License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ECRTS.2018.13
URN: urn:nbn:de:0030-drops-89904
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Freitag, Johannes ; Uhrig, Sascha ; Ungerer, Theo

Virtual Timing Isolation for Mixed-Criticality Systems

LIPIcs-ECRTS-2018-13.pdf (0.8 MB)


Commercial of the shelf multicore processors suffer from timing interferences between cores which complicates applying them in hard real-time systems like avionic applications. This paper proposes a virtual timing isolation of one main application running on one core from all other cores. The proposed technique is based on hardware external to the multicore processor and completely transparent to the main application i.e., no modifications of the software including the operating system are necessary. The basic idea is to apply a single-core execution based Worst Case Execution Time analysis and to accept a predefined slowdown during multicore execution. If the slowdown exceeds the acceptable bounds, interferences will be reduced by controlling the behavior of low-critical cores to keep the main application's progress inside the given bounds. Apart from the main goal of isolating the timing of the critical application a subgoal is also to efficiently use the other cores. For that purpose, three different mechanisms for controlling the non-critical cores are compared regarding efficient usage of the complete processor.
Measuring the progress of the main application is performed by tracking the application's Fingerprint. This technology quantifies online any slowdown of execution compared to a given baseline (single-core execution). Several countermeasures to compensate unacceptable slowdowns are proposed and evaluated in this paper, together with an accuracy evaluation of the Fingerprinting. Our evaluations using the TACLeBench benchmark suite show that we can meet a given acceptable timing bound of 4 percent slowdown with a resulting real slowdown of only 3.27 percent in case of a pulse width modulated control and of 4.44 percent in the case of a frequency scaling control.

BibTeX - Entry

  author =	{Johannes Freitag and Sascha Uhrig and Theo Ungerer},
  title =	{{Virtual Timing Isolation for Mixed-Criticality Systems}},
  booktitle =	{30th Euromicro Conference on Real-Time Systems (ECRTS 2018)},
  pages =	{13:1--13:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-075-0},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{106},
  editor =	{Sebastian Altmeyer},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-89904},
  doi =		{10.4230/LIPIcs.ECRTS.2018.13},
  annote =	{Keywords: multicore, hard real-time systems, timing isolation, safety-critical systems, mixed-criticality design and assurance}

Keywords: multicore, hard real-time systems, timing isolation, safety-critical systems, mixed-criticality design and assurance
Collection: 30th Euromicro Conference on Real-Time Systems (ECRTS 2018)
Issue Date: 2018
Date of publication: 22.06.2018

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