Deferred Assignment Scheduling in Cluster-Based Servers

Abstract

This paper proposes a new scheduling policy for cluster-based servers called DAS (Deferred Assignment Scheduling). The main idea in DAS is to defer scheduling as much as possible in order to make better use of the accumulated information on job sizes. In broad outline, DAS operates as follows: (1) incoming jobs are held by the dispatcher in a buffer; (2) the dispatcher monitors the number of jobs being processed by each server; (3) when the number of jobs at a server queue drops below a prescribed threshold, the dispatcher sends to it the shortest job in its buffer.To gauge the efficacy of DAS, the paper presents simulation studies, using various data traces. The studies collected response times and slowdowns for two cluster configurations under multi-threaded and multi-process back-end server architectures. The experimental results show that in both architectures, DAS outperforms the Round-Robin policy in all traffic regimes, and the JSQ (Join Shortest Queue) policy in medium and heavy traffic regimes.

Multi-Criteria Job Scheduling in Grid Using an Accelerated Genetic Algorithm

“…In addition, in this work we consider a heterogeneous computational Grid, instead of a homogeneous as we have studied in [16]. Deferred Policy is also studied in [17,19,20]. When Grid Scheduler (GS) makes a decision about the cluster, where the jobs will be dispatched, jobs depart from the GS's queue and arrive at the Local Scheduler (LS) of the cluster.…”

Multi-layered round robin routing for parallel servers

“…Although a straightforward extension of [16], to our knowledge this result has not appeared in the literature. For example, Ungureanu et al [18] proposed that non-preemptive c-SRPT be used (they called this Deferred Assignment Scheduling (DAS)) and showed its effectiveness via simulation. Note that preemption is crucial in the optimality proof, the point here is that it is surprising that the optimality of c-SRPT was not used as motivation for DAS.…”

“…For c-SRPT, if there are only type k or higher jobs in the system, each server is processing a type k job (if there are at least c type k jobs in the system, if not, each type k job in the system is processed by a server). A similar routing policy has been suggested by Ungureanu et al [19] called Class Dependent Assignment (CDA), in which "short" jobs are assigned in a round robin manner and "long" jobs are deferred until servers become idle. However, processing at a server is FCFS.…”

Chemical Reaction Optimization for Task Scheduling in Grid Computing

“…Also, the system can process the tasks in batches or handle a task immediately once submitted. Other policies like Deferred Assignment Scheduling (DAS) [23], [24] are adopted by some researchers as well. Moreover, tasks can also be independent or have precedence relationship.…”