among threads using reader-writer locks. CX performs significantly better than existing wait-free constructions for our tested sequential data structures. Moreover, on read-oriented workloads, CX rivals hand-written lock-free and wait-free data structures. Our universal construction is the first to provide integrated wait-free memory reclamation.