NZTM: nonblocking zero-indirection transactional memory

  • Authors:

  • Fuad Tabba;Mark Moir;James R. Goodman;Andrew W. Hay;Cong Wang

  • Affiliations:

  • University of Auckland, Auckland, New Zealand;Sun Microsystems Laboratories, Burlington, MA, USA;University of Auckland, Auckland, New Zealand;University of Auckland, Auckland, New Zealand;University of Wisconsin, Madison, WI, USA

  • Venue:
  • Proceedings of the twenty-first annual symposium on Parallelism in algorithms and architectures
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

This paper introduces NZTM, a nonblocking, zero-indirection, object-based, hybrid transactional memory system. NZTM comprises a nonblocking software transactional memory (STM) system that can exploit best-effort hardware transactional memory (HTM) if available to improve performance. Most previous nonblocking software transactional memory implementations pay a significant performance cost in the common case, as compared to simpler, blocking ones. However, blocking is problematic in some cases and unacceptable in others. NZTM is nonblocking, but shares the advantages of recent blocking STM proposals in the common case: it stores object data "in place", avoiding the costly levels of indirection of previous nonblocking STMs, and improves cache performance by collocating object metadata with the data it controls. We also explain how our nonblocking NZSTM algorithm can be substantially simplified using very simple hardware transactions, and evaluate its performance on Sun's forthcoming Rock processor. Our results show that nonblocking support introduces little overhead when compared with blocking STMs, and that NZTM is competitive with LogTM-SE, an unbounded HTM.