When quoting this document, please refer to the following
DOI: 10.4230/OASIcs.WCET.2008.1666
URN: urn:nbn:de:0030-drops-16666
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Whitham, Jack ; Audsley, Neil

Traces as a Solution to Pessimism and Modeling Costs in WCET Analysis

WhithamJack.Paper.1666.pdf (0.1 MB)


WCET analysis models for superscalar out-of-order CPUs generally need to be pessimistic in order to account for a wide range of possible dynamic behavior. CPU hardware modifications could be used to constrain operations to known execution paths called traces, permitting exploitation of instruction level parallelism with guaranteed timing. Previous implementations of traces have used microcode to constrain operations, but other possibilities exist. A new implementation strategy (virtual traces) is introduced here. In this paper the benefits and costs of traces are discussed. Advantages of traces include a reduction in pessimism in WCET analysis, with the need to accurately model CPU internals removed. Disadvantages of traces include a reduction of peak throughput of the CPU, a need for deterministic memory and a potential increase in the complexity of WCET models.

BibTeX - Entry

  author =	{Jack Whitham and Neil Audsley},
  title =	{{Traces as a Solution to Pessimism and Modeling Costs in WCET Analysis}},
  booktitle =	{8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
  series =	{OpenAccess Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-10-1},
  ISSN =	{2190-6807},
  year =	{2008},
  volume =	{8},
  editor =	{Raimund Kirner},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-16666},
  doi =		{10.4230/OASIcs.WCET.2008.1666},
  note =	{also published in print by Austrian Computer Society (OCG) with ISBN 978-3-85403-237-3},
  annote =	{Keywords: WCET superscalar cpu virtual traces}

Keywords: WCET superscalar cpu virtual traces
Seminar: 8th International Workshop on Worst-Case Execution Time WCET Analysis (WCET'08)
Issue Date: 2008
Date of publication: 13.11.2008

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