System Schedule

A System Schedule collects the schedules for all involved resources in the associated Allocation that defines the mapping of the elements of a Task Architecture to the underlying hardware Platform Architecture). An important attribute of a system schedule is its Major Frame (MAF) that is defined as the period of time to be considered when computing the task allocation and scheduling. The MAF of a System Schedule is normally equal to the least-common multiple (LCM) of the periods of all ResourceSchedules, but can be less than this value under certain conditions such as harmonicity or geometricity of periods.

The schedule of each individual resource is described using a Resource Schedule. The allocation of a share of the resource referenced by a Resource Schedule is expressed using a Resource Allocation.

The AutoFOCUS3 schedule model enables to describe hierarchical schedules. The share of a resource described by a Resource Allocation allocated in a Resource Schedule can be further sub-divided by declaring a Sub Schedule for it. Sub Schedules apply the concept recursively, i.e., they also contain Resource Allocations that reference a SchedulableEntity and a Trigger. A Sub-Schedule does however not reference a platform resource, since it refines another Resource Allocation. Triggers specify the temporal activation pattern of Resource Allocations.

The figure below shows the Gantt chart of an exemplary schedule.

Due to the inherent complexity of the problem, (real-time) schedules are typically not defined manually, but are synthesized automatically. To enable comfortable testing, the modeling perspective of AutoFOCUS3 provides a minimal schedule editor that is based on the model navigator and the properties section. This means that system schedules can be created using the context menu of the project, resource schedules can be added in the context menu of a system schedule, etc.

To view a Gantt chart of a system schedule in the modeling perspective, the Schedule View needs to be activated from the dialog that is shown by hitting ALT+SHIFT+Q followed by Q. The view will render the system schedule that has been selected last in the model navigator.