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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)
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)
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)
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)
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)
Many embedded platforms consist of a heterogeneous collection of processing elements, memory modules, and communication subsystems. These components often implement different scheduling/arbitration policies, have different interfaces , and are supplied by different vendors. Hence, compositional techniques for modeling and analyzing such platforms are of(More)