Extending The Limited Parallel Model

In the limited parallel computational model for real-time systems, processes competing for a single processor may issue at any time operations on remote co-processors. During such operations, the processor is not idled but may instead be granted to other ready processes. Such systems, though widespread, until recently had to be analysed with approaches intended for other models, at the cost of pessimism. Noting that remote operations exert no interference on locally executing processes, recent analysis for such systems provided tighter bounds on Worst-Case Response Times (WCRTs) than the application of uniprocessor analysis (but still pessimistic). Based on that work, this new approach further reduces the pessimism by examining temporal patterns of local$/$remote execution and extends to handle multi-CPU variants of the model under Fixed Priority Scheduling (FPS). The same approach can serve as a WCRT-based feasibility test for Symmetric Multiprocessor (SMP) systems.