WiDir: A Wireless-Enabled Directory Cache Coherence Protocol

Antonio Franques, Apostolos Kokolis, Sergi Abadal, Vimuth Fernando, Sasa Misailovic, Josep Torrellas

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

Abstract

As the core count in shared-memory manycores keeps increasing, it is becoming increasingly harder to design cache-coherence protocols that deliver high performance without an inordinate increase in complexity and cost. In particular, sharing patterns where a group of cores frequently reads and writes a shared variable are hard to support efficiently. Hence, programmers end up tuning their applications to avoid these patterns, hurting the programmability of shared memory. To address this problem, this paper uses the recently-proposed on-chip wireless network technology to augment a conventional invalidation-based directory cache coherence protocol. We call the resulting protocol WiDir. WiDir seamlessly transitions between wired and wireless coherence transactions for a given line based on the access patterns in a programmer-Transparent manner. In this paper, we describe the protocol transitions in detail. Further, an evaluation using SPLASH and PARSEC applications shows that WiDir substantially reduces the memory stall time of applications. As a result, for 64-core runs, WiDir reduces the execution time of applications by an average of 22% compared to a conventional directory protocol. Moreover, WiDir is more scalable. These benefits are obtained with a very modest power cost.

Original languageEnglish (US)
Title of host publicationProceeding - 27th IEEE International Symposium on High Performance Computer Architecture, HPCA 2021
PublisherIEEE Computer Society
Pages304-317
Number of pages14
ISBN (Electronic)9780738123370
DOIs
StatePublished - Feb 2021
Event27th Annual IEEE International Symposium on High Performance Computer Architecture, HPCA 2021 - Virtual, Seoul, Korea, Republic of
Duration: Feb 27 2021Mar 1 2021

Publication series

NameProceedings - International Symposium on High-Performance Computer Architecture
Volume2021-February
ISSN (Print)1530-0897

Conference

Conference27th Annual IEEE International Symposium on High Performance Computer Architecture, HPCA 2021
Country/TerritoryKorea, Republic of
CityVirtual, Seoul
Period2/27/213/1/21

Keywords

  • Directory cache coherence protocol
  • Multicore
  • Wireless Network on chip

ASJC Scopus subject areas

  • Hardware and Architecture

Fingerprint

Dive into the research topics of 'WiDir: A Wireless-Enabled Directory Cache Coherence Protocol'. Together they form a unique fingerprint.

Cite this