WCET and Stack analysis

WCET (Worst Case Execution Time) and Stack analysis were identified in DO-178B/ED-12B as part of reviews and analysis of the source code verification process (objective “accuracy and consistency” in 6.3.4.f). But time and memory assessment might not be achieved only through reviews and analysis of source code.

Limited additions were made to try to address this concern.

  • In §6.3.4.f, a sentence is added, requiring that compiler, linker and hardware be assessed for impact on WCET.
  • In the introduction to the section on software reviews and analysis (§6.3), it is also identified that reviews and analysis alone may not completely satisfy some objectives (e.g. WCET, stack analysis) and that some tests may be also necessary.

The FAQ#73Are timing measurements during testing sufficient or is a rigorous demonstration of worst-case timing necessary?was reworked to provide a complete discussion of this topic, but the revision was editorial in nature and doesn’t provide additional information.