Special Cases of Online Parallel Job Scheduling
نویسندگان
چکیده
In this paper we consider the online scheduling of jobs, which require processing on a number of machines simultaneously. These jobs are presented to a decision maker one by one, where the next job becomes known as soon as the current job is scheduled. The objective is to minimize the makespan. For the problem with three machines we give a 2.8-competitive algorithm, improving upon the 3-competitive greedy algorithm. For the special case with arbitrary number of machines, where the jobs appear in non-increasing order of machine requirement, we give a 2.4815-competitive algorithm, improving the 2.75-competitive greedy algorithm.
منابع مشابه
Online Algorithms for a Generalized Parallel Machine Scheduling Problem
We consider different online algorithms for a generalized scheduling problem for parallel machines, described in details in the first section. This problem is the generalization of the classical parallel machine scheduling problem, when the makespan is minimized; in that case each job contains only one task. On the other hand, the problem in consideration is still a special version of the workf...
متن کاملOnline Algorithm for Parallel Job Scheduling and Strip Packing
We consider the online scheduling problem of parallel jobs on parallel machines, P |online − list,mj |Cmax. For this problem we present a 6.6623-competitive algorithm. This improves the best known 7competitive algorithm for this problem. The presented algorithm also applies to the special case where machines are ordered on a line and only adjacent machines can be assigned to a job and, therefor...
متن کاملOn-line scheduling of two parallel machines with a single server
In this paper, we consider the on-line scheduling of two parallel identical machines sharing a single server with the objective of minimizing the latest completion time of all jobs. Each job has to be setup by the server before being processed on one of the machines. Three special cases: equal length jobs, equal processing times and regular equal setup times are considered and the asymptotic co...
متن کاملOnline Scheduling & Project Scheduling
This thesis presents new and improved scheduling algorithms for a number of scheduling problems. The first part of the thesis deals with two online-list scheduling problems, both with the objective to minimize the makespan. In these problems, the jobs arrive one by one and the decision maker has to irrevocably schedule the arriving job before the next job becomes known. In the second part, a ne...
متن کاملOn-line scheduling of parallel jobs in a list
We study an on-line parallel job scheduling problem, where jobs arrive one by one. A parallel job may require a number of machines for its processing at the same time. Upon arrival of a job, its processing time and the number of requested machines become known, and it must be scheduled immediately without any knowledge of future jobs. We present a 7-competitive on-line algorithm, which improves...
متن کامل