R&D: Practical Enhancement of User Experience in NVMe SSDs

Applied Sciences has published, in Special Issue Operating System Issues in Emerging Systems and Applications, an article written by Seongmin Kim, Kyusik Kim, Department of Computer Engineering, Kwangwoon University, 20, Gwangun-ro, Nowon-gu, Seoul 01897, Korea, Heeyoung Shin, Department of Intelligent System and Embedded Software Engineering, Kwangwoon University, 20, Gwangun-ro, Nowon-gu, Seoul 01897, Korea, and Taeseok Kim, School of Computer and Information Engineering, Kwangwoon University, 20, Gwangun-ro, Nowon-gu, Seoul 01897, Korea.

Abstract: “When processing I/O requests, the current Linux kernel does not adequately consider the urgency of user-centric tasks closely related to user experience. To solve this critical problem, we developed a practical method in this study to enhance user experience in a computing environment wherein non-volatile memory express (NVMe) solid-state drives (SSDs) serve as storage devices. In our proposed scheme, I/O requests that originate from the user-centric tasks were preferentially served across various levels of queues by modifying the multi-queue block I/O layer of the Linux kernel, considering the dispatch method of NVMe SSDs. Our scheme tries to give as fast a path as possible for I/O requests from user-centric tasks among many queues with different levels. Especially, when the SSD is overburdened, it avoids the queues with many pending I/O requests and thus can significantly reduce the I/O latency of user-centric tasks. We implemented our proposed scheme in the Linux kernel and performed practical evaluations on a commercial SSD. The experimental results showed that the proposed scheme achieved significant enhancement in the launch time of five widely used applications by up to ~65%.“