A NUCA substrate for flexible CMP cache sharing

  • Authors:
  • Jaehyuk Huh;Changkyu Kim;Hazim Shafi;Lixin Zhang;Doug Burger;Stephen W. Keckler

  • Affiliations:
  • The University of Texas at Austin;The University of Texas at Austin;Austin Research Laboratory, IBM Research;Austin Research Laboratory, IBM Research;The University of Texas at Austin;The University of Texas at Austin

  • Venue:
  • Proceedings of the 19th annual international conference on Supercomputing
  • Year:
  • 2005

Quantified Score

Hi-index 0.00



We propose an organization for the on-chip memory system of a chip multiprocessor, in which 16 processors share a 16MB pool of 256 L2 cache banks. The L2 cache is organized as a non-uniform cache architecture (NUCA) array with a switched network embedded in it for high performance. We show that this organization can support the spectrum of degrees of sharing: unshared, in which each processor has a private portion of the cache, thus reducing hit latency, completely shared, in which every processor shares the entire cache, thus minimizing misses, and every point in between. We find the optimal degree of sharing for a number of cache bank mapping policies, and also evaluate a per-application cache partitioning strategy. We conclude that a static NUCA organization with sharing degrees of two or four work best across a suite of commercial and scientific parallel workloads. We also demonstrate that migratory, dynamic NUCA approaches improve performance significantly for a subset of the workloads at the cost of increased power consumption and complexity, especially as per-application cache partitioning strategies are applied.