한국정보과학회논문지:시스템및이론 (Journal of KIISE:Computer Systems and Theory)

한국정보과학회 (Korean Institute of Information Scientists and Engineers)
권호 표지

서비스율을 보장하는 지연시간-대역폭 정규화 스케줄링 모델

A Delay-Bandwidth Normalized Scheduling Model with Service Rate Guarantees

  • 이주현 (서울대학교 전기컴퓨터공학부) ;
  • 황호영 (한성대학교 멀티미디어공학과) ;
  • 이창건 (서울대학교 컴퓨터공학부) ;
  • 민상렬 (서울대학교 컴퓨터공학부)
  • 발행 : 2007.10.15
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

Generalized Processor Sharing(GPS) 기반의 공정큐잉(Fair Queueing) 알고리즘들은 세션들에게 서비스율과 지연시간 보장 서비스를 제공할 뿐만 아니라, 순시적 공유(instantaneous sharing)를 통해 각 세션에게 공정서비스를 제공한다. 이 공정서비스는 현재 서버에 대기중인 세션들의 과거에 받은 서비스 양에 관계없이 그 세션의 가중치에 비례하여 서버 용량을 분배한다. 그러나 이 공정서비스는 장기적 측면에서 같은 가중치를 가지는 세션에게 세션의 트래픽 패턴에 따라 다른 지연시간과 대역폭 QoS(Quality of Service)를 제공한다. 이러한 장기적 측면의 불공정 서비스를 최소화하기 위해, 본 논문에서는 지연시간과 대역폭 관점에서 서비스 가치(Value of Service)를 정의한 지연시간-대역폭 정규화 모델을 제안한다. 이 정규화 모델에서 정의한 서비스 가치 개념을 사용하여 각 세션에게 지연시간-대역폭 관점의 공정한 서비스를 제공하는 스케줄링 알고리즘을 제안한다. 제안된 알고리즘과 기존의 공정큐잉 및 서비스 커브 기반의 알고리즘과 비교를 통해 제안된 알고리즘은 세션들에게 장기적 측면의 공정서비스를 제공하고, 다양한 트래픽 특성을 갖는 세션에 대해 서비스율과 지연시간 보장에 대한 재조정 없이 동적으로 트래픽 특성에 적응하여 서비스하는 것을 관찰할 수 있다.

Fair Queueing algorithms based on Generalized Processor Sharing (GPS) not only guarantee sessions with service rate and delay, but also provide sessions with instantaneous fair sharing. This fair sharing distributes server capacity to currently backlogged sessions in proportion to their weights without regard to the amount of service that the sessions received in the past. From a long-term perspective, the instantaneous fair sharing leads to a different quality of service in terms of delay and bandwidth to sessions with the same weight depending on their traffic pattern. To minimize such long-term unfairness, we propose a delay-bandwidth normalization model that defines the concept of value of service (VoS) from the aspect of both delay and bandwidth. A model and a packet-by-packet scheduling algorithm are proposed to realize the VoS concept. Performance comparisons between the proposed algorithm and algorithms based on fair queueing and service curve show that the proposed algorithm provides better long-term fairness among sessions and that is more adaptive to dynamic traffic characteristics without compromising its service rate and delay guarantees.

