earticle

영어

In hierarchical scheduling, a system is organised as a tree of nodes, where each node schedules its child nodes. A node contains tasks and/or subsystems, where a subsystem is typically produced by a development team. Given a system where each part is subcontracted to different developers, they can benefit from hierarchical scheduling by parallel development and simplified integration of subsystems. Each team should have the possibility to test their system before integration. Hence, we show how a node in a hierarchical scheduling tree can be analysed by the Times tool by replacing all interference from nodes with a small set of higher priority tasks. We show an algorithm that can generate these tasks, including their parameters. Furthermore, we use the Times code-generator, in combination with operating system extensions, to generate source code that emulates the scheduling environment for a subsystem at an arbitrary level in the tree. Our experiments include two example systems. In the first case we generate source code for an industrial oriented platform (VxWorks) and conduct a performance evaluation. In the second example we generate source code that emulates the scheduling environment for a video application, running in Linux, and we perform a frame-rate evaluation.