Rami G. Melhem

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In this paper, we address power-aware scheduling of periodic hard real-time tasks using dynamic voltage scaling. Our solution includes three parts: (a) a static (off-line) solution to compute the optimal speed, assuming worst-case workload for each arrival, (b) an on-line speed reduction mechanism to reclaim energy by adapting to the actual workload, and(More)
The slack time in real-time systems can be used by recovery schemes to increase system reliability as well as by frequency and voltage scaling techniques to save energy. Moreover, the rate of transient faults (i.e., soft errors caused, for example, by cosmic ray radiations) also depends on system operating frequency and supply voltage. Thus, there is an(More)
The power consumption of modern high-performance processors is becoming a major concern because it leads to increased heat dissipation and decreased reliability. While many techniques have been proposed to reduce power consumption for uni-processors, there has been considerably less work on multi-processor systems. In this paper, we focus on poweraware(More)
In this paper, we provide an efficient solution for periodic real-time tasks with (potentially) different power consumption characteristics. We show that, a task T, can run a t a constant speed 5';. at every instance without hurting optimality. We sketch an O(n2 log n) algorithm to compute the optimal S;. values. We also prove that the EDF (Earliest(More)
Real-time systems are being increasingly used in several applications which are time critical in nature. Fault-tolerance is an important requirement of such systems, due to the catastrophic consequences of not tolerating faults. In this paper, we study a scheme that provides fault-tolerance through scheduling in real-time multiprocessor systems. We schedule(More)
The introduction of Phase-Change Memory (PCM) as a main memory technology has great potential to achieve a large energy reduction. PCM has desirable energy and scalability properties, but its use for main memory also poses challenges such as limited write endurance with at most 10<sup>7</sup> writes per bit cell before failure. This paper describes(More)
This paper describes how to exploit the scheduling slack in a real-time system to reduce energy consumption and achieve fault tolerance at the same time. During failure-free operation, a task takes checkpoints to enable recovery from failure. Additionally, the system exploits the slack to conserve energy by reducing the processor speed. If a task fails, it(More)
An optical communication structure for multiprocessor arrays that exploits the high communication bahdwidth of optical waveguides is proposed. The structutje takes advantage of two properties of optical signal tr~nsmissions on waveguides. Namely, unidirectional pfjpagation and predictable propagation delays per unit lehgth. Two novel time-division(More)
A real-time system must execute functionally correct computations in a timely manner. In order to guarantee that all tasks accepted in the system will meet their timing requirements, an admission control algorithm must be used to only accept tasks whose requirements can be satisfied. Rate-monotonic scheduling (RMS) is arguably the best known scheduling(More)