HybridTier: an Adaptive and Lightweight CXL-Memory Tiering System

Fuente: arXiv
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Autori principali: Song, Kevin, Yang, Jiacheng, Wang, Zixuan, Zhao, Jishen, Liu, Sihang, Pekhimenko, Gennady
Natura: Preprint
Pubblicazione: 2023
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author Song, Kevin
Yang, Jiacheng
Wang, Zixuan
Zhao, Jishen
Liu, Sihang
Pekhimenko, Gennady
author_facet Song, Kevin
Yang, Jiacheng
Wang, Zixuan
Zhao, Jishen
Liu, Sihang
Pekhimenko, Gennady
contents Modern workloads are demanding increasingly larger memory capacity. Compute Express Link (CXL)-based memory tiering has emerged as a promising solution for addressing this problem by utilizing traditional DRAM alongside slow-tier CXL memory devices. We analyze prior tiering systems and observe two challenges for high-performance memory tiering: adapting to skewed but dynamically varying data hotness distributions while minimizing memory and cache overhead due to tiering. To address these challenges, we propose HybridTier, an adaptive and lightweight tiering system for CXL memory. HybridTier tracks both long-term data access frequency and short-term access momentum \emph{simultaneously} to accurately capture and adapt to shifting hotness distributions. HybridTier reduces the metadata memory overhead by tracking data accesses \emph{probabilistically}, obtaining higher memory efficiency by trading off a small amount of tracking inaccuracy that has a negligible impact on application performance. To reduce cache overhead, HybridTier uses lightweight data structures that optimize for data locality to track data hotness. Our evaluations show that HybridTier outperforms prior systems by up to $91\%$ ($19\%$ geomean), incurring $2.0-7.8\times$ less memory overhead and $1.7-3.5\times$ less cache misses.
format Preprint
id arxiv_https___arxiv_org_abs_2312_04789
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle HybridTier: an Adaptive and Lightweight CXL-Memory Tiering System
Song, Kevin
Yang, Jiacheng
Wang, Zixuan
Zhao, Jishen
Liu, Sihang
Pekhimenko, Gennady
Distributed, Parallel, and Cluster Computing
Operating Systems
Modern workloads are demanding increasingly larger memory capacity. Compute Express Link (CXL)-based memory tiering has emerged as a promising solution for addressing this problem by utilizing traditional DRAM alongside slow-tier CXL memory devices. We analyze prior tiering systems and observe two challenges for high-performance memory tiering: adapting to skewed but dynamically varying data hotness distributions while minimizing memory and cache overhead due to tiering. To address these challenges, we propose HybridTier, an adaptive and lightweight tiering system for CXL memory. HybridTier tracks both long-term data access frequency and short-term access momentum \emph{simultaneously} to accurately capture and adapt to shifting hotness distributions. HybridTier reduces the metadata memory overhead by tracking data accesses \emph{probabilistically}, obtaining higher memory efficiency by trading off a small amount of tracking inaccuracy that has a negligible impact on application performance. To reduce cache overhead, HybridTier uses lightweight data structures that optimize for data locality to track data hotness. Our evaluations show that HybridTier outperforms prior systems by up to $91\%$ ($19\%$ geomean), incurring $2.0-7.8\times$ less memory overhead and $1.7-3.5\times$ less cache misses.
title HybridTier: an Adaptive and Lightweight CXL-Memory Tiering System
topic Distributed, Parallel, and Cluster Computing
Operating Systems
url https://arxiv.org/abs/2312.04789