On-Line Hard Real-Time Scheduling of Parallel Tasks on Partitionable Multiprocessors

Abstract

Until now little research has addressed the problem of on line scheduling of sporadic parallel tasks with hard deadlines in partitionable multiprocessor sys tems In this paper we present two on-line scheduling al gorithms -Buddy/RTand Stacking, for such environments Both the algorithms either guarantee or reject a task at the time of its arrival Buddy/RT is a straight-forward extension of the well-known Buddy strategy to the real time environment, while Stacking is a more sophisticated algorithm based on the lessons learned from Buddy/RT The underlying concept behind the Stacking algorithm is to reduce fragmentation by 'stacking' equal-sized jobs in the time dimension The Stacking algorithm is found to perform significantly better than Buddy/RT over a wide range of workloads, even though both the algorithms have the same time complexity

Dynamic Real-Time Task Scheduling on Hypercubes

“…Job miss ratio and work miss ratio are two parameters that are used as performance measures for the real-time scheduling algorithms. The results indicate that the proposed DEDF algorithm has a significantly lower job/ work miss ratio than the previously proposed Buddy/RT and Stacking algorithms [1].…”

“…The Buddy/RT processor allocation algorithm for real-time systems proposed by Babbar and Krueger [1] is an extension of the buddy scheme proposed earlier for memory systems [12] and processor allocations [3]. The basic idea of the scheme is to include an additional restriction-time-while doing allocation.…”

“…The characteristics of the aperiodic tasks are not known a priori and the scheduling decisions are made upon their arrival. Thus arises the need for on-line or dynamic 1 This research was supported in part by the National Science Foundation under Grants MIP-9628801 and CCR-9634547. A preliminary version of this paper was presented at the Symposium of Parallel and Distributed Processing, 1996. scheduling of tasks.…”

Scheduling best-effort and real-time pipelined applications on time-shared clusters

“…Proportional allocation of resources to a mixture of jobs with periodic deadlines has also been studied [27]. There has also been prior work on scheduling parallel real-time workloads [4,11,18].…”

Políticas de escalonamento de tempo-real para garantia de QoS absoluta em array de servidores web heterogêneos

“…Para um sistema comúnico processador, foi mostrado que os algoritmos EDF e o LLF (Least Laxity First ) (Liu & Layland, 1973) (Stankovic et al, 1995) possuem bons resultados em condições normais de uso dos recursos existentes. Entretanto, em sistemas multiprocessados, o escalonamento em tempo-realé NP-difícil (Liebeherr et al, 1995) (Liu & Layland, 1973) ) (Stankovic et al, 1998) (Ghosal et al, 1991) (Babbar & Krueger, 1994).…”