On interrupt scheduling based on process priority for predictable real-time behavior

Traditionally, kernel services are of a higher priority than user processes. The kernel can preempt the currently executed process in order to perform interrupt handling for the behalf of another process, even though the latter process is of a lower priority than the former. This can be viewed as priority inversion. We propose a new interrupt handling approach that couples interrupt scheduling with the priority of a process associated with the interrupt to handle. We present techniques to derive exact process priorities in handling interrupts for incoming network packets. The proposed approach has been implemented in Linux 2.6, and experiment results show that it reduces interference of lower priority processes to higher-priority process through interrupt handling.