A wait-free queue with polylogarithmic step complexity

In the late panel session, Maurice Herlihy questioned whether the Actor model [1] could implement wait-free shared queue. Processes are guaranteed to complete queue operations in a finite amount of steps even if other processes may fail at arbitrary points. Consequently, the queue may not have an implementation based on mutual exclusion, but may be implemented with non-trivial atomic operations. Gul Agha did not provide a method for implementing such an abstraction, but argued that the techniques used to implement the wait-free queue would also apply to implementing the Actor model.The Matroshka model (described in the position statement "A Uniform Object Model for Parallel Programming" within these proceedings and [2]) can implement both wait-free queues and the Actor model of computation.