Improving Disk Performance in Vortex With NVMe

Abstract

With the development of SSDs, performance limitations in persistent storage have shifted from the underlying medium to the interface through which the host and disk communicates. NVMe is a recently developed standard for operating SSDs connected to a host through PCI Express, and offers significant performance improvements compared to conventional interfaces, as well as features designed for multi-tenant environments. Vortex is an experimental implementation of the omni-kernel architecture, a novel operating system kernel designed to offer strong isolation and accurate, fine-grained scheduling of system resources for all tenants that share a platform. The BIOS of the hardware platform currently supported by Vortex does not recognize NVMe devices, and the Vortex operating system does not support configuration of devices that are unrecognized by the BIOS. Further, the storage stack implemented in Vortex only supports SCSI-based storage devices. This thesis presents the implementation of an NVMe driver for Vortex that is exposed as a SCSI device. We also implement a system for recovering information about devices that are unrecognized by the BIOS, and use this system to successfully configure NVMe devices on our hardware platform. The NVMe driver is fully functional, deployed in a running Vortex system, and evaluated through performance experiments.