Lock coarsening: Eliminating lock overhead in automatically parallelized object-based programs

  • Pedro Diniz
  • Martin Rinard
Parallelizing Compilers
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1239)


Atomic operations are a key primitive in parallel computing systems. The standard implementation mechanism for atomic operations uses mutual exclusion locks. In an object-based programming system the natural granularity is to give each object its own lock. Each operation can then make its execution atomic by acquiring and releasing the lock for the object that it accesses. But this fine lock granularity may have high synchronization overhead. To achieve good performance it may be necessary to reduce the overhead by coarsening the granularity at which the computation locks objects.

In this paper we describe a static analysis technique — lock coarsening — designed to automatically increase the lock granularity in object-based programs with atomic operations. We have implemented this technique in the context of a parallelizing compiler for irregular, object-based programs. Experiments show these algorithms to be effective in reducing the lock overhead to negligible levels.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Pedro Diniz
    • 1
  • Martin Rinard
    • 1
  1. 1.Department of Computer ScienceUniversity of California, Santa BarbaraSanta Barbara

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