Showing papers by "Lars Lundberg published in 2008"

Slack-based global multiprocessor scheduling of aperiodic tasks in parallel embedded real-time systems

Abstract: We provide a constant time schedulability test and priority assignment algorithm for an on-line multiprocessor server handling aperiodic tasks. Dhall's effect is avoided by dividing tasks in two priority classes based on their utilization: heavy and light. The improvement in this paper is due to assigning priority of light tasks based on slack - not on deadlines. We prove that if the load on the multiprocessor stays below (3 - radic5)/2 ap 38.197%, the server can accept an incoming aperiodic task and guarantee that the deadlines of all accepted tasks will be met. This is better than the current state-of- the-art algorithm where the priorities of light tasks are based on deadlines (the corresponding bound is in that case 35.425%).

Middleware Support for Performance Improvement of MABS Applications in the Grid Environment

Abstract: The computational Grid is an infrastructure which enables the execution of applications demanding huge computing resources. Hence, it can be the right environment for large-scale Multi-agent based simulation (MABS) applications. However, due to the nature of the Grid and the characteristics of MABS, achieving optimum performance poses a great challenge. Performance study of MABS applications is therefore a necessary undertaking which requires an understanding of these characteristics and the extent of their influence. Moreover, owing to the dynamicity and heterogeneity of the Grid, it is difficult to achieve performance gains without a middleware support for application deployment and dynamic reconfiguration. This paper presents a study of the key features of MABS applications that affect performance and proposes a supportive middleware to MABS platforms. Experiments show that the proposed middleware can bring performance improvement for MABS applications on the Grid.

Quality of Experience Based Cross-Layer Design of Mobile Video Systems

Abstract: This paper introduces and discusses quality of experience based cross-layer design of mobile video systems as a means of providing technologies for jointly analyzing, adopting, and optimizing system quality. The many benefits of our novel approaches over traditional concepts will range from efficient video processing techniques over advanced real-time scheduling algorithms, to networking and service level management techniques. This will lead to better service quality and resource utilization in mobile video systems.

Optimizations in the Cibyl binary translator for J2ME devices

Abstract: The Java J2ME platform is one of the largest software platforms available, and often the only available development platform for mobile phones, which is a problem when porting C or C++ applications. The Cibyl binary translator targets this problem, translating MIPS binaries into Java bytecode to run on J2ME devices. This paper presents the optimization framework used by Cibyl to provide compact and well-performing translated code. Cibyl optimizes expensive multiplications/divisions, floating point support, function co-location to Java methods and provides a peephole optimizer. The paper also evaluates Cibyl performance both in a real-world GPS navigation application where the optimizations increase display update frequency with around 15% and a comparison against native Java and the NestedVM binary translator where we show that Cibyl can provide significant advantages for common code patterns.