  In this paper we study the scheduling of parallel and real-time recurrent
tasks. Firstly, we propose a new parallel task model which allows recurrent
tasks to be composed of several threads, each thread requires a single
processor for execution and can be scheduled simultaneously. Secondly, we
define several kinds of real-time schedulers that can be applied to our
parallel task model. We distinguish between two scheduling classes:
hierarchical schedulers and global thread schedulers. We present and prove
correct an exact schedulability test for each class. Lastly, we also evaluate
the performance of our scheduling paradigm in comparison with Gang scheduling
by means of simulations.
