Constant RMR group mutual exclusion for arbitrarily many processes and sessions

Liat Maor, Gadi Taubenfeld

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


Group mutual exclusion (GME), introduced by Joung in 1998, is a natural synchronization problem that generalizes the classical mutual exclusion and readers and writers problems. In GME a process requests a session before entering its critical section; processes are allowed to be in their critical sections simultaneously provided they have requested the same session. We present a GME algorithm that (1) is the first to achieve a constant Remote Memory Reference (RMR) complexity for both cache coherent and distributed shared memory machines; and (2) is the first that can be accessed by arbitrarily many dynamically allocated processes and with arbitrarily many session names. Neither of the existing GME algorithms satisfies either of these two important properties. In addition, our algorithm has constant space complexity per process and satisfies the two strong fairness properties, first-come-first-served and first-in-first-enabled. Our algorithm uses an atomic instruction set supported by most modern processor architectures, namely: read, write, fetch-and-store and compare-and-swap.

Original languageEnglish
Title of host publication35th International Symposium on Distributed Computing, DISC 2021
EditorsSeth Gilbert
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959772105
StatePublished - 1 Oct 2021
Externally publishedYes
Event35th International Symposium on Distributed Computing, DISC 2021 - Virtual, Freiburg, Germany
Duration: 4 Oct 20218 Oct 2021

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
ISSN (Print)1868-8969


Conference35th International Symposium on Distributed Computing, DISC 2021
CityVirtual, Freiburg

Bibliographical note

Publisher Copyright:
© Liat Maor and Gadi Taubenfeld; licensed under Creative Commons License CC-BY 4.0


  • Compare&swap (CAS)
  • Fetch&store (FAS)
  • Group mutual exclusion
  • RMR complexity
  • Unbounded number of processes


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