OPAM: Optimal Priority Assignment Method for real-time tasks

In real-time systems, priorities assigned to real-time tasks determine the order of task executions, by relying on an underlying task scheduling policy. Assigning optimal priority values to tasks is critical to allow the tasks to complete their executions while maximizing safety margins from their specified deadlines. This enables real-time systems to tolerate unexpected overheads in task executions and still meet their deadlines. In practice, priority assignments result from an interactive process between the development and testing teams. In this article, we propose an automated method that aims to identify the best possible priority assignments in real-time systems, accounting for multiple objectives regarding safety margins and engineering constraints. Our approach is based on a multi-objective, competitive coevolutionary algorithm mimicking the interactive priority assignment process between the development and testing teams. We evaluate our approach by applying it to six industrial systems from different domains and several synthetic systems. The results indicate that our approach significantly outperforms both random search and solutions defined by practitioners. Our approach scales to complex industrial systems as an offline analysis method that attempts to find (near-)optimal solutions within acceptable time, i.e., less than two days.

OPAM runs on the following operating systems:

• Centos Linux 7 (Core, Linux 3.10.0-957.1.3.el7.x86_64)
• MacOS 10.15.7

• Java 1.8.0.162 (Dependencies: see the file PriorityAssignment/pom.xml)
• Python 3.7+ (Dependencies: see the file scripts/Python/requirements.txt)
• R 4.1.0+ (Dependencies: see the file scripts/R/requirements.R)

• PriorityAssignment : Containing Java source code of OPAM
• UPPAAL : Containing the result of our preliminary experiment using UPPAAL (uppaal64-4.1.24)
• res: Containing input files - task descriptions
• scripts: Containing script files to collect data and to generate graphs
• results: Containing results files during all experiments
• settings.json: Parameters for the Java executable files
• *.sh: Shell scripts for conducting experiments

Given the pre-configured POM files for Maven in the PriorityAssignment folder, you can create executable jar files that are used in the shell script files contained in this repository. Please execute the below commands in the PriorityAssignment folder.

• OPAM.jar: mvn -f opam.pom -DoutputJar=../artifacts package
• OPAM-Ext.jar: mvn -f opam.ext.pom -DoutputJar=../artifacts package
• QI.jar: mvn -f qi.pom -DoutputJar=../artifacts package
• QI-Ext.jar: mvn -f qi.ext.pom -DoutputJar=../artifacts package
• NSGA.jar: mvn -f nsga.pom -DoutputJar=../artifacts package
• Synthesizer.jar: mvn -f synthesizer.pom -DoutputJar=../artifacts package

• Step 1: Run run.sh
• Step 2: See output files in results/OPAM

• Step 1: Run exp1.sh for each subject
• Step 2: See output files in results/RQ1/OPAM and results/RQ1/RS

• Step 1: Run exp2.sh for each subject
• Step 2: See output files in results/RQ2/OPAM and results/RQ2/SEQ

• Step 1: Run exp3.gen.sh
• Step 2: Run exp3.1.sh ~ exp3.4.sh
• Step 3: See output files in results/RQ3

• Step 1: Running exp4.sh
• Step 2: See output files in results/RQ4