Evaluation of Real-Time Synchronization in Real-Time Mach

Real-Time Mach provides real-time thread and real-time synchronization facilities. A real-time thread can be created for a periodic or aperiodic activity with a timing constraint. Threads can be synchronized among them using a real-time version of the monitor based synchronization mechanism with a suitable locking protocol. In Real-Time Mach, we have implemented several locking policies, such as kernelized monitor, basic priority priority inheritance protocol, priority ceiling protocol, and restartable critical section, for real-time applications. It can also avoid a unbounded priority inversion problem. In this paper, we describe the real-time synchronization facilities in Real-Time Mach and its implementation and performance evaluation. Our evaluation results demonstrated that a proper choice of locking policy can avoid unbounded priority inversions and improve the processor schedulability for real-time applications. 1 This research was supported in part by the U.S. Naval Ocean Systems Center under contract number N66001-87-C-0155, by the O ce of Naval Research under contract number N00014-84-K0734, by the Defense Advanced Research Projects Agency, ARPA Order No. 7330 under contract number MDA72-90-C-0035, by the Federal Systems Division of IBM Corporation under University Agreement YA-278067, and by the SONY Corporation. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing o cial policies, either expressed or implied, of NOSC, ONR, DARPA, IBM, SONY, or the U.S. Government.