Scheduling problems that involve distance constraint tasks with repetitive requests is becoming increasingly popular in real time systems. Timing constraints defined by periods of fixed lengths for each task enforce some frequency of task execution. Alternatively deadlines could be specified relatively to the finish time of the previous execution of the same task. Hence the scheduling algorithm...

We study classic machine sequencing problems in an online setting. Specifically, we look at deterministic and randomized algorithms for the problem of scheduling jobs with release dates on identical parallel machines, to minimize the sum of weighted completion times: Both preemptive and non-preemptive versions are analyzed. Using linear programming techniques, borrowed from the single machine c...

This paper is devoted to basic scheduling problems in which the scheduling cost of a job is not a function of its completion time. Instead, the cost is derived from the integration of a cost function over the time intervals on which the job is processed. This criterion is specially meaningful when job preemption is allowed. Polynomial algorithms are presented to solve some special cases includi...

The problem of online multiprocessor scheduling with rejection was introduced by Bartal, Leonardi, Marchetti-Spaccamela, Sgall and Stougie 4]. They show that for this problem the competitive ratio is 1 + 2:61803, where is the golden ratio. A modiied model of multipro-cessor scheduling with rejection is presented where preemption is allowed. For this model, it is shown that better performance is...

We consider online preemptive scheduling of jobs, arriving one by one, on m identical parallel machines. A buffer of a fixed size K > 0, which assists in partial reordering of the input, is available to be used for the storage of at most K unscheduled jobs. We study the effect of using a fixed sized buffer (of an arbitrary size) on the supremum competitive ratio over all numbers of machines (th...

This paper revisits basic message response time analysis of controller area network (CAN). We show that existing message response time analysis, as presented in [10], is optimistic. Assuming discrete scheduling, the problem can be resolved by applying worst-case response time analysis for fixed-priority non-preemptive scheduling (FPNS) as described in [4].

Three characteristics encountered frequently in real-world machine scheduling are jobs released over time, precedence constraints between jobs, and average performance optimization. The general constrained one-machine scheduling problem to minimize the average weighted completion time not only captures these features, but also is an important building block for more complex problems involving m...

Scheduling theory as it applies to hard real-time environments with precedence and strict periodicity constraints — environments where the failure to satisfy any constraint may have disastrous consequences [1], [2] — seems currently to be enjoying a renaissance. The most widely studied problems in this field concern periodic non-preemptive tasks for systems where data are collected throught cap...

Context switching times are a major source of overhead in medium to fine grain process scheduling. We compared three different context switching techniques for non-preemptive scheduling in context of hardware/software codesign, and found major differences in performance and code size efficiency.

CPU scheduling is the basis of multi programmed operating system. The idea of multiprogramming is relatively simple, if a process (job) is waiting for an I/O request, then CPU switches from one job to another job so that CPU is always busy and computer becomes more productive. Scheduling is a fundamental operating system function, almost all computer resources are scheduled before use. The CPU ...