On the nature of progress

Maurice Herlihy, Nir Shavit

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


We identify a simple relationship that unifies seemingly unrelated progress conditions ranging from the deadlock-free and starvation-free properties common to lock-based systems, to non-blocking conditions such as obstruction-freedom, lock-freedom, and wait-freedom. Properties can be classified along two dimensions based on the demands they make on the operating system scheduler. A gap in the classification reveals a new non-blocking progress condition, weaker than obstruction-freedom, which we call clash-freedom. The classification provides an intuitively-appealing explanation why programmers continue to devise data structures that mix both blocking and non-blocking progress conditions. It also explains why the wait-free property is a natural basis for the consensus hierarchy: a theory of shared-memory computation requires an independent progress condition, not one that makes demands of the operating system scheduler.

Original languageEnglish
Title of host publicationPrinciples of Distributed Systems - 15th International Conference, OPODIS 2011, Proceedings
Number of pages16
StatePublished - 2011
Externally publishedYes
Event15th International Conference on Principles of Distributed Systems, OPODIS 2011 - Toulouse, France
Duration: 13 Dec 201116 Dec 2011

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume7109 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference15th International Conference on Principles of Distributed Systems, OPODIS 2011


Dive into the research topics of 'On the nature of progress'. Together they form a unique fingerprint.

Cite this