Hybrid worst-case timing analysis

TimeWeaver combines static analysis with non-intrusive measurements to provide worst-case execution time estimates.

The tool estimates the worst-case execution time (WCET) of tasks based on the exe­cution time of trace segments obtained from real-time instruction-level tracing. The computed time bounds are valuable for soft real-time systems and provide feedback for optimizing worst-case performance.

Your benefits

• The hybrid approach works for a wide range of modern high-performance processors that are not statically predictable anymore, not even by a most sophisticated tool such as aiT. This includes multi-core processors where inter-core interferences cannot be prevented or controlled in a satisfactory way, or where the available documentation is insufficient to build a static timing model.
• TimeWeaver is non-intrusive. It needs no code instrumentation that distorts timing measurements. It uses the embedded trace units of modern embedded processors (Nexus 5001, CoreSight ETM, etc.) to observe program flow. Interference effects included in the traces, such as access delays to shared resources, are taken into account. This approach is compliant with the recommendations of CAST (CAST-32A) and EASA (AMC 20-193).

Workflow

TimeWeaver takes as input:

1. a binary executable
2. execution traces,
   e.g. BHM traces compliant to the IEEE-ISTO 5001 standard
3. optional user annotations,
   e.g. on loop bounds, in the same format as other AbsInt analyzers such as aiT or StackAnalyzer

TimeWeaver then provides a safe upper bound of the length of the longest execution path, based on the local time measurements in the traces.

Features

The analysis results reported by TimeWeaver include:

• global end-to-end time, based on the maximum observed trace segment times combined to an overall bound
• end-to-end bounds for specific functions, depending on trace points
• coverage of the control-flow graph by the input traces
• maximum possible and maximum observed iteration counts for loops
• time variance of each code segment over all traces

TimeWeaver offers the same powerful user interface you are used to from working with other AbsInt tools, with fully integrated graphical and textual viewers for control flow, analysis results, source code, assembly code, and configuration files. You can:

• interactively explore analysis results
• save, restore, and compare analysis scenarios
• export customizable reports for documentation and certification purposes
• start all analyses from the same GUI and handle all the tools with the same look and feel

Qualification support

Your usage of TimeWeaver can be qualified according to ISO 26262, DO-178B/C, and other safety standards. We offer special Qualification Support Kits that help you simplify and automate your qualification process.

Supported targets and compilers

TimeWeaver is available for a growing variety of processors and compilers.

Free 30-day trial

Request your free trial package today, complete with free training and support.