aiT: Accurate Worst-Case Execution Time Analysis for Real-Time Embedded Systems

As embedded systems become more complex and safety requirements more stringent, determining the worst-case execution time (WCET) of tasks is crucial. For industries such as aerospace, automotive, medical, and industrial automation—where software behavior must be deterministic and dependable—traditional measurement-based timing methods are no longer sufficient. Enter aiT, AbsInt’s powerful WCET analyzer that sets the standard for safe and precise timing validation in real-time systems.

Developed to meet the highest levels of functional safety, aiT computes tight and safe upper bounds for the execution time of tasks, considering the processor’s intricate hardware behavior, such as cache and pipeline effects, without requiring any modification to source code or compilation toolchain.

The Problem: Why Traditional Timing Analysis Falls Short

Many organizations still rely on measurement and testing to estimate task runtimes. However, these techniques are fundamentally limited:

• Incompleteness: It is nearly impossible to design test cases that cover all possible program paths and inputs, especially in systems with interrupts, branches, or dynamic behavior.
• Unsafe assumptions: Even if a task performs well in tests, there is no guarantee that it won’t take longer under different conditions.
• Measurement overhead: Instrumentation can distort execution timing, introducing variations that reduce the accuracy of the results.
• Hardware complexity: Modern microcontrollers feature pipelines, branch prediction, instruction and data caches, and out-of-order execution. Ignoring these components results in large overestimations—or worse, missed timing violations.

For hard real-time systems, these limitations are unacceptable. This is where aiT makes a critical difference.

aiT’s Solution: Safe, Precise, and Scalable Static Timing Analysis

aiT analyzes binary executables directly, modeling the exact timing behavior of the code on specific target hardware. The results are sound—meaning the computed WCET bounds are guaranteed to hold across all inputs and all execution paths—eliminating the need for exhaustive testing.

Key benefits of aiT include:

• No instrumentation or source changes: aiT analyzes the final, compiled executable, preserving true execution behavior.
• Precise modeling of hardware behavior: Instruction pipelines, cache hierarchies, branch prediction units, and other complex architectural features are fully accounted for.
• Tight bounds: By avoiding conservative assumptions and overestimation, aiT provides WCET estimates that closely reflect actual system performance.
• Support for numerous processors: aiT supports a wide range of architectures including PowerPC, ARM Cortex-M/R, TriCore, LEON, V850, Infineon, and more. Qualification support is also available for adding new targets.

Advanced Features for Engineers and Safety Experts

aiT is more than just an analysis tool—it's a full-featured platform for real-time timing diagnostics and optimization.

• Call and Control Flow Visualization: aiT graphically displays the control and call flow graphs of the analyzed application, including the critical path and per-function timing contributions. Developers can quickly identify performance bottlenecks or potential optimization areas.
• Machine State Inspection: aiT allows in-depth analysis of machine states at different program points, offering insight into the precise cause of timing anomalies.
• Qualification Support Kits (QSK): To ease compliance with industry standards like DO-178C, ISO 26262, and IEC 61508, aiT comes with qualification documentation and tools. It has already been successfully qualified up to the highest criticality levels, including DO-178B Level A.
• Annotations and User Knowledge Integration: Developers can provide manual annotations, such as loop bounds or recursion limits, to further improve the analysis accuracy while maintaining automation.
• Open XML-Based Interface: aiT integrates seamlessly with model-based code generators and system-level tools, enabling design-phase timing validation and schedulability analysis.
• Comparative Analysis Tools: aiT allows graphical comparison of different analysis runs, helping developers quickly understand the timing implications of code changes or hardware configuration adjustments.

Why aiT Matters

In real-time systems—especially those driven by event or time-triggered architectures like RMA, TTA, or FlexRay—the WCET of every task must be known before deployment. aiT enables this certainty by providing safe and precise execution time bounds.

With the increasing performance of embedded hardware, software complexity is growing rapidly. Often, tasks interact in unforeseen ways, and exhaustive input testing becomes impractical. aiT provides the only scalable and safe solution to timing validation in this context.

Whether you are working on a flight control computer, an automotive ECU, or an industrial robot, aiT ensures that your tasks will meet their deadlines—without requiring overly conservative resource margins or risking non-compliance.

Conclusion: aiT Enables Predictable Performance in an Unpredictable World

aiT from AbsInt empowers developers, integrators, and safety engineers to eliminate timing uncertainty in embedded systems. By analyzing real hardware behavior at the binary level and providing precise, sound WCET estimates, aiT eliminates the guesswork and risk from real-time performance engineering.

With its proven accuracy, broad processor support, qualification readiness, and powerful analysis capabilities, aiT is the leading solution for ensuring that your real-time applications not only function—but function on time.