A synchronous scheduling service for distributed real-time Java
Download as PPT, PDF0 likes567 views
1) The document presents a Synchronous Scheduling Service (SSS) that introduces time-triggered orientation for distributed real-time Java applications. 2) The SSS is based on the Flexible Time-Triggered protocol and is supported as a new service in the Distributed Real-Time Specification for Java. 3) It provides a more predictable network management which is useful for high-integrity applications.
![Master-slave
Jitter [new] templates
Convergence
time vs. event triggered
Layer
DREQUIEMI
J2ME-RMIOP
JTime
TimesysOs
JRT-11 18](https://image.slidesharecdn.com/2011-jtr-pbasanta-sss-130123023152-phpapp01/85/A-synchronous-scheduling-service-for-distributed-real-time-Java-18-320.jpg)
A synchronous scheduling service for distributed real-time Java
- 1. A synchronous scheduling service (SSS) for distributed real-time Java Pablo Basanta-Val, Iria Estévez-Ayres, Marisol García-Valls, and Luis Almeida mailto:pbasanta@it.uc3m.es †Jornadas de Tiempo Real 2011- Madrid( ) Publicado en IEEE Transactions on Parallel and Distributed Systems
- 2. Outline • Context and Motivation • FTT and DREQUIEMI integration • SSS (Synchronous Scheduling Service) – Master Slave Model – Choreographies – Choreographies scheduling/scheduler – Architecture and examples – Performance • Conclusion and ongoing work 2
- 3. Context • Java programmers may use two specifications for develop their real-time applications – RTSJ: The Real-Time Specification for Java – DRTSJ: The Distributed Real-Time Specification for Java • DRTSJ has focused on remote object upcalling and abstractions (distributable threads). – But not in a predictable networks – Networks predictability is a requirement JRT-11 3
- 4. In this work • We introduce time-triggered orientation in distributed real-time Java – Basic model used the FTT (Flexible Time-Triggered) protocol – Supported as a new service in distributed real-time Java • SSS (Synchronous Scheduling Service) • We obtain a more predictable network management – Useful for instance in high-integrity applications JRT-11 4
- 5. FTT and DREQUIEMI integration (1/3) JRT-11 5
- 6. FTT and DREQUIEMI integration (2/3) JRT-11 6
- 7. FTT and DREQUIEMI integration (3/3) JRT-11 7
- 8. System overview JRT-11 8
- 9. Choreographies set JRT-11 9
- 10. T and S choreographies JRT-11 10
- 11. C and P choreographies JRT-11 11
- 12. Scheduling Choreographies • Each choreography is modeled as non preemptive task – {O, T, C, D} • The choreographies executed by the master - It runs a NPR-EDF - Simple admission control (T=D) JRT-11 12
- 13. Implementation issues: Convergence Layer JRT-11 13
- 14. Example 1: real-time producer consumer (1/2) Every 10 ms Maximum Process data generates a network delay: coming from a sample 20 ms producer 10 10 producer consumer slave slave JRT-11 14
- 15. Example real-time producer consumer (2/2) Every 10 ms Maximum network Process data generates a sample delay: coming from a 20 ms producer 10 10 producer consumer slave slave PC# Produce# producer # CC.data O= 5ms master T= 10 ms C= 2 ms D= 10 ms NPR-EDF CC # Consume# consumer# O= 15 ms T= 10 ms C= 2 ms D= 10 ms JRT-11 15
- 16. Experiments (1/2) Master-slave templates End-to-End costs (us) Convergence Layer over 796 MHz-100Mbps DREQUIEMI J2ME-RMIOP JTime TimesysOs JRT-11 16
- 17. Experiments (2/2) Master-slave templates End-to-End costs (bytes) Convergence Layer over 796 MHz-100Mbps DREQUIEMI J2ME-RMIOP JTime TimesysOs
- 18. Master-slave Jitter [new] templates Convergence time vs. event triggered Layer DREQUIEMI J2ME-RMIOP JTime TimesysOs JRT-11 18
- 19. Conclusions • Developed techniques to include time-triggered orientation in distributed real-time Java – Synchronous Scheduling Service (SSS) • Empirical evidences showed better performance than an ET approach – Because TCP/IP stacks and OS are not fully preemptive JRT-11 19
- 20. Ongoing work • Developing a minimum time-triggered implementation without DREQUIEMI – Ongoing master thesis • Changes in the model – NPR-RMS model vs. NPR-EDF – One way choreographies JRT-11 20
- 21. JRT-11 21