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Real-time scheduling algorithms for multiprocessor systems have been the subject of considerable recent interest. For such an algorithm to be truly useful in practice, support for semaphore-based locking must be provided. However, for many global scheduling algorithms, no such mechanisms have been proposed. Furthermore, in the partitioned case, most prior(More)
We present a real-time, Linux-based testbed called LITMUS RT , which we have developed for empirically evaluating multiprocessor real-time scheduling algorithms. We also present the results from such an evaluation, in which partitioned earliest-deadline-first (EDF) scheduling, pre-emptive and nonpreemptive global EDF scheduling, and two variants of the(More)
We consider the issue of deadline tardiness under global multiprocessor scheduling algorithms. We present a general tardiness-bound derivation that is applicable to a wide variety of such algorithms (including some whose tardiness behavior has not been analyzed before). Our derivation is very general: job priorities may change rather arbitrarily at runtime,(More)
A multiprocessor scheduling scheme is presented for supporting hierarchical containers that encapsulate sporadic soft and hard real-time tasks. In this scheme, each container is allocated a specified bandwidth, which it uses to scheduled its children (some of which may also be containers). This scheme is novel in that, with only soft real-time tasks, no(More)
We consider coordinating accesses to shared data structures in multiprocessor real-time systems scheduled under preemptive global EDF. To our knowledge, prior work on global EDF has focused only on systems of independent tasks. We take an initial step here towards a generic resource-sharing framework by considering simple shared objects, such as queues,(More)
In the domain of multiprocessor real-time systems, there has been a wealth of recent work on scheduling, but relatively little work on the equally-important topic of synchronization. When synchronizing accesses to shared resources, four basic options exist: lock-free execution, wait-free execution, spin- based locking, and suspension-based locking. To our(More)
The importance of accounting for interrupts in multiprocessor real-time schedulability anal-sysis is discussed and three interrupt accounting methods, namely quantum-centric, task-centric, and processor-centric accounting, are analyzed and contrasted. Additionally, two special cases, dedicated interrupt handling (i.e., all interrupts are processed by one(More)
The issue of deadline tardiness is considered under global earliest-deadline-first (GEDF) multiprocessor scheduling. New schedulability tests are presented for determining whether a set of sporadic tasks with arbitrary relative deadlines can be scheduled under either preemptive or non-preemptive GEDF so that pre-defined tardiness bounds are met. These tests(More)
We present a real-time, Linux-based testbed called LITMUS RT , which we have developed for empirically evaluating multiprocessor real-time scheduling algorithms. We also present the results from such an evaluation, in which partitioned earliest-deadline-first (EDF) scheduling, pre-emptive and nonpreemptive global EDF scheduling, and two variants of the(More)