Cross-layered view on android storage IO system

Recently, Smart devices and its functions and applications have flourished. And this development has brought one important requirement, the performance. Storage IO performance is especially important because applications and data are all stored in storage. Smart devices often use NAND-based storage because of its high performance and small size. However, storage IO subsystem on operating system is still not optimized to NAND-based storage. And more, from high performance on storage device itself, management overhead in operating system is revealed. On the other hand, Android, one of most popular platform for smart devices, uses eMMC as main storage and eMMC has several features that can achieve much higher performance than before. In this paper, we measure the overhead of each storage IO layer on Linux, the kernel of Android. And also we study about extended features of eMMC.