Linearizability

Years and Authors of Summarized Original Work

• 1990; Herlihy, Wing

Problem Definition

An object in languages such as Java and C++ is a container for data. Each object provides a set of methods that are the only way to to manipulate that object's internal state. Each object has a class which defines the methods it provides and what they do.

In the absence of concurrency, methods can be described by a pair consisting of a precondition (describing the object's state before invoking the method) and a postcondition, describing, once the method returns, the object's state and the method's return value. If, however, an object is shared by concurrent threads in a multiprocessor system, then method calls may overlap in time, and it no longer makes sense to characterize methods in terms of pre- and post-conditions.

Linearizabilityis a correctness condition for concurrent objects that characterizes an object's concurrent behavior in terms of an “equivalent” sequential behavior. Informally, the...