Utility-driven Optimization of TTL Cache Hierarchies under Network Delays

Fuente: arXiv
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Autori principali: Elsayed, Karim S., Geyer, Fabien, Rizk, Amr
Natura: Preprint
Pubblicazione: 2024
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author Elsayed, Karim S.
Geyer, Fabien
Rizk, Amr
author_facet Elsayed, Karim S.
Geyer, Fabien
Rizk, Amr
contents We optimize hierarchies of Time-to-Live (TTL) caches under random network delays. A TTL cache assigns individual eviction timers to cached objects that are usually refreshed upon a hit where upon a miss the object requires a random time to be fetched from a parent cache. Due to their object decoupling property, TTL caches are of particular interest since the optimization of a per-object utility enables service differentiation. However, state-of-the-art exact TTL cache optimization does not extend beyond single TTL caches, especially under network delays. In this paper, we leverage the object decoupling effect to formulate the non-linear utility maximization problem for TTL cache hierarchies in terms of the exact object hit probability under random network delays. We iteratively solve the utility maximization problem to find the optimal per-object TTLs. Further, we show that the exact model suffers from tractability issues for large hierarchies and propose a machine learning approach to estimate the optimal TTL values for large systems. Finally, we provide numerical and data center trace-based evaluations for both methods showing the significant offloading improvement due to TTL optimization considering the network delays.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04402
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Utility-driven Optimization of TTL Cache Hierarchies under Network Delays
Elsayed, Karim S.
Geyer, Fabien
Rizk, Amr
Networking and Internet Architecture
We optimize hierarchies of Time-to-Live (TTL) caches under random network delays. A TTL cache assigns individual eviction timers to cached objects that are usually refreshed upon a hit where upon a miss the object requires a random time to be fetched from a parent cache. Due to their object decoupling property, TTL caches are of particular interest since the optimization of a per-object utility enables service differentiation. However, state-of-the-art exact TTL cache optimization does not extend beyond single TTL caches, especially under network delays. In this paper, we leverage the object decoupling effect to formulate the non-linear utility maximization problem for TTL cache hierarchies in terms of the exact object hit probability under random network delays. We iteratively solve the utility maximization problem to find the optimal per-object TTLs. Further, we show that the exact model suffers from tractability issues for large hierarchies and propose a machine learning approach to estimate the optimal TTL values for large systems. Finally, we provide numerical and data center trace-based evaluations for both methods showing the significant offloading improvement due to TTL optimization considering the network delays.
title Utility-driven Optimization of TTL Cache Hierarchies under Network Delays
topic Networking and Internet Architecture
url https://arxiv.org/abs/2405.04402