This Article 
 Bibliographic References 
 Add to: 
Power-Aware Scheduling for AND/OR Graphs in Real-Time Systems
September 2004 (vol. 15 no. 9)
pp. 849-864
Dakai Zhu, IEEE
Daniel Moss?, IEEE Computer Society

Abstract—Power aware computing has become popular recently and many techniques have been proposed to manage processor energy consumption for traditional real-time applications. In this paper, we are concerned mainly with the AND/OR model of real-time applications that have different execution paths consisting of different tasks. The contribution of this paper is twofold. First, we propose a greedy slack stealing algorithm to deal with applications represented by AND/OR graphs and prove its correctness in terms of meeting the timing constraints. Then, using statistical information about the applications, we propose a few variations of speculative scheduling algorithms that intend to save energy by reducing the number of speed changes (and, thus, the overhead) while ensuring that the application meets its timing constraints. Some practical issues are also considered, such as shared memory access contention and idle energy consumption. The performance of the algorithms is analyzed with respect to processor energy savings. The results surprisingly show that the greedy slack stealing scheme is better than some speculative schemes and that the greedy scheme is good enough when a reasonable minimal speed exists in the system or when there are only a few (four to six) voltage/speed levels.

[1] N. AbouGhazaleh, D. Mossé, B.R. Childers, and R. Melhem, Toward the Placement of Power Management Points in Real Time Applications Proc. Workshop Compilers and Operating Systems for Low Power, 2001.
[2] H. Aydin, R. Melhem, D. Mossé, and P. Mejia-Alvarez, Dynamic and Aggressive Scheduling Techniques for Power-Aware Real-Time Systems Proc. 22nd IEEE Real-Time Systems Symp., Dec. 2001.
[3] T.D. Burd and R.W. Brodersen, Energy Efficient CMOS Microprocessor Design Proc. 28th Hawaii Int'l Conf. System Sciences, Jan. 1995.
[4] T.D. Burd, T.A. Pering, A.J. Stratakos, and R.W. Brodersen, A Dynamic Voltage Scaled Microprocessor System IEEE J. Solid-State Circuits, vol. 35, no. 11, pp. 1571-1580, 2000.
[5] D. Burger and T. . Austin, The Simplescalar Tool Set, Version 2.0 Technical Report 1342, Dept. of Computer Science, Univ. of Wisconsin-Madison, June 1997.
[6] A. Chandrakasan, V. Gutnik, and T. Xanthopoulos, Data Driven Signal Processing: An Approach for Energy Efficient Computing Proc. Int'l Symp. Low-Power Electronic Devices, 1996.
[7] A. Chandrakasan, S. Sheng, and R. Brodersen, "Low-Power CMOS Digital Design," IEEE J. Solid-State Circuits, Apr. 1992, pp. 473-484.
[8] M.L. Dertouzos and A.K. Mok, Multiprocessor On-Line Scheduling of Hard-Real-Time Tasks IEEE Trans. Software Eng., vol. 15, no. 12, pp. 1497-1505, 1989.
[9] R. Ernst and W. Ye, Embedded Program Timing Analysis Based on Path Clustering and Architecture Classification Proc. Int'l Conf. Computer-Aided Design (ICCAD '97) pp. 598-604, 1997.
[10] S. Gary, P. Ippolito, G. Gerosa, C. Dietz, J. Eno, and H. Sanchez, Powerpc$603^{TM}$, A Microprocessor for Portable Computers IEEE Design&Test of Computers, vol. 11, no. 4, pp. 14-23, 1994.
