31 research outputs found
Using dynamic, full cache locking and genetic algorithms for cache size minimization in multitasking, preemptive, real-time systems
The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-45008-2_13Cache locking have shown during the last years their usefulness easing the schedulability analysis of multitasking, preemptive, real-time systems. Cache locking provides a high degree of predictability while system performance is maintained at a similar level to that provided by regular, highly unpredictable, non-locked cache. Cache locking may also be useful to reduce hardware costs by means of reducing the size of the cache memory needed to make a real-time system schedulable.This work shows how full, dynamic cache locking may help to reduce the size of the cache memory versus a regular cache. This reduction is possible thanks to a genetic algorithm that selects the set of instructions that have to be locked in cache to provide the maximum cache size minimization while keeping the system schedulable.This work is partially supported by PAID-06-11/2055 of Universitat Politècnica de València and TIN2011-28435-C03-01 of Ministerio de Ciencia e Innovación.Martà Campoy, A.; RodrÃguez Ballester, F.; Ors Carot, R. (2013). Using dynamic, full cache locking and genetic algorithms for cache size minimization in multitasking, preemptive, real-time systems. En Theory and Practice of Natural Computing. Springer Verlag (Germany). 157-168. https://doi.org/10.1007/978-3-642-45008-2S15716
Towards best-case response times of real-time tasks under fixed-priority scheduling with deferred preemption
In this paper, we present lower bounds for best-case response times of periodic tasks under fixed-priority scheduling with deferred preemption (FPDS) and arbitrary phasing. Our analysis is based on a dedicated conjecture for a ¿-optimal instant, and uses the notion of best-case occupied time. We briefly compare best-case analysis and worst-case analysis for FPDS and arbitrary phasing
HADES: A Middleware Support for Distributed Safety-Critical Real-Time Applications
Most distributed safety-critical real-time systems designed in the past have been specialized to meet the particular requirements of the application domain to which they were targeted. This approach led to specific, inflexible, dedicated and non-reusable solutions, often based on specialized hardware. This paper presents an overview of hades, which provides a set of flexible tools built on top of off-the-shelf hardware, and designed to help in the construction of a panel of distributed safety-critical real-time applications. In order for hades to support the execution of the widest range of applications, we have followed a rigorous methodology based on (i) the separation of services dedicated to a specific application domain (scheduling policy) from services providing a range of robustness properties common to a large spectrum of application domains (e.g. task dispatching, fault detection, clock synchronization, monitoring); (ii) the provision of a precise cost information induced by a..