Suporte à Degradação Controlada em Sistemas de Tempo Real
Resumo
Nos sistemas de tempo real, rotinas de recuperação de falhas podem ser modeladas como tarefas aperiódicas que devem cumprir seus prazos de execução sem inviabilizar a correção temporal do sistema como um todo. Para tanto, é necessário o desenvolvimento de mecanismos adequados e eficientes de escalonamento. Este artigo descreve um modelo de escalonamento para tolerância a falhas no qual as rotinas de recuperação são admitidas mediante à degradação controlada da qualidade do serviço de tarefas periódicas. O modelo foi avaliado por simulação e os resultados encontrados indicam a eficácia da abordagem proposta.
Referências
Aydin, H. (2004). “On Fault-Sensitive Feasibility Analysis of Real-Time Task Sets”. In Proc. of the 25th IEEE International Real-Time Systems Symposium (RTSS’04), pages 426–434. IEEE Computer Society.
Burns, A., Davis, R. I., and Punnekkat, S. (1996). “Feasibility Analysis of Fault-Tolerant Real-Time Task Sets”. In Proc. of the Euromicro Real-Time Systems Workshop, pages 29–33. IEEE Computer Society Press.
Burns, A. and Wellings, A. J. (2001). “Real-Time Systems and Programming Languages”. Addison-Wesley, 3rd edition.
Buttazzo, G. C. and Stankovic, J. (1993). “Red: A Robust Earliest Deadline Scheduling Algorithm”. In Proc. of 3rd International Workshop on Responsive Computing Systems.
Caccamo, M. and Buttazzo, G. (1998). “Optimal Scheduling for Fault-Tolerant and Firm Real-Time Systems”. In Proc. of the 5th Conference on Real-Time Computing and Applications (RTCSA), pages 223–231.
de Jesus, E. O. and Lima, G. (2005). “Escalonamento para Sistemas de Tempo-Real Tolerantes a Falhas: Um Estudo Empírico”. In Proc. of the Brazilian Real-Time Workshop (WTR 05), pages 69–72. Brazilian Computer Society.
de Oliveira, R. S. (1997). “Computação Imprecisa”. Revista de Informática Teórica e Aplicada - RITA, 4(1).
Ghosh, S., Melhem, R. G., and Mossé, D. (1995). “Enhancing Real-Time Schedules to Tolerate Transient Faults”. In Proc. of the 16th Real-Time Systems Symposium (RTSS), pages 120–129. IEEE Computer Society Press.
Ghosh, S., Melhem, R. G., Mossé, D., and Sarma, J. S. (1998). “Fault-Tolerant Rate-Monotonic Scheduling”. Real-Time Systems, 15(2):149–181.
González, O., Shrikumar, H., Stankovic, J. A., and Ramamritham, K. (1997). “Adaptive Fault Tolerance and Graceful Degradation under Dynamic Hard Real-Time Scheduling”. In Proc. of the 18th Real-Time Systems Symposium (RTSS). IEEE Computer Society Press.
Kandasamy, N., Hayes, J. P., and Murray, B. T. (1999). “Tolerating Transient Faults in Statically Scheduled Safety-Critical Embedded Systems”. In Proc. of the 18th IEEE Symposium on Reliable Distributed Systems (SRDS), pages 212–221.
Kopetz, H. (1997). “Real-Time System s Design for Distributed Embedded Applications”. Kluwer Academic Publishers.
Liberato, F., Melhem, R. G., and Mossé, D. (2000). “Tolerance to Multiple Transient Faults for Aperiodic Tasks in Hard Real-Time Systems”. IEEE Transactions on Com puters, 49(9):906–914.
Liestman, L. and Campbell, R. H. (1986). “A Fault-Tolerant Scheduling Problem”. IEEE Transaction on Software Engineering, 12(11):1089–1095.
Lima, G. and Burns, A. (2005). “Scheduling Fixed-Priority Hard Real-Time Tasks in the Presence of Faults”. In Dependable Computing: Second Latin-American Symposium, LADC, volume LNCS 3747, pages 154–173. Springer-Verlag.
Lima, G. M. A. and Burns, A. (2003). “An Optimal Fixed-Priority Assignment Algorithm for Supporting Fault Tolerant Hard Real-Time Systems”. IEEE Transaction on Computers, 52(10):1332–1346.
Liu, C. L. and Layland, J. W. (1973). “Scheduling Algorithms for Multiprogram in a Hard Real-Time Environment”. Journal of ACM, 20(1):40–61.
Liu, J. W. S. (2000). “Real-Time Systems”. Prentice-Hall.
Marucheck, M. and Strosnider, J. (1995). “An Evaluation of the Graceful Degradation Properties of real-time Schedulers”. In Proc. of the 25th Annual International Symposium on Fault-Tolerant Computing.
Poledna, S. (1996). “Fault-Tolerant Real-Time Systems: The Problem of Replica Determinism”. Kluwer Academic Publishers.
Ramos-Thuel, S. and Strosnider, J. K. (1991). “The Transient Server Approach to Scheduling Time-Critical Recovery Operations”. In Proc. of the 12th Real-Time Systems Symposium (RTSS), pages 286–295. IEEE Computer Society Press.
