Task Activity Vectors: A Novel Metric for Temperature-Aware and Energy-Efficient Scheduling

This thesis introduces the abstraction of the task activity vector to characterize applications by the processor resources they utilize. Based on activity vectors, the thesis introduces scheduling policies for improving the temperature distribution on the processor chip and for increasing energy efficiency by reducing the contention for shared resources of multicore and multithreaded processors

Concurrent processing adaptation of aeroplastic analysis of propfans

Discussed here is a study involving the adaptation of an advanced aeroelastic analysis program to run concurrently on a shared memory multiple processor computer. The program uses a three-dimensional compressible unsteady aerodynamic model and blade normal modes to calculate aeroelastic stability and response of propfan blades. The identification of the computational parallelism within the sequential code and the scheduling of the concurrent subtasks to minimize processor idle time are discussed. Processor idle time in the calculation of the unsteady aerodynamic coefficients was reduced by the simple strategy of appropriately ordering the computations. Speedup and efficiency results are presented for the calculation of the matched flutter point of an experimental propfan model. The results show that efficiencies above 70 percent can be obtained using the present implementation with 7 processors. The parallel computational strategy described here is also applicable to other aeroelastic analysis procedures based on panel methods

Robust Partitioned Scheduling for Static-Priority Real-Time Multiprocessor Systems with Shared Resources

International audienceWe focus on the partitioned scheduling of sporadic real-time tasks with constrained deadlines. The scheduling policy on each processor is static-priority. The considered tasks are not independent and the consistency of these shared data is ensured by a multiprocessor synchronization protocol. Considering these assumptions, we propose a partitioned scheduling algorithm which tends to maximize the robustness of the tasks to the Worst Case Execution Time (WCET) overruns faults. We describe the context of the problem and we outline our solution based on simulated annealing

A Survey of Research into Mixed Criticality Systems

This survey covers research into mixed criticality systems that has been published since Vestal’s seminal paper in 2007, up until the end of 2016. The survey is organised along the lines of the major research areas within this topic. These include single processor analysis (including fixed priority and EDF scheduling, shared resources and static and synchronous scheduling), multiprocessor analysis, realistic models, and systems issues. The survey also explores the relationship between research into mixed criticality systems and other topics such as hard and soft time constraints, fault tolerant scheduling, hierarchical scheduling, cyber physical systems, probabilistic real-time systems, and industrial safety standards

Truthful Mechanisms For Real-Time System Scheduling In Competitive Environments

In a non-competitive environment, sporadic real-time task scheduling on a single processor is well understood. In this thesis, we consider a competitive environment comprising several real-time tasks vying for execution upon a shared single processor. Each task obtains a value if the processor successfully schedules all its jobs. Our objective is to select a feasible subset of these tasks to maximize the sum of values of selected tasks. We consider both dynamic-priority and static-priority scheduling algorithms. There are algorithms for solving these problems in non-competitive settings. However, we consider these problems in an economic setting in which each task is owned by a selfish agent. Each agent reports the characteristics of her own task to the processor owner. The processor owner uses a mechanism to allocate the processor to a subset of agents and to determine the payment of each agent. Since agents are selfish, they may try to manipulate the mechanism to obtain the processor. We are interested in truthful mechanisms in which it is always in agents\u27 best interest to report the true characteristics of their tasks. We design exact and approximate truthful mechanisms for this competitive environment and study their performance