An Interface Algebra for Real-Time Components

We present an assume-guarantee interface algebra for real-time components. In our formalism a component implements a set of task sequences that share a resource. A component interface consists of an arrival rate function and a latency for each task sequence, and a capacity function for the shared resource. The interface specifies that the component guarantees certain task latencies depending on assumptions about task arrival rates and allocated resource capacities. Our algebra defines compatibility and refinement relations on interfaces. Interface compatibility can be checked on partial designs, even when some component interfaces are yet unknown. In this case interface composition computes as new assumptions the weakest constraints on the unknown components that are necessary to satisfy the specified guarantees. Interface refinement is defined in a way that ensures that compatible interfaces can be refined and implemented independently. Our algebra thus formalizes an interface-based design methodology that supports both the incremental addition of new components and the independent stepwise refinement of existing components. We demonstrate the flexibility and efficiency of the framework through simulation experiments.

[1]  Thomas A. Henzinger,et al.  Interface automata , 2001, ESEC/FSE-9.

[2]  Thomas A. Henzinger,et al.  Timed Interfaces , 2002, EMSOFT.

[3]  Aloysius K. Mok,et al.  Towards compositionality in real-time resource partitioning based on regularity bounds , 2001, Proceedings 22nd IEEE Real-Time Systems Symposium (RTSS 2001) (Cat. No.01PR1420).

[4]  Riccardo Bettati,et al.  Real-time component-based systems , 2005, 11th IEEE Real Time and Embedded Technology and Applications Symposium.

[5]  Aloysius K. Mok,et al.  A model of hierarchical real-time virtual resources , 2002, 23rd IEEE Real-Time Systems Symposium, 2002. RTSS 2002..

[6]  Luís Almeida,et al.  Scheduling within temporal partitions: response-time analysis and server design , 2004, EMSOFT '04.

[7]  Thomas A. Henzinger,et al.  Interface Theories for Component-Based Design , 2001, EMSOFT.

[8]  Giuseppe Lipari,et al.  Resource partitioning among real-time applications , 2003, 15th Euromicro Conference on Real-Time Systems, 2003. Proceedings..

[9]  Lothar Thiele,et al.  Real-time interfaces for interface-based design of real-time systems with fixed priority scheduling , 2005, EMSOFT.

[10]  John P. Lehoczky,et al.  Timing Analysis for Fixed-Priority Scheduling of Hard Real-Time Systems , 1994, IEEE Trans. Software Eng..

[11]  Jane W.-S. Liu,et al.  Scheduling real-time applications in an open environment , 1997, Proceedings Real-Time Systems Symposium.

[12]  Insup Lee,et al.  Compositional real-time scheduling framework , 2004, 25th IEEE International Real-Time Systems Symposium.

[13]  John Regehr,et al.  HLS: a framework for composing soft real-time schedulers , 2001, Proceedings 22nd IEEE Real-Time Systems Symposium (RTSS 2001) (Cat. No.01PR1420).

[14]  S. Goddard,et al.  Proceedings of the twelfth IEEE Real-Time and Embedded Technology and Applications Symposium, 4-7, April 2006, San Jose, California , 2006 .

[15]  Aloysius K. Mok,et al.  Resource partition for real-time systems , 2001, Proceedings Seventh IEEE Real-Time Technology and Applications Symposium.

[16]  Insup Lee,et al.  Periodic resource model for compositional real-time guarantees , 2003, RTSS 2003. 24th IEEE Real-Time Systems Symposium, 2003.