[11] D.W. Gillies and J.W.-S. Liu, Scheduling Tasks with AND/OR Precedence Constraints SIAM J. Computing, vol. 24, no. 4, pp. 797-810, 1995.
[12] F. Gruian, System-Level Design Methods for Low-Energy Architectures Containing Variable Voltage Processors Proc. Workshop Power-Aware Computing Systems, Nov. 2000.
[13] F. Gruian, Hard Real-Time Scheduling for Low-Energy Using Stochastic Data and DVS Processors Proc. Int'l Symp. Low Power Electronics and Design, pp. 46-51, 2001.
[14] benchmarks.htm, 2004.
[15] http:/, 2004.
[16] T. Ishihara and H. Yauura, Voltage Scheduling Problem for Dynamically Variable Voltage Processors Proc. Int'l Symp. Low Power Electronics and Design, pp. 197-202, Aug. 1998.
[17] P. Kumar and M. Srivastava, Predictive Strategies for Low-Power RTOS Scheduling Proc. 2000 IEEE Int'l Conf. Computer Design: VLSI in Computers and Processors, Sept. 2000.
[18] P. Kumar and M. Srivastava, Power-Aware Multimedia Systems Using Run-Time Prediction Proc. 14th Int'l Conf. VLSI Design, pp. 64-69, Jan. 2001.
[19] R. Melhem, N. AbouGhazaleh, H. Aydin, and D. Mossé, Power Management Points in Power-Aware Real-Time Systems Power Aware Computing, chapter 7, pp. 127-152, Plenum/Kluwer Publishers, 2002.
[20] R. Mishra, N. Rastogi, D. Zhu, D. Mossé, and R. Melhem, Energy Aware Scheduling for Distributed Real-Time Systems Proc. Int'l Parallel and Distributed Processing Symp., Apr. 2003.
[21] D. Mossé, H. Aydin, B.R. Childers, and R. Melhem, Compiler-Assisted Dynamic Power-Aware Scheduling for Real-Time Applications Proc. Workshop Compiler and OS for Low Power, Oct. 2000.
[22] P. Pillai and K.G. Shin, Real-Time Dynamic Voltage Scaling for Low-Power Embedded Operating Systems Proc. 18th ACM Symp. Operating Systems Principles, Oct. 2001.
[23] V. Raghunathan, P. Spanos, and M.B. Srivastava, Adaptive Power-Fidelity in Energy Aware Wireless Embedded Systems Proc. 21st IEEE Real-Time Systems Symp., Nov. 2000.
[24] J.A. Ratches, C.P. Walters, R.G. Buser, and B.D. Guenther, “Aided and Automatic Target Recognition Based upon Sensory Inputs from Image Forming Systems,” IEEE Trans. Pattern Analysis and Machine Intelligence, vol. 19, no. 9, pp. 1004-1019, Sept. 1997.
[25] D. Shin, S. Lee, and J. Kim, Intra-Task Voltage Scheduling for Low-Energy Hard Real-Time Applications IEEE Design and Test of Computers, Mar. 2001.
[26] P. Yang, C. Wong, P. Marchal, F. Catthoor, D. Desmet, D. Verkest, and R. Lauwereins, Energy-Aware Runtime Scheduling for Embedded-Multiprocessor SOCs IEEE Design and Test of Computers, vol. 18, no. 5, pp. 46-58, Sept./Oct. 2001.
[27] F. Yao, A. Demers, and S. Shenker, A Scheduling Model for Reduced CPU Energy Proc. IEEE Ann. Foundations of Computer Science, pp. 374-382, 1995.
[28] D. Zhu, R. Melhem, and B.R. Childers, Scheduling with Dynamic Voltage/Speed Adjustment Using Slack Reclamation in Multi-Processor Real-Time Systems IEEE Trans. Parallel and Distributed Systems, vol. 14, no. 7, pp. 686-700, 2003.

Index Terms:
Power-aware scheduling, AND/OR, real-time systems.
Dakai Zhu, Daniel Moss?, Rami Melhem, "Power-Aware Scheduling for AND/OR Graphs in Real-Time Systems," IEEE Transactions on Parallel and Distributed Systems, vol. 15, no. 9, pp. 849-864, Sept. 2004, doi:10.1109/TPDS.2004.45
Usage of this product signifies your acceptance of the Terms of Use.