Fast File Synching for Flash Storage in Android Devices

• Main Authors: Sung, Po-Han, 宋柏翰
• Other Authors: Chang, Li-Pin
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/15396602469848014985

碩士 === 國立交通大學 === 資訊科學與工程研究所 === 102 === Using hand-held devices is now a part of peoples' lives. Android is one among the most popular operating systems for hand-held devices. Recent research pointed out that application data manipulation in Android systems involves a great deal of file synching operations, which poses a severe negative impact to the write performance. This work introduces an efficient implementation of file synching operations, called \textit{eager synching}, for Android devices equipped with flash storage. The basic idea is simple: when a file is being synched, eager synching writes only the dirty data associated with the file in a sequential log space, reducing the randomness in the write pattern of file synching. Because sequential write is significantly faster than random write in flash storage, this design can effectively reduce the latency of file synching operations. We implemented our eager synching in the ext4 file system, and the experimental results show that the write throughput of real Android applications and storage benchmarks were improved by up to 50\%, and the largest improvement in write sequentiality was 55\%.