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Analysis of preemptively scheduled hard real-time systems

© INRIA Sophie Auvin - A comme Algorithme

Sebastian Altmeyer is a post-doctoral researcher in the Computer Systems Architecture Group at the University of Amsterdam, Netherlands since 2013. He has received his PhD in Computer Science in 2012 from Saarland University in Saarbruecken, Germany with a thesis on the analysis of pre-emptively scheduled hard real-time systems.  His research interests are the analysis and verification of hard real-time systems in general, with a particular focus on worst-case timing analysis and real-time scheduling.

  • Date : 8/12/2014
  • Place : Inria Paris-Rocquencourt, building 9
  • Guest(s) : Sebastian Altmeyer (University of Amsterdam)

As timing is a major property of hard real-time systems, proving timing correctness is  of utter importance. Traditionally, a static timing analysis derives upper bounds on the  execution time of tasks and a scheduling analysis then uses these bounds and checks if  each task meets its timing constraints.

In preemptively scheduled systems with caches, this interface between timing analysis and scheduling analysis must be  considered outdated. On a context switch, a preempting task may evict cached  data of a preempted task that need to be reloaded again after preemption. The  additional execution time due to these reloads, called cache-related  preemption delay (CRPD), may substantially prolong a task's execution time and  strongly influence the system's performance.

In this talk, I will present the analysis to bound the cache-related preemption delay, discuss the applicability and the limitations of a separate CRPD computation and show how to account for the CRPD within the schedulability analysis for fixed-priority preemptive systems.

Keywords: Séminaire Aoste Analysis Preemptively Scheduled Hard real-time Systems