Modular and dynamic Realtime Java applications based on OSGi and RTSJ are not a novelty anymore. The combination of both technologies provides a powerful framework for dynamic and "open" real-time systems and platforms. In such systems real-time applications can be dynamically composed or updated based on newly deployed components and services. While OSGi seems to be an intuitive solution for online updatability, composition and reconfigurability of applications and components, Realtime Java offers a standardized programmability layer for applications with strict execution and performance requirements. However, are these technologies and their combination sufficient enough to cover all necessary aspects of respective platforms and infrastructures?
Requirements on opennes combined with performance guarantees are not only increasingly seen for embedded systems in general, like in the automotive or industrial fields. They are emergent for contemporary and future edge and fog computing systems, use cases and infrastructures. On the one side, these systems allow for flexible and dynamic application arrival and departure, reconfigurability and appropriate life-cycle management. On the other side, often they have to guarantee and meet certain performance and QoS criteria for applications, e.g. a computational throughput, timeliness aspects, isolation, etc. As a result, dynamic computational loads have to be handled and managed, bottlenecks must be omitted or smoothed during run time and therefore platform resources must be organized and scheduled correctly in order to meet systems quality criteria.
However, for such open platforms many questions and respective mechanisms still remain open. For example, which utilization bounds exist, who performs admission control and feasibility tests, how can isolation between applications and their components be realized, or how can load be degraded in case of permanent bottlenecks.
This talk will focus on these questions, it will emphasize on the theoretical state of the art and also discuss some practical solutions which already exist.