System Support for Online Reconfiguration
Craig A. N. Soules, Jonathan Appavoo, Kevin Hui, Robert W. Wisniewski, Dilma Da Silva, Gregory R. Ganger, Orran Krieger, Michael Stumm, Marc Auslander, Michal Ostrowski, Bryan S. Rosenburg, Jimi Xenidis · 2003
Online reconfiguration provides a way to extend and replace active operating system components. This provides administrators, developers, applications, and the system itself with a way to update code, adapt to changing workloads, pinpoint performance problems, and perform a variety of other tasks all while the system is running. With generic support for interposition and hot-swapping, a system allows active components to be wrapped with additional functionality or replaced with a different implementations that have the same interfaces. This paper identifies four support mechanisms required by online reconfiguration. It describes each mechanism’s implementation in the K42 operating system, and how they are combined to implement interposition and hotswapping. It then illustrates some dynamic performance enhancements achievable with K42’s online reconfiguration including: adaptive algorithms, common case optimizations, and workload specific specializations.