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Robust Processing Rate Allocation for Proportional Slowdown Differentiation on Internet Servers
August 2005 (vol. 54 no. 8)
pp. 964-977
Xiaobo Zhou, IEEE Computer Society
A desirable behavior of an Internet server is that a request's queuing delay depends on its service time in a linear fashion. Measuring the quality of service in terms of slowdown, the ratio of a request's queuing delay to its service time, provides a simple way to attain the objective. Moreover, it treats client requests equally regardless of their service time, whereas response time favors requests that need more processing resources. In this paper, we propose a proportional slowdown differentiation (PSD) service model on Internet servers. It aims to maintain prespecified slowdown ratios between different classes of client requests. To provide PSD services, we first derive a closed-form expression of the expected slowdown in an M/G/1 FCFS queuing system with a typical heavy-tailed service time distribution, the bounded Pareto distribution. Based on the closed-form expression, we design a queuing-theoretic strategy of processing-rate allocation. The rate allocation is realized by deploying a virtual server for each class. Simulation results show that the strategy can provide controllable PSD services on Internet servers. It, however, comes along with large variance and weak predictability due to the dynamics of Internet traffic. To address these issues, we design an integral feedback controller and integrate it into the queuing-theoretic strategy. Simulation results demonstrate that the integrated strategy is robust and can deliver predictable PSD services at a superior fine-grained level. We modified the Apache Web server with an implementation of the integrated processing-rate allocation strategy. Experimental results further demonstrate its effectiveness and feasibility in practice.

[1] T.F. Abdelzaher, K.G. Shin, and N. Bhatti, “Performance Guarantees for Web Server End-Systems: A Control-Theoretical Approach,” IEEE Trans. Parallel and Distributed Systems, vol. 13, no. 1, pp. 80-96, Jan. 2002.
[2] J. Almeida, M. Dabu, A. Manikutty, and P. Cao, “Providing Differentiated Levels of Service in Web Content Hosting,” Proc. ACM SIGMETRICS Workshop Internet Server Performance, pp. 91-102, 1998.
[3] M. Arlitt and T. Jin, “A Workload Characterization Study of the 1998 World Cup Web Site,” IEEE Network, vol. 14, no. 3, pp. 30-37, May-June 2000.
[4] M. Arlitt and C.L. Williamson, “Internet Web Servers: Workload Characterization and Performance Implications,” IEEE/ACM Trans. Networking, vol. 5, no. 5, pp. 631-645, Oct. 1997.
[5] P. Barford and M. Crovella, “Generating Representative Web Workloads for Network and Server Performance Evaluation,” Proc. ACM Sigmetrics, pp. 151-160, 1998.
[6] M.A. Bender, S. Chakrabarti, and S. Muthukrishnan, “Flow and Stretch Metrics for Scheduling Continuous Job Streams,” Proc. ACM-SIAM Symp. Discrete Algorithms, pp. 270-279, 1998.
[7] S. Blake, D. Black, M. Carlson, E. Davies, Z. Wang, and W. Weiss, “An Architecture for Differentiated Services,” IETF, RFC 2475, Dec. 1998.
[8] C. Chekuri, A. Goel, S. Khanna, and A. Kumar, “Multi-Processor Scheduling to Minimize Flow Time with $\epsilon$ Resource Augmentation,” Proc. ACM Symp. Theory of Computing, pp. 363-372, 2004.
[9] X. Chen and P. Mohapatra, “Performance Evaluation of Service Differentiating Internet Servers,” IEEE Trans. Computers, vol. 51, no. 11, pp. 1368-1375, Nov. 2002.
[10] L. Cherkasova and P. Phaal, “Session-Based Admission Control: A Mechanism for Peak Load Management of Commerical Web Sites,” IEEE Trans. Computers, vol. 51, no. 6, pp. 669-685, June 2002.
[11] M.E. Crovella, R. Frangioso, and M. Harchol-Balter, “Connection Scheduling in Web Servers,” Proc. USENIX Symp. Internet Technologies and Systems, 1999.
[12] M.E. Crovella, M. Harchol-Balter, and C.D. Murta, “Task Assignment in a Distributed System: Improving Performance by Unbalancing Load,” Proc. ACM Sigmetrics, pp. 268-269, 1998.
[13] C. Dovrolis, D. Stiliadis, and P. Ramanathan, “Proportional Differentiated Services: Delay Differentiation and Packet Scheduling,” IEEE/ACM Trans. Networking, vol. 10, no. 1, pp. 12-26, 2002.
[14] L. Eggert and J. Heidemann, “Application-Level Differentiated Services for Web Servers,” World Wide Web J., vol. 2, no. 3, pp. 133-142, 1999.
[15] D.G. Feitelson and L. Rudolph, “Metrics and Benchmarking for Parallel Job Scheduling,” Proc. Int'l Parallel Processing Symp. Workshop Job Scheduling Strategies for Parallel Processing, pp. 1-24, 1998.
[16] G.F. Franklin, J.D. Powell, and A. Emami-naeini, Feedback Control of Dynamic Systems, fourth ed. Prentice Hall, 2002.
[17] M. Harchol-Balter, “Task Assignment with Unknown Duration,” J. ACM, vol. 49, no. 2, pp. 260-288, 2002.
