Atomic snapshots of shared memory

Abstract

An atomic snapshot memory is a shared data structure allowing concurrent processes to store information in a collection of shared registers, all of which may be read in a single atomic scan operation. This paper presents three wait-free implementations of atomic snapshot memory. Two constructions implement wait-free single-writer atomic snapshot memory from wait-free atomic single-writer, n-reader registers. A third construction implements a wait-free n-writer atomic snapshot memory from n-writer, n-reader registers. The first implementation uses unbounded (integer) fields in these registers, while the other implementations use only bounded registers. All operations require Θ(n2) reads and writes to the component shared registers in the worst case.