We are given a set of jobs, each one specified by its release date, its deadline and its processing volume (work), and a single (or a set of) speed-scalable processor(s). We adopt the standard model in speed-scaling in which if a processor runs at speed s then the energy consumption is s units of energy per time unit, where α > 1 is a small constant. Our goal is to find a schedule respecting th...

The relative worst order ratio is a measure for the quality of online algorithms. Unlike the competitive ratio, it compares algorithms directly without involving an optimal offline algorithm. The measure has been successfully applied to problems like paging and bin packing. In this paper, we apply it to machine scheduling. We show that for preemptive scheduling, the measure separates multiple p...

in the directory /pub/techreports. Abstracts and compressed postscript files are available via Real-time, multi-tasking software, such as that used in embedded control systems, is notoriously difficult to develop and maintain. Scheduling theory offers a mathematically-sound way of predicting the timing behaviour of sets of communicating, concurrent tasks, but its principles are often unfamiliar...

We present a computer-aided programming approach to concurrency. The approach allows programmers to program assuming a friendly, non-preemptive scheduler, and our synthesis procedure inserts synchronization to ensure that the final program works even with a preemptive scheduler. The correctness specification is implicit, inferred from the non-preemptive behavior. Let us consider sequences of ca...

When a computer system schedules jobs there is typically significant cost associated with preempting job during execution. This can be incurred from the expensive task of saving memory’s state or loading data into and out memory. Thus, it desirable to schedule non-preemptively avoid costs preemption. There need for non-preemptive schedulers desktops, servers, centers. Despite this need, gap bet...

We design an algorithm of the best possible competitive ratio for preemptive and non-preemptive scheduling of unit size jobs with rejection on three identical machines. The algorithm does not use preemption even for the preemptive variant, and it has the interesting feature that one of its parameters is not fixed in advance, and it is defined based on the properties of the first input job havin...