Real-Time Systems

, Volume 48, Issue 5, pp 499–526 | Cite as

Improved cache related pre-emption delay aware response time analysis for fixed priority pre-emptive systems

  • Sebastian Altmeyer
  • Robert I. Davis
  • Claire Maiza


Without the use of caches the increasing gap between processor and memory speeds in modern embedded microprocessors would have resulted in memory access times becoming an unacceptable bottleneck. In such systems, cache related pre-emption delays can be a significant proportion of task execution times. To obtain tight bounds on the response times of tasks in pre-emptively scheduled systems, it is necessary to integrate worst-case execution time analysis and schedulability analysis via the use of an appropriate model of pre-emption costs.

In this paper, we introduce a new method of bounding pre-emption costs, called the ECB-Union approach. The ECB-Union approach complements an existing UCB-Union approach. We improve upon both of these approaches via the introduction of Multiset variants which reduce the amount of pessimism in the analysis. Further, we combine these Multiset approaches into a simple composite approach that dominates both. These approaches to bounding pre-emption costs are integrated into response time analysis for fixed priority pre-emptively scheduled systems. Further, we extend this analysis to systems where tasks can access resources in mutual exclusion, in the process resolving omissions in existing models of pre-emption delays. A case study and empirical evaluation demonstrate the effectiveness of the ECB-Union, Multiset and combined approaches for a wide range of different cache configurations including cache utilization, cache set size, reuse, and block reload times.


Fixed priority pre-emptive scheduling Cache related pre-emption delay Response time analysis 



This research and collaboration came about as a result of the 1st Real-Time Scheduling Open Problems Seminar (RTSOPS 2010) (see Altmeyer and Burguière 2010). This work was partially funded by the UK EPSRC funded Tempo project (EP/G055548/1), the Transregional Collaborative Research Center AVACS of the German Research Council (DFG) and the EU funded ArtistDesign Network of Excellence. We also like to thank Alan Burns, Jack Whitham and the anonymous reviewers for their comments on an earlier draft of this paper.


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Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Sebastian Altmeyer
    • 1
  • Robert I. Davis
    • 2
  • Claire Maiza
    • 3
  1. 1.Compiler Design LabSaarland UniversitySaarbrückenGermany
  2. 2.University of YorkYorkUK
  3. 3.VerimagINP GrenobleGrenobleFrance

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