Static WCET Analysis of Real-Time Task-Oriented Code in Vehicle Control Systems

Abstract

Abstract. Methods for Worst-Case Execution Time (WCET) analysis have been known for some time, and recently commercial tools have emerged. This technique is gradually being entered into industry to analyse real production codes. This article presents a case study where the aiT WCET analysis tool was used to find upper time bounds for taskoriented vehicular control code. The main purpose was to investigate the practical difficulties that arise when applying the current WCET analysis methods to this particular kind of code. In particular, we were interested in how labor-intense the analysis becomes, measured by the number of manual annotations necessary for calculating a WCET estimate. We were also interested how much tighter WCET estimates will become by manually adding extra annotations, and how much additional work that is needed to give these annotations. We also made some systematic comparisons between calculated and measured WCET estimates for the analysed system.

Automatic Derivation of Loop Bounds and Infeasible Paths for WCET Analysis Using Abstract Execution

“…The next step is to try out the algorithms on industrial real-time codes. In a previous case study [20], we were able to obtain considerably better WCET estimates for some industrial real-time code by adding infeasible path constraints by hand. We plan to run our infeasible path analyses on the same code to see if we can derive these constraints automatically.…”

“…Recent industrial WCET case studies [3,7,20], have shown that it is important to develop good support for both loop bound and infeasible path analyses, thereby reducing the need for manual annotations.…”

Fault Diagnosis and Reconfiguration Method for Network-on-Chip Based Multiple Processor Systems with Restricted Private Memories

“…However, it is specifically assumed that network-on-chips can be used when the packet injection rate is low, i.e., the worst congestion does not occur. In addition, as mentioned in [38], hard real-time code often has a fairly simple control structure, with few loops, no recursion, and few dynamic features such as dynamic calls and memory allocations. Therefore, in this paper, it is assumed that the above formula is enough shorter than the deadline period.…”

Accurate Determination of Loop Iterations for Worst-Case Execution Time Analysis

“…A decade ago, Chapman [2] found that even for quite simple programs and simple hardware, 30% pessimism was not uncommon and in one case 64% pessimism was observed. More recently, an industrial case study [18] found pessimism of 4-33% when the aiT tool was used to analyse industrial code. This was approximately doubled if hand-coded annotations were not given.…”