Improving Flash Memory Performance and Reliability for Smartphones With I/O Deduplication

Flash-based storage subsystem is the key component that affects the system performance, reliability, and cost efficiency of Android-based smartphones. In this paper, we first introduce a trace collection tool specifically designed to capture the I/O requests with important content features in Android-based smartphones, which are critically important but rarely available in content-aware designs and optimizations, such as JProbe and Netlink. Based on the analysis of the traces collected from 15 popular mobile applications, we find that 20%-40% of the I/O requests on the I/O critical path of the storage stack are redundant and this data redundancy is minimally shared among different applications. Based on this key observation, we propose a content-aware optimization, called APP-Dedupe, that applies data deduplication on the I/O critical path to improve both performance and efficiency by reducing write amplification and improving GC efficiency of the flash storage on Android smartphones. The evaluation results show that APP-Dedupe reduces the GC overhead by an average of 41.5%, reduces the response times by up to 15.4% and reduces the amount of write data by an average of 45.2%.