[18] M. Harchol-Balter, B. Schroeder, N. Bansal, and M. Agrawal, “Size-Based Scheduling to Improve Web Performance,” ACM Trans. Computer Systems, vol. 21, no. 2, pp. 207-233, May 2003.
[19] Y. Huang and R. Guérin, “A Simple FIFO-Based Scheme for Differentiated Loss Guarantees,” Proc. Int'l Workshop Quality of Service, pp. 96-105, 2004.
[20] S.C. Lee, J.C. Lui, and D.K. Yau, “A Proportional-Delay Diffserv-Enabled Web Server: Admission Control and Dynamic Adaption,” IEEE Trans. Parallel and Distributed Systems, vol. 15, no. 5, pp. 385-400, May 2004.
[21] W.E. Leland, M.S. Taqqu, W. Willinger, and D.V. Wilson, “On the Self-Similar Nature of Ethernet Traffic (Extended Version),” IEEE/ACM Trans. Networking, vol. 2, no. 1, pp. 1-15, Feb. 1994.
[22] M.K. Leung, J.C. Lui, and D.K. Yau, “Adaptive Proportional Delay Differentiated Services: Characterization and Performance Evaluation,” IEEE/ACM Trans. Networking, vol. 9, no. 6, pp. 801-817, Dec. 2001.
[23] Z. Liu, N. Niclausse, and C. Jalpa-Villanueval, “Traffic Model and Performance Evaluation of Web Servers,” Performance Evaluation, vol. 46, nos. 2-3, pp. 77-100, Oct. 2001.
[24] C. Lu, T.F. Abdelzaher, J.A. Sankovic, and S.H. Son, “A Feedback Control Approach for Guaranteeing Relative Delays in Web Servers,” Proc. IEEE Real-Time and Embedded Technology and Applications Symp., 2001.
[25] Y. Lu, T.F. Abdelzaher, C. Lu, L. Sha, and X. Liu, “Feedback Control with Queuing-Theoretic Prediction for Relative Delay Guarantees in Web Servers,” Proc. IEEE Real-Time and Embedded Technology and Applications Symp., pp. 208-217, 2003.
[26] T. Nandagopal, N. Venkitaraman, R. Sivakumar, and V. Bharghavan, “Delay Differentiation and Adaptation in Core Stateless Networks,” Proc. IEEE Infocom, pp. 421-430, 2000.
[27] K. Nichols, V. Jacobson, and L. Zhang, “A Two-Bit Differentiated Services Architecture for the Internet,” IETF, RFC 2638, July 1999.
[28] D.P. Olshefski, J. Nieh, and E. Nahum, “ksniffer: Determining the Remote Client Perceived Response Time from Live Packet Streams,” Proc. Usenix Operating Systems Design and Implementation, 2004.
[29] A.K. Parekh and R.G. Gallager, “A Generalized Processor Sharing Approach to Flow Control in Integrated Services Networks: The Single-Node Case,” IEEE/ACM Trans. Networking, vol. 1, no. 3, pp. 344-357, 1993.
[30] S. Parekh, N. Gandhi, J. Hellerstein, D. Tilbury, T. Jayram, and J. Bigus, “Using Control Theory to Achieve Service Level Objectives in Performance Management,” J. Real-Time Systems, pp. 127-141, 2002.
[31] V. Paxson and S. Floyd, “Wide Area Traffic: The Failure of Possion Modeling,” IEEE/ACM Trans. Networking, vol. 3, no. 3, pp. 226-244, June 1995.
[32] L. Sha, X. Liu, Y. Lu, and T.F. Abdelzaher, “Queuing Model Based Network Server Performance Control,” Proc. IEEE Real-Time Systems Symp., pp. 81-90, 2002.
[33] J. Wei, Q. Li, and C. Xu, “VirtualLength: A New Packet Scheduling Algorithm for Proportional Delay Differentiation,” Proc. Int'l Conf. Computer Comm. and Network, pp. 331-336, 2003.
[34] J. Wei, C. Xu, and X. Zhou, “A Robust Packet Scheduling Algorithm for Proportional Delay Differentiation Services,” Proc. IEEE Globecom, 2004.
[35] J. Wei and C. Xu, “A Self-Tuning Fuzzy Control Approach for End-to-End QoS Guarantees in Web Servers,” Proc. Int'l Workshop Quality of Service, 2005.
[36] X. Zhou, J. Wei, and C. Xu, “Processing Rate Allocation for Proportional Slowdown Differentiation on Internet Servers,” Proc. Int'l Parallel and Distributed Processing Symp., 2004.
[37] X. Zhou and C. Xu, “Harmonic Proportional Bandwidth Allocation and Scheduling for Service Scheduling on Streaming Servers,” IEEE Trans. Parallel and Distributed Systems, vol. 15, no. 9, pp. 835-848, Sept. 2004.
[38] H. Zhu, H. Tang, and T. Yang, “Demand-Driven Service Differentiation in Cluster-Based Network Servers,” Proc. IEEE Infocom, pp. 679-688, 2001.

Index Terms:
Index Terms- Quality of Service, slowdown, queuing theory, feedback control, rate allocation.
Jianbin Wei, Xiaobo Zhou, Cheng-Zhong Xu, "Robust Processing Rate Allocation for Proportional Slowdown Differentiation on Internet Servers," IEEE Transactions on Computers, vol. 54, no. 8, pp. 964-977, Aug. 2005, doi:10.1109/TC.2005.135
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