Real-time scheduling of CPU-bound and I/O-bound processes

The real-time resource allocation problem has been an active research topic in recent decades. Although the real-time resource allocation problem has been analyzed for different architectural assumptions, various simplified assumptions on resource synchronization are made for real-time process scheduling. Little work has been done in scheduling processes which may requests services from other independent subsystems. This paper explores real-time scheduling of processes which may share non-preemptible resources on the same processor and, at the same time, request services from other independent subsystems. In particular we consider the scheduling of real-time processes which may stop to wait for disk I/O without releasing any locked semaphores. We propose to revise the definition of priority ceiling and propose a resource synchronization mechanism to meet the deadline requirements of real-time CPU-bound and I/O-bound processes. The capability of the proposed methodology is verified by a series of simulation experiments on different workloads of CPU-bound and I/O-bound processes, for which we have some encouraging experimental results.