We consider preemptive scheduling of N tasks on m processors; processors have different speeds, tasks require amounts of work which are exponentially distributed, with different parameters. The policies of assigning at every moment the task with shortest (longest) expected processing time among those not yet completed to the fastest processor available, second shortest (longest) to the second f...

Guaranteeing quality for differentiated services while ensuring resource efficiency is an important and yet challenging problem in large computing clusters. Priority scheduling is commonly adopted in production systems to minimize the response time of high-priority workload by means of preempting the execution of low-priority workload when faced with limited resources. As a result, the system p...

Parallel applications can be executed using the idle computing capacity of workstation clusters. However, it remains unclear how to most effectively schedule the processors among different applications. Processor scheduling algorithms that were successful for shared-memory machines have proven to be inadequate for distributed memory environments due to the high costs of remote memory accesses a...

In this paper we use competitive analysis to study preemptive multiprocessor allocation policies for parallel jobs whose execution time is not known to the scheduler at the time of scheduling. The objective is to minimize the makespan (i.e., the completion time of the last job to finish executing). We characterize a parallel job, Ji , by two parameters: its execution time, li , and its parallel...

We investigate the problem of on-line scheduling two-machine open shops with the objective of minimizing the makespan. Jobs arrive independently over time, and the existence of a job is not known until its arrival. In the clairvoyant on-line model, the processing requirement of every job becomes fully known at the arrival of the job, while in the non-clairvoyant on-line model, this processing r...

We consider scheduling on a single machine with one non-availability period to minimize the weighted sum of completion times. We provide a preemptive algorithm with an approximation ratio arbitrarily close to the Golden Ratio, (1+ √ 5)/2+ε, which improves on a previously best known 2approximation. The non-preemptive version of the same algorithm yields a (2 + ε)-approximation.

We consider a single machine earliness/tardiness scheduling problem with general weights, ready times and due dates. Using completion time information obtained from the optimal solution to a preemptive relaxation, we generate feasible solutions to the original non-preemptive problem. We report extensive computational results demonstrating the speed and effectiveness of this approach.

This paper reports on our on going empirical evalu ation of a two tiered resource allocation scheme assum ing independent jobs that is jobs have no precedence constraints The rst tier extends the temporal density approach load balancing within a time interval while the second tier uses variations of the Earliest Deadline First EDF approach to schedule jobs at a site However job scheduling at si...

This paper reports on our on going empirical evalu ation of a two tiered resource allocation scheme assum ing independent jobs that is jobs have no precedence constraints The rst tier extends the temporal density approach load balancing within a time interval while the second tier uses variations of the Earliest Deadline First EDF approach to schedule jobs at a site However job scheduling at si...

The embedded systems work on real time operating systems (ERTOS). There are many CPU scheduling policies in general operating systems out of which ERTOS most commonly follow the priority and round robin scheduling. The aim of this research work is to evaluate performance of these scheduling policies. Simulation is adopted as tool to find the best policy that can be implemented to boost the perf...