Soft-OLP: Improving hardware cache performance through software-controlled object-level partitioning

Qingda Lu, Jiang Lin, Xiaoning Ding, Zhao Zhang, Xiaodong Zhang, P. Sadayappan

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

48 Scopus citations

Abstract

Performance degradation of memory-intensive programs caused by the LRU policy's inability to handle weaklocality data accesses in the last level cache is increasingly serious for two reasons. First, the last-level cache remains in the CPU's critical path, where only simple management mechanisms, such as LRU, can be used, precluding some sophisticated hardware mechanisms to address the problem. Second, the commonly used shared cache structure of multi-core processors has made this critical path even more performance-sensitive due to intensive inter-thread contention for shared cache resources. Researchers have recently made efforts to address the problem with the LRU policy by partitioning the cache using hardware or OS facilities guided by run-time locality information. Such approaches often rely on special hardware support or lack enough accuracy. In contrast, for a large class of programs, the locality information can be accurately predicted if access patterns are recognized through small training runs at the data object level. To achieve this goal, we present a system-software framework referred to as Soft-OLP (Software-based Object-Level cache Partitioning). We first collect per-object reuse distance histograms and inter-object interference histograms via memory-trace sampling. With several low-cost training runs, we are able to determine the locality patterns of data objects. For the actual runs, we categorize data objects into different locality types and partition the cache space among data objects with a heuristic algorithm, in order to reduce cache misses through segregation of contending objects. The object-level cache partitioning framework has been implemented with a modified Linux kernel, and tested on a commodity multi-core processor. Experimental results show that in comparison with a standard L2 cache managed by LRU, Soft-OLP significantly reduces the execution time by reducing L2 cache misses across inputs for a set of single- and multi-threaded programs from the SPEC CPU2000 benchmark suite, NAS benchmarks and a computational kernel set.

Original languageEnglish (US)
Title of host publicationProceedings - 2009 18th International Conference on Parallel Architectures and Compilation Techniques, PACT 2009
Pages246-257
Number of pages12
DOIs
StatePublished - 2009
Externally publishedYes
Event2009 18th International Conference on Parallel Architectures and Compilation Techniques, PACT 2009 - Raleigh, NC, United States
Duration: Sep 12 2009Sep 16 2009

Publication series

NameParallel Architectures and Compilation Techniques - Conference Proceedings, PACT
ISSN (Print)1089-795X

Other

Other2009 18th International Conference on Parallel Architectures and Compilation Techniques, PACT 2009
Country/TerritoryUnited States
CityRaleigh, NC
Period9/12/099/16/09

All Science Journal Classification (ASJC) codes

  • Software
  • Theoretical Computer Science
  • Hardware and Architecture

Keywords

  • Cache partitioning
  • Page coloring
  • Reuse distance
  • Software-controlled caching

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