Simulation Model WCET Analysis with Composite Blocks and Path Filtering
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Solution Overview
Problem
Existing methods for determining Worst Case Execution Time (WCET) in simulation models are often inaccurate and inefficient, leading to potential failures in safety-critical systems due to pessimistic timing estimates and the inability to identify the most critical execution paths.
Innovation Solution
A system and method that generates an in-memory intermediate representation of the simulation model, constructs composite code blocks, and performs dynamic analysis on target hardware to accurately determine WCET by combining basic code blocks and instrumenting them for execution time measurement, while also conducting static path analysis to identify all possible execution paths and eliminate infeasible paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods are used to determine WCET in simulation models, then the analysis can be performed, but the accuracy of timing estimates deteriorates due to pessimistic estimates
Solution Approach 1:
The patent segments the simulation model into composite code blocks that can be individually analyzed. By dividing the model into manageable segments with defined entry and exit points, the system can measure execution time for each segment separately and aggregate results to determine overall WCET, avoiding the pessimistic estimates that come from analyzing the entire model as a single unit.
Solution Approach 2:
The patent introduces composite code blocks as intermediary structures between the simulation model and the WCET analysis process. These blocks serve as measurement points that capture execution time data without interfering with the normal simulation execution, enabling accurate timing measurements while maintaining system reliability.
2Measurement precision
If comprehensive WCET analysis is performed on all execution paths, then complete coverage is achieved, but the computational complexity increases significantly
Solution Approach 1:
The patent performs preliminary static analysis to identify and eliminate infeasible execution paths before conducting dynamic WCET measurement. By pre-processing the simulation model to remove paths that cannot be executed, the system reduces the computational complexity of subsequent analysis while maintaining complete coverage of all feasible execution paths.
Solution Approach 2:
The patent focuses WCET measurement efforts on critical execution paths that actually contribute to the worst-case scenario, rather than uniformly analyzing all possible paths. This selective approach achieves sufficient measurement precision for safety-critical systems without the excessive computational complexity of exhaustive path analysis.
3Ease of manufacture
If manual annotation methods are used for WCET analysis, then the process is simple to implement, but the accuracy deteriorates due to human error
Solution Approach 1:
The patent implements automated WCET analysis that performs static path analysis and dynamic measurement without requiring manual annotation by users. The system automatically instruments the composite code blocks, collects execution time data during simulation runs, and computes WCET results, eliminating human error while maintaining ease of implementation through automated tooling.
Solution Approach 2:
The patent replaces the manual mechanical process of annotation with an automated computational system. Instead of users manually marking critical paths and estimating execution times, the system uses algorithmic static analysis and automated dynamic measurement to determine WCET, significantly improving measurement precision while keeping the process accessible to users.
4Reliability
If resource allocation is based on pessimistic WCET estimates, then safety margins are ensured, but resource expenditure increases unnecessarily
Solution Approach 1:
The patent changes the WCET parameter from pessimistic estimates to tightly-bound accurate measurements by implementing automated static and dynamic analysis. This allows system designers to allocate resources based on actual worst-case execution times rather than conservative estimates, ensuring safety margins are maintained while eliminating unnecessary resource expenditure in non-critical areas.
Data Source
AI summary
Systems and methods determine tight Worst Case Execution Time (WCET) for a simulation model or code generated for a model. Composite code blocks may be constructed from basic code blocks of an in-memory representation of the model. Information on the model and its elements may be obtained and utilized to construct the composite code blocks. The composite code blocks may be instrumented and execution times may be measured for the composite code blocks. The execution times for the composite code blocks along paths through the model may be summed and the highest total execution time may be presented as the WCET for the model and/or the code generated for the model.