iPatch: Intelligent fault patching to improve energy efficiency

David J. Palframan, Nam Sung Kim, Mikko H. Lipasti

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

Abstract

Dynamic voltage and frequency scaling can provide substantial energy savings but is limited by SRAM since some cells will fail at very low voltages. Due to process variation effects, a small subset of SRAM cells will be more sensitive to voltage reduction, requiring increased margins and limiting energy savings. Since large arrays like caches are most vulnerable to cell failures, recent proposals suggest disabling failing portions of the cache to enable low voltage operation. Although such approaches save power, energy reduction is limited because reducing the effective cache size increases program runtimes. In this paper, we present iPatch, a solution to regain this lost performance and enable energy savings by exploiting the redundancy inherent in superscalar processors. By relying on existing microarchitectural structures and mechanisms to 'patch' the faulty parts of caches, we enable further energy reduction with minimal overhead and complexity. Furthermore, because no critical paths or circuits are affected by our implementation, there is no impact on normal-voltage operation. For high cell failure rates, our results show significant energy savings with iPatch as well as an 18% reduction in energy-delay product compared to prior work.

Original languageEnglish (US)
Title of host publication2015 IEEE 21st International Symposium on High Performance Computer Architecture, HPCA 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages428-438
Number of pages11
ISBN (Electronic)9781479989300
DOIs
StatePublished - Mar 6 2015
Event2015 21st IEEE International Symposium on High Performance Computer Architecture, HPCA 2015 - Burlingame, United States
Duration: Feb 7 2015Feb 11 2015

Publication series

Name2015 IEEE 21st International Symposium on High Performance Computer Architecture, HPCA 2015

Other

Other2015 21st IEEE International Symposium on High Performance Computer Architecture, HPCA 2015
CountryUnited States
CityBurlingame
Period2/7/152/11/15

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Hardware and Architecture
  • Software

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  • Cite this

    Palframan, D. J., Kim, N. S., & Lipasti, M. H. (2015). iPatch: Intelligent fault patching to improve energy efficiency. In 2015 IEEE 21st International Symposium on High Performance Computer Architecture, HPCA 2015 (pp. 428-438). [7056052] (2015 IEEE 21st International Symposium on High Performance Computer Architecture, HPCA 2015). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/HPCA.2015.7056052