Multi-Core Contention Mitigation via Stressful Application Simulation

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Solution Overview

Problem

Multi-master embedded platforms face challenges in achieving deterministic operation due to conflicts from concurrent access to shared resources, which is critical in high-reliability environments like avionics, where existing solutions either conceal issues or have physical limitations, making them unsuitable for high-criticality contexts.

Innovation Solution

A method for mitigating contentions in multi-core platforms by determining and executing stressful applications that simulate worst-case scenarios, allowing for predictable operation without oversizing components, using arbitration levels and software to manage access channels and interference channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multi-master architecture is used to enable parallel execution, then productivity is improved, but reliability deteriorates due to uncontrolled contention and non-deterministic operation

Engineering Contradiction:
Improveparallel execution capabilityVSAvoidoperational determinism
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing worst-case execution times for all possible contention scenarios before runtime. The arbitration mechanism uses these pre-computed values to make deterministic scheduling decisions, eliminating the need for runtime analysis and ensuring predictable behavior in multi-master environments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an arbitration level as an intermediary between cores and shared resources. This mediator implements a deterministic arbitration policy that fairly allocates access to shared resources, preventing contention-induced non-determinism while maintaining parallel execution capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If acceleration mechanisms are added to increase core performance, then productivity is improved, but device complexity increases and physical limits are reached

Engineering Contradiction:
Improvecore performanceVSAvoidarbitration and resource management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements self-service by enabling each core to independently calculate its worst-case execution time for shared resource access using a formal model. This self-computed information is then used by the arbitration mechanism, eliminating the need for complex centralized analysis tools or external verification infrastructure.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the parameter representation by using worst-case execution time values as explicit parameters in the arbitration decision-making process. This transformation of performance characteristics into discrete, comparable parameters simplifies the arbitration logic and reduces overall system complexity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If contention mitigation is implemented to ensure deterministic operation, then reliability is improved, but loss of time occurs due to arbitration overhead

Engineering Contradiction:
Improvedeterministic operationVSAvoidarbitration overhead
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating worst-case execution times during system configuration or initialization. These pre-computed values are stored and reused during runtime arbitration, eliminating the need for time-consuming runtime analysis and minimizing arbitration overhead.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If shared resources are used to enable multi-core execution, then productivity is improved, but harmful factors increase due to conflicts and uncontrolled access times

Engineering Contradiction:
Improvemulti-core execution capabilityVSAvoidcontention conflicts
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an arbitration level as an intermediary between cores and shared resources. This mediator implements a deterministic arbitration policy that fairly allocates access to shared resources, preventing contention-induced non-determinism while maintaining parallel execution capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements feedback by using worst-case execution time measurements from actual system operation to validate and refine the formal model. This feedback loop ensures that the contention mitigation mechanism adapts to real-world performance characteristics while maintaining deterministic guarantees.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3910914B1Method for mitigating restraints for an operational application, associated computer program product and method for determining a harmful application
Publication Date: 2024.09.04 THALES SA
  • EP3910914B1 patent drawingFigure 1
  • EP3910914B1 patent drawingFigure 2

AI summary

The present invention relates to a contention mitigation method (200) for an operational application implemented by an embedded platform comprising a plurality of cores and a plurality of shared resources. This method consists of the steps of executing (210) the operational application by one of the cores of the embedded platform, executing (220) a stressful application on at least some other cores of the embedded platform in parallel with the operational application, the stressful application being composed of a set of contention tasks generating maximum contention on interference channels, and determining (230) the contentions generated by the stressful application on the operational application.