AUTONOMOUS OVERLOAD CONTROL FOR DISTRIBUTED REAL TIME SYSTEMS

A method of responding to overload in a real time control system. Overload is measured through the use of a control parameter such as the occupancy of a contr ol processor or the number of entries in a queue of a module of the system. The ove rload indication is reduced to one of a plurality of levels. The levels corresponding to a longer term more serious overload are based on control parameter measurements over a lo nger period of time than the less serious short term overload levels. With autonomous control, each module of the system determines its own overload level and perform s overload control actions corresponding to that level. In integrated system overl oad control, a centralized processor receives overload indications from each of the modules of the system and requests an appropriate overload control action of each module . Advantageously, these arrangements allow the system and its modules to respond t o overload more rapidly and to return to normal operation more rapidly.