Using branch prediction information for near-optimal I-cache leakage

Woo Chung Sung, Kevin Skadron

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

5 Citations (Scopus)

Abstract

This paper describes a new on-demand wakeup prediction policy for instruction cache leakage control that achieves better leakage savings than prior policies, and avoids the performance overheads of prior policies. The proposed policy reduces leakage energy by more than 92% with only less than 0.3% performance overhead on average. The key to this new on-demand policy is to use branch prediction information for the wakeup prediction. In the proposed policy, inserting an extra stage for wakeup between branch prediction and fetch, allows the branch predictor to be also used as a wakeup predictor without any additional hardware. Thus, the extra stage hides the wakeup penalty, not affecting branch prediction accuracy. Though extra pipeline stages typically add to branch misprediction penalty, in this case, the extra wakeup stage on the normal fetch path can be overlapped with misprediction recovery. With such consistently accurate wakeup prediction, all cache lines except the next expected cache line are in the leakage saving mode, minimizing leakage energy.

Original languageEnglish
Title of host publicationAdvances in Computer Systems Architecture - 11th Asia-Pacific Conference, ACSAC 2006, Proceedings
Pages24-37
Number of pages14
Publication statusPublished - 2006 Dec 8
Event11th Asia-Pacific Conference on Advances in Computer Systems Architecture, ACSAC 2006 - Shanghai, China
Duration: 2006 Sep 62006 Sep 8

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume4186 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Other

Other11th Asia-Pacific Conference on Advances in Computer Systems Architecture, ACSAC 2006
CountryChina
CityShanghai
Period06/9/606/9/8

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Keywords

  • Branch prediction
  • Drowsy cache
  • Instruction cache
  • Leakage
  • Low power

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

Cite this

Sung, W. C., & Skadron, K. (2006). Using branch prediction information for near-optimal I-cache leakage. In Advances in Computer Systems Architecture - 11th Asia-Pacific Conference, ACSAC 2006, Proceedings (pp. 24-37). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 4186 LNCS).