Application performance and flexibility on exokernel systems

TLDR

The exokernel OS architecture gives untrusted software efficient control over hardware and software resources by separating management from protection. The study presents an exokernel system that lets specialized applications achieve high performance without compromising unmodified UNIX programs, and shares insights and novel resource‑multiplexing techniques from building three exokernel systems. The authors evaluate Xok by measuring end‑to‑end application performance on Intel x86 and comparing it to FreeBSD and OpenBSD, and they present novel resource‑multiplexing techniques. Unmodified UNIX applications perform comparably or better on Xok/ExOS versus BSD UNIXes, while customized applications can gain up to an eight‑fold performance boost by controlling resources.

Abstract

The exokernel operating system architecture safely gives untrusted software efficient control over hardware and software resou rces by separating management from protection. This paper describes an exokernel system that allows specialized applications to achieve high performance without sacrificing the performance of unm odified UNIX programs. It evaluates the exokernel architectur e by measuring end-to-end application performance on Xok, an exokernel for Intel x86-based computers, and by comparing Xok’s performance to the performance of two widely-used 4.4BSD UNIX systems (FreeBSD and OpenBSD). The results show that common unmodified UNIX applications can enjoy the benefits of exoker nels: applications either perform comparably on Xok/ExOS and the BSD UNIXes, or perform significantly better. In addition , the results show that customized applications can benefit subst antially from control over their resources (e.g., a factor of eight fo r a Web server). This paper also describes insights about the exokernel approach gained through building three different exokernel systems, and presents novel approaches to resource multiplexing.