research-article

Foundations of the C++ concurrency memory model

Authors:

Sarita V. AdveAuthors Info & Claims

ACM SIGPLAN Notices, Volume 43, Issue 6

Pages 68 - 78

https://doi.org/10.1145/1379022.1375591

Published: 07 June 2008 Publication History

Abstract

Currently multi-threaded C or C++ programs combine a single-threaded programming language with a separate threads library. This is not entirely sound [7].

We describe an effort, currently nearing completion, to address these issues by explicitly providing semantics for threads in the next revision of the C++ standard. Our approach is similar to that recently followed by Java [25], in that, at least for a well-defined and interesting subset of the language, we give sequentially consistent semantics to programs that do not contain data races. Nonetheless, a number of our decisions are often surprising even to those familiar with the Java effort:

We (mostly) insist on sequential consistency for race-free programs, in spite of implementation issues that came to light after the Java work.

We give no semantics to programs with data races. There are no benign C++ data races.

We use weaker semantics for trylock than existing languages or libraries, allowing us to promise sequential consistency with an intuitive race definition, even for programs with trylock.

This paper describes the simple model we would like to be able to provide for C++ threads programmers, and explain how this, together with some practical, but often under-appreciated implementation constraints, drives us towards the above decisions.

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Index Terms

Foundations of the C++ concurrency memory model
1. Hardware
  1. Integrated circuits
    1. Semiconductor memory
      1. Dynamic memory
2. Software and its engineering
  1. Software notations and tools
    1. General programming languages
      1. Language features
        Concurrent programming structures

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Published In

cover image ACM SIGPLAN Notices

ACM SIGPLAN Notices Volume 43, Issue 6

PLDI '08

June 2008

382 pages

ISSN:0362-1340

EISSN:1558-1160

DOI:10.1145/1379022

Issue’s Table of Contents

PLDI '08: Proceedings of the 29th ACM SIGPLAN Conference on Programming Language Design and Implementation
June 2008
396 pages
ISBN:9781595938602
DOI:10.1145/1375581
General Chair:
Rajiv Gupta
University of California, Riverside, USA
,
Program Chair:
Saman Amarasinghe
Massachusetts Institute of Technology, USA

Copyright © 2008 ACM.

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Publication History

Published: 07 June 2008

Published in SIGPLAN Volume 43, Issue 6

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