A hierarchical model of data locality

Chengliang Zhang, Chen Ding, Mitsunori Ogihara, Yutao Zhong, Youfeng Wu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Scopus citations


In POPL 2002, Petrank and Rawitz showed a universal result-finding optimal data placement is not only NP-hard but also impossible to approximate within a constant factor if P ≠ NP. Here we study a recently published concept called reference affinity, which characterizes a group of data that are always accessed together in computation. On the theoretical side, we give the complexity for finding reference affinity in program traces, using a novel reduction that converts the notion of distance into satisfiability. We also prove that reference affinity automatically captures the hierarchical locality in divide-and-conquer computations including matrix solvers and N-body simulation. The proof establishes formal links between computation patterns in time and locality relations in space. On the practical side, we show that efficient heuristics exist. In particular, we present a sampling method and show that it is more effective than the previously published technique, especially for data that are often but not always accessed together. We show the effect on generated and real traces. These theoretical and empirical results demonstrate that effective data placement is still attainable in general-purpose programs because common (albeit not all) locality patterns can be precisely modeled and efficiently analyzed.

Original languageEnglish (US)
Title of host publicationConference Record of POPL 2006
Subtitle of host publication33rd ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages
Number of pages14
StatePublished - Jul 17 2006
Externally publishedYes

Publication series

NameConference Record of the Annual ACM Symposium on Principles of Programming Languages
ISSN (Print)0730-8566


  • Hierarchical data placement
  • N-body simulation
  • NP-complete
  • Program locality
  • Reterence affinity
  • Volume distance

ASJC Scopus subject areas

  • Software

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  • Cite this

    Zhang, C., Ding, C., Ogihara, M., Zhong, Y., & Wu, Y. (2006). A hierarchical model of data locality. In Conference Record of POPL 2006: 33rd ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (pp. 16-29). (Conference Record of the Annual ACM Symposium on Principles of Programming Languages).