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LetSynchronise

LetSynchronise is extensible, web-based, open-source (GPL3) framework for modelling, simulating, analysing, and optimising LET-based systems. It currently focuses on timing behaviour and does not support the modelling of, e.g., functional behaviour, data values, or memory usage. The target audience of LetSynchronise is researchers who wish to (1) rapidly prototype and experiment with LET schedul- ing policies and optimisations, (2) make solutions and benchmarks readily accessible, and (3) fairly and accurately reproduce and eval- uate the results of existing work.

Dependencies

• Web browser that supports indexedDB: System database
• D3 Data-Driven Documents: Charting
• Bootstrap: User interface and layout

Directory Layout

• dependencies: JavaScript frameworks and libraries
• docs: Documentation on architecture and plugin feature
• playground: Examples to learn JavaScript and frameworks
• sources: Organised into the model-view-controller architecture
  • controller: Links the view and model together
  • model: System model
  • view: User interface
  • plugins: Extensions for importing, exporting, analysing, scheduling, and optimising systems

Usage

LetSynchronise is designed as a web application that does not require any installation. Just open the sources/ls.main.html file in a web browser, e.g., Firefox or Safari. There are two tabs for users to Design and then to Analyse a LET system. See the docs folder for information on the types of plugins that are available and can be developed.

Systems can be imported and exported via supported file formats. If only certain system elements should be imported or exported, these can be selected beforehand via tick boxes.

Note LetSynchronise uses a time base of nanoseconds to avoid rounding errors.

Design Tab

• Edit the system interface in terms of the environmental inputs and outputs.
• Edit the system's LET task set, and view each task's parameters diagramatically.
• Edit task communication dependencies among the system interface and tasks.

Analyse Tab

• View the prologue and hyper-period of the task set.
• Define the makespan of the task schedule to simulate.
• Choose a task scheduler that implements the desired scheduling policy.
• Choose the type (BCET, ACET, or WCET) of execution times to simulate for each task instance.
• Choose an optimisation goal to apply on the system.
• View the simulated task schedule, including the overall system load.
• Show or hide each task communication dependency.
• Interactive tooltips appear the mouse is hovered over each LET interval, execution interval, and task communication dependency.
• Edit event chains, which represent sequences of task communication dependencies.
• Highlight each instance of a selected event chain.
• Define timing constraints on event chains, which will be analysed and used during optimisation.
• View analysis results for timing constraints.

Development

LetSynchronise is based on the model-view-controller architecure and details can be found in the docs folder. The main logic and plugins are programmed in JavaScript. The system model and simulated schedule are stored in IndexeDB. The user interface is styled with Bootstrap. The simulated schedules are plotted with D3.

Code Style

• Indentation: 4 spaces
• Names: camel casing