A User-space Storage I/O Framework for NVMe SSDs in Mobile Smart Devices

As the application of smart devices becomes more complex, the number of file I/Os has been increased on mobile devices, making the storage performance plays an important role in ensuring better user experience. According to this trend, various researches have been performed to reduce the storage I/O or to improve the performance of the storage device itself. However, existing schemes are not a fundamental solution for improving the storage performance and limited to specific parts of the entire storage layers. In this study, a new storage I/O framework, called NVMeDirect, is proposed to improve the storage performance. The proposed framework improves the performance by allowing applications to access storage directly without any hardware modification. Also, a lightweight filesystem, operated on top of the proposed framework is provided to enable existing applications to be ported on the NVMeDirect framework easily. To evaluate the proposed I/O framework, we have conducted extensive experiments with micro-benchmark and real-world workloads. The experiment results show that, compared to the existing kernel I/O scheme, the proposed framework improves the small file I/O performance by 12.5% and the real-world mobile workload performance by up to 20%.