Safe privatization in transactional memory

Artem Khyzha*, Hagit Attiya, Alexey Gotsman, Noam Rinetzky

*Corresponding author for this work

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

6 Scopus citations


Transactional memory (TM) facilitates the development of concurrent applications by letting the programmer designate certain code blocks as atomic. Programmers using a TM often would like to access the same data both inside and outside transactions, e.g., to improve performance or to support legacy code. In this case, programmers would ideally like the TM to guarantee strong atomicity, where transactions can be viewed as executing atomically also with respect to non-transactional accesses. Since guaranteeing strong atomicity for arbitrary programs is prohibitively expensive, researchers have suggested guaranteeing it only for certain data-race free (DRF) programs, particularly those that follow the privatization idiom: From some point on, threads agree that a given object can be accessed non-transactionally. Supporting privatization safely in a TM is nontrivial, because this often requires correctly inserting transactional fences, which wait until all active transactions complete. Unfortunately, there is currently no consensus on a single definition of transactional DRF, in particular, because no existing notion of DRF takes into account transactional fences. In this paper we propose such a notion and prove that, if a TM satisfies a certain condition generalizing opacity and a program using it is DRF assuming strong atomicity, then the program indeed has strongly atomic semantics. We show that our DRF notion allows the programmer to use privatization idioms. We also propose a method for proving our generalization of opacity and apply it to the TL2 TM.

Original languageEnglish
Title of host publicationPPoPP 2018 - Proceedings of the 23rd Principles and Practice of Parallel Programming
PublisherAssociation for Computing Machinery
Number of pages13
ISBN (Electronic)9781450349826
StatePublished - 10 Feb 2018
Event23rd ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming, PPoPP 2018 - Vienna, Austria
Duration: 24 Feb 201828 Feb 2018

Publication series

NameProceedings of the ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming, PPOPP


Conference23rd ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming, PPoPP 2018


  • Observational refinement
  • Privatization
  • Software transactional memory
  • Strong atomicity


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