Read-Ahead Efficiency on Mobile Devices : Observation, Characterization, and Optimization

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)99-110
Number of pages12
Journal / PublicationIEEE Transactions on Computers
Issue number1
Online published2 Apr 2020
Publication statusPublished - Jan 2021


Read-ahead schemes have been widely used in page cache to improve read performance of Linux systems. As Android system inherits the Linux kernel, the traditional read-ahead scheme is directly transplanted to mobile devices. However, request sizes and page cache sizes on mobile devices are much smaller, which may degrade read-ahead efficiency and therefore hurt user experience. This paper first observes that many pages pre-fetched by read-ahead are unused, which causes frequent page cache eviction. And these evict operations could induce extra access latency, especially when write-back is conducting. Then, this paper proposes a new analysis model to characterize the factors that closely relate to the access latency. It is found that there exists a trade-off between read-ahead size and access latency. Finally, this paper proposes two optimized read-ahead schemes to exploit this trade-off under different situations. Size-tuning scheme aims to find the proper maximum size of read-ahead according to the characteristics of mobile devices. While MobiRA scheme improves the read-ahead efficiency by dynamically tuning read-ahead size and stop-settings. Experimental results on real mobile devices show that the proposed schemes can increase the efficiency of read-ahead scheme and improve the overall performance of mobile devices.

Research Area(s)

  • Mobile handsets, Performance evaluation, Linux, Kernel, User experience, Twitter, Page cache, Read-ahead scheme, Mobile device, Read performance