Brief Announcement: Quasi-Linearizability: Relaxed Consistency for Improved Concurrency

Many linearizable and optimized concurrent algorithms are available for known algorithms and data structures, such as, Queue, Tree, Stack, Counter and Hash Table. However, sometimes these implementations are used in a more relaxed environment, provided as part of larger design pattern where a relaxed linearizability suffices rather than a strict one. Here we provide a quantitative definition of limited non-determinism, a notion we call Quasi Linearizability. Roughly speaking an implementation of an object is quasi linearizable if each run of the implementation is at a bounded "distance" away from some linear run of the object.