Energy Efficient Runahead Execution on a Tightly Coupled Heterogeneous Core

Susumu Mashimo, Ryota Shioya, Koji Inoue

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

Abstract

Out-of-order (OoO) processors generally offer significant performance gains over simpler in-order (InO) processors. However, recent studies have revealed that OoO processors provide little performance benefit in many program phases, and these phases are distributed in fine granularity. Leveraging these fine-grained phases, tightly coupled heterogeneous cores (TCHCs) have been proposed to improve the energy efficiency. A TCHC, which is a processor core that consists of multiple back-ends, each with different characteristics in terms of their performance and energy consumption (e.g., a power-efficient InO back-end and a high-performance OoO back-end), improves the energy efficiency by executing programs by switching to the most energy-efficient back-end with a very small switching penalty. We propose a novel technique to further improve the energy efficiency of a TCHC. The proposed technique is based on runahead execution (RAE), which is a prefetch technique that executes instructions ahead of long-latency cache misses and issues independent cache misses earlier. Leveraging the characteristics of TCHCs and RAE, the proposed technique increases the utilization of energy-efficient back-ends, thereby significantly improving the energy efficiency. Our evaluation results show that our proposed method achieves 13% of energy-delay product (EDP) over a state-of-the-art TCHC using Oracle switching decision logic.

Original languageEnglish
Title of host publicationProceedings of International Conference on High Performance Computing in Asia-Pacific Region, HPC Asia 2020
PublisherAssociation for Computing Machinery
Pages207-216
Number of pages10
ISBN (Electronic)9781450372367
DOIs
Publication statusPublished - Jan 15 2020
Event2020 International Conference on High Performance Computing in Asia-Pacific Region, HPC Asia 2020 - Fukuoka, Japan
Duration: Jan 15 2020Jan 17 2020

Publication series

NameACM International Conference Proceeding Series

Conference

Conference2020 International Conference on High Performance Computing in Asia-Pacific Region, HPC Asia 2020
CountryJapan
CityFukuoka
Period1/15/201/17/20

All Science Journal Classification (ASJC) codes

  • Human-Computer Interaction
  • Computer Networks and Communications
  • Computer Vision and Pattern Recognition
  • Software

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