Partial synchrony based on set timeliness

  • Authors:

  • Marcos K. Aguilera;Carole Delporte-Gallet;Hugues Fauconnier;Sam Toueg

  • Affiliations:

  • Microsoft Research Silicon Valley, Mountain View, CA, USA;Université Paris 7, Paris, France;Université Paris 7, Paris, France;University of Toronto, Toronto, ON, Canada

  • Venue:
  • Proceedings of the 28th ACM symposium on Principles of distributed computing
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

We introduce a new model of partial synchrony for read-write shared memory systems. This model is based on the notion of set timeliness--a natural and straightforward generalization of the seminal concept of timeliness in the partially synchrony model of Dwork, Lynch and Stockmeyer [8]. Despite its simplicity, the concept of set timeliness is powerful enough to describe the first partially synchronous system for read/write shared memory that separates consensus and set agreement: we show that this system has enough timeliness for solving set agreement but not enough for solving consensus. Set timeliness also allows us to define a family of partially synchronous systems of n processes, denoted Skn (1 ≤ k ≤ n − 1), which closely matches the family of k-anti-Ω failure detectors that were recently shown to be the weakest failure detectors for the k-set agreement problem: We prove that for 1 ≤ k ≤ n − 1, Skn is synchronous enough to implement k-anti-Ω but not enough to implement (k − 1)-anti-Ω. The results above show that set timeliness can be used to study and compare the partial synchrony requirements of problems that are strictly weaker than consensus.