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UART Publications

Hierarchical Backoff Locks for Nonuniform Communication Architectures

Zoran Radovic and Erik Hagersten

In Proceedings of the Ninth International Symposium on High Performance Computer Architecture (HPCA-9), Anaheim, California, USA, February 2003.


This paper identifies node affinity as an important property for scalable general-purpose locks. Nonuniform communication architectures (NUCAs), for example CC-NUMAs built from a few large nodes or from chip multiprocessors (CMPs), have a lower penalty for reading data from a neighbor's cache than from a remote cache. Lock implementations that encourages handing over locks to neighbors will improve the lock handover time, as well as the access to the critical data guarded by the lock, but will also be vulnerable to starvation. We propose a set of simple software-based hierarchical backoff locks (HBO) that create node affinity in NUCAs. A solution for lowering the risk of starvation is also suggested. The HBO locks are compared with other software-based lock implementations using simple benchmarks, and are shown to be very competitive for uncontested locks while being more than twice as fast for contended locks. An application study also demonstrates superior performance for applications with high lock contention and competitive performance for other programs.

Available as PDF (145 kB)

BibTeX file entry: Radovic:2003:feb

Updated  2003-09-09 11:01:11 by Zoran Radovic.