R&D: Understanding Modern Storage APIs, Systematic Study of Libaio, SPDK, and io_Uring

ACM Digital Library has published, in SYSTOR ’22: Proceedings of the 15th ACM International Conference on Systems and Storage, an article written by Diego Didona, Jonas Pfefferle, Nikolas Ioannou, Bernard Metzler, IBM Research Europe, Zurich, Switzerland, and Animesh Trivedi, VU Amsterdam, Amsterdam, Netherlands.

Abstract: “Recent high-performance storage devices have exposed software inefficiencies in existing storage stacks, leading to a new breed of I/O stacks. The newest storage API of the Linux kernel is io_uring. We perform one of the first in-depth studies of io_uring, and compare its performance and dis-/advantages with the established libaio and SPDK APIs. Our key findings reveal that (i) polling design significantly impacts performance; (ii) with enough CPU cores io_uring can deliver performance close to that of SPDK; and (iii) performance scalability over multiple CPU cores and devices requires careful consideration and necessitates a hybrid approach. Last, we provide design guidelines for developers of storage intensive applications.“