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Several approaches to extend the original Android implementation with real-time capabilities were presented in the last few years. Most of the research was limited to fundamental issues like real-time scheduling and non-blocking memory management. This paper demonstrates the weak predictability of Android's intra-and inter-process communication and presents a concept to improve its soft real-time capability. The proposed approach introduces a priority-based broadcast handling, instead of the original first in -first out processing. Additionally, we reduce the size of responsible critical sections in order to improve the preemptibility and assure predictable delays for applications with real-time requirements. Our empirical evaluation highlights the improvements in comparison to the original Android implementation without loss of the performance for both global and local broadcast systems. Furthermore, the compatibility to already existing components and applications is preserved.

No abstract

Different approaches for extending the original Android platform with real-time capabilities were presented in the last few years. Most of the work covers fundamental issues like real-time scheduling and non-blocking memory management. This article shows the weak predictability of Android's internal intra-process and inter-process communication based on Intent messaging and presents a concept to improve its soft real-time capability. The proposed approach introduces a priority-based broadcast handling using explicit priority values, instead of the original first in -first out processing. Furthermore, the size of responsible critical sections is reduced in order to improve the preemptibility and to assure predictable processing times for applications with real-time requirements. Our evaluation highlights the improvements in comparison with the original Android implementation without any loss of the system performance. Additionally, the compatibility with already existing components and applications is preserved. collection to achieve a predictable process behavior and significantly reduce maximal scheduling latencies for real-time applications.In addition to process and memory management, a real-time capable operating system should provide safe and predictable methods for intra-process and inter-process communication (IPC). Android implements its own IPC concept -a rich system-wide messaging mechanism based on Intents and Broadcast Receivers [8,9]. Whereas a lot of security-related research is currently carried out on this topic, only little effort is invested in the evaluation of its reliability and suitability in the context of real-time systems.This paper presents an approach to enhance RTAndroid's soft real-time properties by improving the predictability of the transmitted Intent messages. As the original broadcast management in Android is mainly built on unordered data structures and blocking operations, our implementation introduces a priority-based approach with bounded handling delays, which is crucial for platforms with real-time support. Furthermore, the modified RTAndroid platform remains fully backward compatible to already existing Android components and third-party applications. Specifically, the key contributions of this work are Investigation of broadcast-related components and their suitability for real-time applications Concept design and extension of the original implementation for predictable message handling Performance evaluation of the new architecture and analysis of the introduced system changes This article is an extended version of work [10] that was previously published in the Proceedings of ACM JTRES 2014. It describes the updated prioritization mechanism with additional application examples and related evaluation of performance and correctness. The approach is intentionally chosen to extend the orignal framework, instead of create a new real-time messaging system from scratch and integrate it into the platform. This is carried out in order to minimize the required system changes and t...