Spuri, M. and Buttazzo, G. (1996). “Scheduling Aperiodic Tasks in Dynamic Priority Systems”. Real Time Systems, 10(2):179–210.
Burns, A., Davis, R. I., and Punnekkat, S. (1996). “Feasibility Analysis of Fault-Tolerant Real-Time Task Sets”. In Proc. of the Euromicro Real-Time Systems Workshop, pages 29–33. IEEE Computer Society Press.
Burns, A. and Wellings, A. J. (2001). “Real-Time Systems and Programming Languages”. Addison-Wesley, 3rd edition.
Buttazzo, G. C. and Stankovic, J. (1993). “Red: A Robust Earliest Deadline Scheduling Algorithm”. In Proc. of 3rd International Workshop on Responsive Computing Systems.
Caccamo, M. and Buttazzo, G. (1998). “Optimal Scheduling for Fault-Tolerant and Firm Real-Time Systems”. In Proc. of the 5th Conference on Real-Time Computing and Applications (RTCSA), pages 223–231.
de Jesus, E. O. and Lima, G. (2005). “Escalonamento para Sistemas de Tempo-Real Tolerantes a Falhas: Um Estudo Empírico”. In Proc. of the Brazilian Real-Time Workshop (WTR 05), pages 69–72. Brazilian Computer Society.
de Oliveira, R. S. (1997). “Computação Imprecisa”. Revista de Informática Teórica e Aplicada - RITA, 4(1).
Ghosh, S., Melhem, R. G., and Mossé, D. (1995). “Enhancing Real-Time Schedules to Tolerate Transient Faults”. In Proc. of the 16th Real-Time Systems Symposium (RTSS), pages 120–129. IEEE Computer Society Press.
Ghosh, S., Melhem, R. G., Mossé, D., and Sarma, J. S. (1998). “Fault-Tolerant Rate-Monotonic Scheduling”. Real-Time Systems, 15(2):149–181.
González, O., Shrikumar, H., Stankovic, J. A., and Ramamritham, K. (1997). “Adaptive Fault Tolerance and Graceful Degradation under Dynamic Hard Real-Time Scheduling”. In Proc. of the 18th Real-Time Systems Symposium (RTSS). IEEE Computer Society Press.
Kandasamy, N., Hayes, J. P., and Murray, B. T. (1999). “Tolerating Transient Faults in Statically Scheduled Safety-Critical Embedded Systems”. In Proc. of the 18th IEEE Symposium on Reliable Distributed Systems (SRDS), pages 212–221.
Kopetz, H. (1997). “Real-Time System s Design for Distributed Embedded Applications”. Kluwer Academic Publishers.
Liberato, F., Melhem, R. G., and Mossé, D. (2000). “Tolerance to Multiple Transient Faults for Aperiodic Tasks in Hard Real-Time Systems”. IEEE Transactions on Com puters, 49(9):906–914.
Liestman, L. and Campbell, R. H. (1986). “A Fault-Tolerant Scheduling Problem”. IEEE Transaction on Software Engineering, 12(11):1089–1095.
Lima, G. and Burns, A. (2005). “Scheduling Fixed-Priority Hard Real-Time Tasks in the Presence of Faults”. In Dependable Computing: Second Latin-American Symposium, LADC, volume LNCS 3747, pages 154–173. Springer-Verlag.
Lima, G. M. A. and Burns, A. (2003). “An Optimal Fixed-Priority Assignment Algorithm for Supporting Fault Tolerant Hard Real-Time Systems”. IEEE Transaction on Computers, 52(10):1332–1346.
Liu, C. L. and Layland, J. W. (1973). “Scheduling Algorithms for Multiprogram in a Hard Real-Time Environment”. Journal of ACM, 20(1):40–61.
Liu, J. W. S. (2000). “Real-Time Systems”. Prentice-Hall.
Marucheck, M. and Strosnider, J. (1995). “An Evaluation of the Graceful Degradation Properties of real-time Schedulers”. In Proc. of the 25th Annual International Symposium on Fault-Tolerant Computing.
Poledna, S. (1996). “Fault-Tolerant Real-Time Systems: The Problem of Replica Determinism”. Kluwer Academic Publishers.
Ramos-Thuel, S. and Strosnider, J. K. (1991). “The Transient Server Approach to Scheduling Time-Critical Recovery Operations”. In Proc. of the 12th Real-Time Systems Symposium (RTSS), pages 286–295. IEEE Computer Society Press.
Spuri, M. and Buttazzo, G. (1996). “Scheduling Aperiodic Tasks in Dynamic Priority Systems”. Real Time Systems, 10(2):179–210.
Publicado
29/05/2007
Como Citar
SOKOLONSKI, Ana Carolina; LIMA, George; BARRETO, Luciano Porto.
Suporte à Degradação Controlada em Sistemas de Tempo Real. In: WORKSHOP DE TESTES E TOLERÂNCIA A FALHAS (WTF), 8. , 2007, Belém/PA.
Anais [...].
Porto Alegre: Sociedade Brasileira de Computação,
2007
.
p. 29-42.
ISSN 2595-2684.
DOI: https://doi.org/10.5753/wtf.2007.23237.
