Shielded processors: guaranteeing sub-millisecond response in standard Linux

The low latency and preemption patches provide significant progress making standard Linux into a more responsive system for real-time applications. These patches allow guarantees on worst case interrupt response time at slightly above a millisecond. However, these guarantees can only be met when there is no networking or graphics activity in the system. This paper describes the implementation of shielded processors in RedHawk Linux and their benefits. It also presents the results of real time performance benchmarks. Interrupt response time guarantees are significantly below one millisecond and can be guaranteed even in the presence of networking and graphics activity.