Static Partition Scheduling Timeline for Avionics Context Switch Reduction

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Solution Overview

Problem

The ARINC-653 specification for avionics systems requires a static allocation of memory space and execution time for partitions, but lacks guidance on generating a scheduling timeline that minimizes context switches between partitions.

Innovation Solution

A method and system that model each partition as a period and duration, allocating execution time in a repeating sequence of activation frames using the earliest deadline first prioritization technique, and merging adjacent slices to minimize context switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a static allocation of memory space and execution time is implemented for each partition as required by ARINC-653, then safety and isolation requirements are met, but the number of context switches between partitions increases

Engineering Contradiction:

Improvesafety isolationVSAvoidcontext switching overhead

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent merges adjacent slices of the same partition into continuous time blocks within the scheduling timeline. By combining multiple discrete time allocations for the same partition into contiguous segments, the number of context switches between partitions is reduced while maintaining the required static time allocation and safety isolation guarantees of ARINC-653.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple partitions with various frame times are supported, then system versatility is improved, but the complexity of generating the scheduling timeline increases

Engineering Contradiction:

Improvemulti-partition supportVSAvoidscheduling timeline generation

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the scheduling timeline into discrete slices organized by partition and frame. By dividing the complex scheduling problem into manageable segments (slices) that can be independently allocated and then merged, the system can support multiple partitions with various frame times while reducing the overall complexity of timeline generation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary allocation of time slices to partitions based on their frame times and execution requirements before generating the final merged timeline. This preliminary organization of slices by partition and temporal position simplifies the subsequent merging process and makes the overall scheduling timeline generation more manageable.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7788673B2Method and system for generating a static partition scheduling timeline with reduced context switching overhead

Publication Date: 2010.08.31 HONEYWELL INTERNATIONAL INC

AI summary

A static partition scheduling timeline is generated by identifying a plurality of partitions for scheduling, the partitions associated with a operating system that executes on a processing unit. A first plurality of Activation Frames for a first partition of said plurality of partitions is defined, a second plurality of Activation Frames for a second partition of said plurality of partitions is defined, a first plurality of slices within at least one Activation Frame of said first plurality of Activation Frames is defined, and a second plurality of slices within at least one Activation Frame of said second plurality of Activation Frames is defined. The static partition scheduling timeline comprises the first plurality of Activation Frames, the second plurality of Activation Frames, the first plurality of slices, and the second plurality of slices. The operating system is configured to use the generated static partition scheduling timeline.