키워드

참고문헌

  1. A. Parekh and R. Gallager, 'A Generalized Processor Sharing Approach to Flow Control in Integrated Services Networks: The Single-Node Case,' IEEE/ACM Trans. on Networking, vol. 1, no. 3, pp. 344-357, 1993 https://doi.org/10.1109/90.234856
  2. A. Demers, S. Keshav, and S. Shenker, 'Analysis and Simulation of a Fair Queueing Algorithm,' in Proc. of ACM SIGCOMM, pp. 1-12, 1989
  3. J. Bennett and H. Zhang, 'WF2Q: Worst-case Fair Weighted Fair Queueing,' in Proc. of IEEE INFOCOM, pp. 120-128, 1996
  4. L. Zhang, 'VirtualClock: A New Traffic Control Algorithm for Packet-Switched Networks,' ACM Trans. on Computer Systems, vol. 9, no. 2, pp. 101-124,May 1991 https://doi.org/10.1145/103720.103721
  5. P. Goyal, H. Vin, and H. Cheng, 'Start-Time Fair Queueing: A Scheduling Algorithm for Integrated Services Packet Switching Networks,' IEEE/ACM Trans. on Networking, vol. 5, no. 5, pp. 690-704, 1997 https://doi.org/10.1109/90.649569
  6. S. Golestani, 'A Self-clocked Fair Queueing Scheme for Broadband Applications,' in Proc. of IEEE INFOCOM, pp. 636-646, 1994
  7. J. Bennett and H. Zhang, 'Hierarchical Packet Fair Queueing Algorithms,' IEEE/ACM Trans. on Networking, vol. 5, no. 2, pp. 675-689, Oct. 1997 https://doi.org/10.1109/90.649568
  8. S. Suri, G. Varghese and G. Ghandramnenon, 'Leap Forward Virtual Clock: A New Fair Queueing Scheme with Guaranteed Delays and Throughput Fairness,' in Proc. of IEEE INFOCOM, pp. 557-565, 1997
  9. S. Lu, V. Bharghavan, and R. Srikant, 'Fair Scheduling in Wireless Packet Networks,' IEEE/ACM Trans. on Networking, vol. 7, no. 4, pp. 473-489, 1999 https://doi.org/10.1109/90.793003
  10. T. S. E. Ng, D. C. Stephens, I. Stoica, and H. Zhang, 'Supporting Best-Effort Traffic with Fair Service Curve,' in Proc. of IEEE GLOBECOM, pp. 1799-1807, 1999
  11. R. Cruz, 'Quality of Service Guarantees in Virtual Circuit Switched Networks,' IEEE Journal on Selected Areas in Communications, vol. 13, no. 6, pp. 1048-1056, 1995 https://doi.org/10.1109/49.400660
  12. H. Sariowan, 'SCED: A Generalized Scheduling Policy for Guaranteeing Quality-of-Service,' IEEE/ACM Trans. on Networking, vol. 7, no. 5, pp. 669-684, 1999 https://doi.org/10.1109/90.803382
  13. I. Stoica, H. Zhang, and T. S. E. Ng, 'A Hierarchical Fair Service Curve Algorithm for Link-Sharing, Real-Time, and Priority Services,' IEEE/ACM Trans. on Networking, vol. 8, no. 5, pp. 185-199, April. 2000 https://doi.org/10.1109/90.842141
  14. S. Wang, Y. C. Wang, and K. J. Lin, 'A Priority- Based Weighted Fair Queueing Scheduler for Real-Time Network,' in Proc. of IEEE RTCSA, pp. 312-319, 1999
  15. D. Stiliadis and A. Verma, 'Efficient Fair Queueing Algorithms for Packet-Switched Networks,' IEEE/ACM Trans. on Networking, vol. 6, no. 2, pp. 175-185, April 1998 https://doi.org/10.1109/90.664266
  16. F. Agharebparast and C. V. M. Leung, 'Efficient Fair Queueing with Decoupled Delay-Bandwidth Guarantees,' in Proc. of IEEE GLOBECOM, pp. 2601-2605, 2001
  17. V. Paxson and S. Floyd, 'Wide Area Traffic: The Failure of Poisson Modeling,' IEEE/ACM Trans. on Networking, vol. 3, no. 3, pp. 226-244, June. 1995 https://doi.org/10.1109/90.392383
  18. ITU: US TG 8/1, Radio Communication Study Group, The Radio cdma2000 RTT candidate submission, TR45-5, June98 1998
  19. P. Barford and M. E. Crovella, 'Generating representative workloads for network and server performance evaluation,' Proceedings of ACM SIGMETRICS 98, pp. 151-160, 1998
  20. V. Paxson, 'Empirically Derived Analytic Models of Wide-Area TCP Connections,' IEEE/ACM , vol. 2, no. 4, pp. 316-336, Aug. 1994 https://doi.org/10.1109/90.330413