International Journal of Internet, Broadcasting and Communication

The Institute of Internet, Broadcasting and Communication (한국인터넷방송통신학회)
권호 표지
DOI QR코드

DOI QR Code

FlashEDF: An EDF-style Scheduling Scheme for Serving Real-time I/O Requests in Flash Storage

  • Received : 2018.05.20
  • Accepted : 2018.06.02
  • Published : 2018.08.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, we propose a scheduling scheme that can efficiently serve I/O requests having deadlines in flash storage. The I/O requests with deadlines, namely, real-time requests, are assumed to be issued for streaming services of continuous media. Since a Web-based streaming server commonly supports downloads of HTMLs or images, we also aim to quickly process non-real-time I/O requests, together with real-time ones. For this purpose, we adopt the well-known rate-reservation EDF (RR-EDF) algorithm for determining scheduling priorities among mixed I/O requests. In fact, for the use of an EDF-style algorithm, overhead of task's switching should be low and predictable, as with its application of CPU scheduling. In other words, the EDF algorithm is inherently unsuitable for scheduling I/O requests in HDD storage because of highly varying latency times of HDD. Unlike HDD, time for reading a block in flash storage is almost uniform with respect to its physical location. This is because flash storage has no mechanical component, differently from HDD. By capitalizing on this uniform block read time, we compute bandwidth utilization rates of real-time requests from streams. Then, the RR-EDF algorithm is applied for determining how much storage bandwidth can be assigned to non-real-time requests, while meeting deadlines of real-time requests. From this, we can improve the service times of non-real-time requests, which are issued for downloads of static files. Because the proposed scheme can expand flexibly the scheduling periods of streams, it can provide a full usage of slack times, thereby improving the overall throughput of flash storage significantly.

Keywords

References

  1. Seong-Chae Lim, "A Flash-based B+-Tree using Sibling-Leaf Blocks for Efficient Node Updates and Range Searches," The Journal of the Institute of Internet, Broadcasting and Communication (JIIBC), Vol. 8, No. 3, pp. 12-24, August 2016. DOI: http://dx.doi.org/10.7236/IJIBC.2016.8.3.12
  2. Houssine Chetto and Maryline Chetto, "Some Results of the Earliest Deadline Scheduling Algorithm," IEEE Transactions on Software Engineering, Vol. 15, No. 10, pp. 1261-1269, 1989. DOI: https://doi.org/10.1109/TSE.1989.559777
  3. R. Geist and S. Daniel, “A Continuum of Disk Scheduling Algorithms,” ACM Transactions on Computer Systems, Vol. 5, No. 2, pp. 77-92, 1987. DOI: https://doi.org/10.1145/7351.8929
  4. Byung Joo Kim, "Real-time Fault Detection in Semiconductor Manufacturing Process: Research with Jade S olution Company," The Journal of the Institute of Internet, Broadcasting and Communication (JIIBC), Vol. 9, No. 2, pp. 20-26, 2017. DOI: https://doi.org/10.7236/IJIBC.2017.9.2.20
  5. Stan Park and Kai Shen "FIOS: A Fair, Efficient Flash I/O Scheduler," in Proc. 10th USENIX Conference on File and Storage Technologies, February. 14-17, 2012.
  6. Jaechun No and Sung-soon Park, "Exploiting the Effect of NAND Flash-Memory SSD on File System Design," in Proc. of International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery, October 10-12. 2012. DOI: https://doi.org/10.1109/CyberC.2012.93
  7. Mon-Song Chen, Dilip D. Kandlur, and P. Yu, "Optimization of Grouped Sweeping Scheduling (GSS) with Heterogeneous Multimedia Systems," in Proc. of the ACM Multimedia, August 2-6, 1993. DOI: 10.1145/166266.166293
  8. Kang G. Shin and Yi-Chieh Chang, "A Reservation-Based Algorithm for Scheduling Both Periodic and Aperiodic Real-Time Tasks," IEEE Transactions on Computers, Vol. 44, No. 12, pp. 1405-1419, 1995. DOI: https://doi.org/10.1109/12.477246
  9. C. Ruemmler and J. Wilkes, "An Introduction to Disk Modeling," IEEE Computer, Vol. 27, No. 3, pp. 17-28, March 1994. DOI: https://doi.org/10.1109/2.268881
  10. Hofri Micha, "Disk Scheduling: FCFS vs SSTF Revisited," Communications of the ACM, Vol. 23, No 11, pp. 645-653, 1980. DOI: https://doi.org/10.1145/359024.359034
  11. E.L. Lawler, J.K. Lenstra, A H.G. Rinnooy Kan, and D. B. Shmoys, "The Traveling Salesman Problem: A Guided Tour of Combinatorial," John Wiley & Sons Publications, 1985. DOI: https://doi.org/10.1057/jors.1986.117
  12. T. H. Lin and W. Tarng, "Scheduling Periodic and Aperiodic Tasks in Hard Real-time Computing systems," ACM SIGMETRICS, Vol. 19, No 1, pp. 31-38, 1991. DOI: https://doi.org/10.1145/107972.107976
  13. M. Seltzer, P. Chen, and J. Ousterhout, "Disk Scheduling Revisited," in Proc. of the USENIX Winter 1990, pp. 313-324, December 1990. DOI: https://doi.org/10.1.1.152.5459
  14. Abraham Silberschatz, Peter B. Galvin, and Greg Gagne, Operating System Concepts, 9th edition, Wiley, 2016.
  15. R. K. Abbott and H. Garcia-Molina, "Scheduling I/O Requests with Deadlines: A Performance Evaluation," in Proc. of the Real-Time Systems Symposium, pp. 113-125, December 5-7, 1990. DOI: https://doi.org/10.1109/REAL.1990.128736
  16. E. Balafoutis, M. Paterkakis, and P. Triantallou, “Clustered Scheduling Algorithms for Mixed-Media Disk Workloads in a Multimedia Server,” Cluster Computing Journal, Vol. 6, No. 1, pp. 75-86, 2003. DOI: https://doi.org/10.1023/A:1020923202104
  17. Sungchae Lim, "The Dynamic Sweep Scheme using Slack Time in the Zoned Disk," in Proc. 11st DASFAA, pp. 404-419, April 12-15, 2006. DOI: https://doi.org/10.1007/11733836_29
  18. A.L. Narasimha Reddy, "Improving Latency in an Interactive Video Server," in Proc. of the Intl. Conference on Multimedia Computing and Networking, pp. 108-112, 1997. DOI: http://dx.doi.org/10.1117/12.264287
  19. Samsung SSD 850 Evo Specification, Web URL:https://www.cnet.com/products/samsung-ssd-850-evo/specs/