Kernel-level threads for dynamic, hard real-time environments

The design of a kernel-level thread package for dynamic, hard real-time environments is presented. A highly integrated design is used to ensure predictability. A system description language and real-time programming language are used to specify key properties of threads and thread groups. For a thread, this includes whether or not the thread spawns other threads at run-time, the type of performance guarantee the thread requires, how the thread interacts with other threads, and what processors the thread may execute on. A predictable kernel uses this information along with on-line dynamic guarantees to ensure predictable execution of threads. The first phase of the thread package has been implemented and performance measurements have indicated a 66% improvement in context switching costs.