Xiaodong Zhang (张晓东)

Robert M. Critchfield Professor in Engineering Department of Computer Science and Engineering The Ohio State University Columbus, OH 43210 Office phone: (614) 292-2770 Office fax: (614) 292-2911 E-mail: zhang at cse dot ohio-state dot edu URL: http://www.cse.ohio-state.edu/~zhang

Xiaodong Zhang is the Robert M. Critchfield Professor in Engineering, and Chairman of the Department of Computer Science and Engineering at the Ohio State University.

Since 1992, he has established and directed the High Performance Computing and Software Laboratory where he has supervised over 40 graduate students (both MS and Ph.D), post-docs, and visiting scholars. His research interests cover a wide spectrum in the areas of high performance and distributed systems. A common thread among his research projects focuses on fast data accesses and resource sharing with cost- and energy-efficient management at different levels of the memory and storage hierarchies in computer, distributed, and Internet systems. Several technical innovations and research results from his team have been adopted or being developed in commercial products and open source systems with direct impacts to our daily computing operations, including the permutation memory interleaving technique first in the Sun MicroSystems' UltraSPARC IIIi processor for various desktop and server products and then in the Sun's dual-core Gemini Processor, the token thrashing protection mechanism and the Clock-Pro page replacement algorithm for memory management in the NetBSD operating system, and in the Linux Kernel . This list of selected and representative papers reflects his long term research efforts.

Xiaodong Zhang was the Program Director of Advanced Computational Research at the National Science Foundation, 2001-2004. He is the associate Editor-in-Chief of IEEE Transactions on Parallel and Distributed Systems, and is also serving on the Editorial Boards of IEEE Transactions on Computers, IEEE Micro, and Journal of Parallel and Distributed Computing. He is an organizer and a lecturer of the Dragon Star Lecture Program offering advanced research classes of computer science and engineering in many Chinese universities for thousands of talented graduate students and young faculty every year.

Xiaodong Zhang received his Ph.D. in Computer Science from the University of Colorado at Boulder in 1989, and his B.S. in Electrical Engineering from Beijing Polytechnic University.

Xiaodong Zhang completed his Master thesis of computer science in Colorado, under the direction of Ralph Slutz (1917-2005), who was a world-class scholar and a computer pioneer.

Selected Publications with Impact on Advanced Computer Systems

• ``A permutation-based page interleaving scheme to reduce row-buffer conflicts and exploit data locality", Proceedings of the 33rd Annual International Symposium on Microarchitecture, (Micro-33), Monterey, California, December 10-13, 2000. pp. 32-41. (with Z. Zhang and Z. Zhu).
  • The permutation technique in this paper has been adopted in the Sun UltraSPARC IIIi processor.
  • An acknowledgement letter from the Sun MicroSystems Inc..
  • The permutation technique and its effectiveness are described in the Memory Interleaving section in a Sun Blade Server Technical Manual.
  • The permutation technique has also been used in the Sun's first dual-core processor Gemini, and is reported in this IEEE Micro paper.
  • The permutation technique is introduced in book Memory Systems: Cache, DRAM, Disk by B. Jacob, S. Ng, and D. Wang.
  • The results in this paper have also been used to support several new memory inventions issued by US Patents, such as a programmable DRAM address mapping technique by Hewlett Packard for fast memory systems, and a low power DRAM design by Freescale Semiconductor Inc. as their embedded memory in many intelligent devices.

• ``Token-ordered LRU: an effective page replacement policy and its implementation in Linux systems", Performance Evaluation, Vol. 60, Issue 1-4, 2005, pp. 5-29. (with S. Jiang).
  • The token algorithm in this paper has been adopted in Linux Kernel version 2.6. called "swap token"
  • The token algorithm (swap token) is also presented in a section in the widely used Linux Kernel book Understanding the Linux Kernel (3rd edition) by D. P. Bovet and M. Casati.
  • The insights into system thrashing caused by ``false LRU pages" presented in this paper are also quoted in the Linux Memory Management Wiki.
  • The source code of "swap token" in Linux kernel implemented by Rik van Riel is archived in Cross-Referening Linux Library.
  • A "preemtive swap token" patch is available in Linux kernel 2.6.

• ``CLOCK-Pro: an effective improvement of the CLOCK replacement", Proceedings of 2005 USENIX Annual Technical Conference (USENIX'05), Anaheim, CA, April 10-15, 2005, pp. 323-336. (with F. Chen, and S. Jiang).
  • A technical article about Clock-Pro's Linux kernel implementation by Jonathan Coebet in Linux Weekly News (www.lwn.net).
  • Clock-pro has been adopted in NetBSD. The kernel source code developed by Yamamoto Takash from VA Linux Systems (Japan) is archived in FreeBSD/Linux Kernel Cross Reference Library, and is open for public usage.
  • The Linux Kernel Develpment Page of Clock-Pro.
  • Clock-Pro patches in 2.6.12 developed by Rik van Riel from the Red Hat, Inc.
  • An alternative Linux kernel implementation of Clock-Pro by Peter Zijlstra.
  • Advanced Page Replacement Projects established by the Linux Memory Management Development Team.
  • It has been implemented in Apache Derby (an open source relational database) by a 2006 Google Summer Code project: Derby Cache Manager, which shows its effectiveness in this paper.

Selected Recent Publications

• Computer Systems
  • ``Gaining insights into multicore cache partitioning: bridging the gap between simulation and real systems", Proceedings of the 14th International Symposium on High Performance Computer Architecture (HPCA'08), Salt Lake City, Utah, February 16-20, 2008. (with X. Ding, J. Lin, Q. Lu, P. (Saday) Sadayappan, and Z. Zhang).

  • ``DiskSeen: exploiting disk layout and access history to enhance I/O prefetch", Proceedings of 2007 USENIX Annual Technical Conference (USENIX'07), Santa Clara, June 17-22, 2007. (with F. Chen, K. Davis, X. Ding, and S. Jiang).

  • ``SmartSaver: turning flash drive into a disk energy saver for mobile computers" Proceedings of the 11th ACM International Symposium on Low Power Electronics and Design (ISLPED'06), Tegernsee, Germany, October 4-6, 2006. (with F. Chen and S. Jiang).

  • ``DULO: an effective buffer cache management scheme to exploit both temporal and spatial localities", Proceedings of the 4th USENIX Conference on Files and Storage Technologies (FAST'05), San Francisco, CA, December 14-16, 2005. (with F. Chen, X. Ding, S. Jiang, and E. Tan).

• Distributed and Networking Systems
  • ``PSM-Throttling: minimizing energy comsumption for bulk data communications in WLANs", Proceedings of the 15th International Conference on Network Protocols (ICNP'07), Beijing, China, October 16-19, 2007. (with S. Chen, L. Guo, and E. Tan).

  • ``SProxy: a caching infrastructure for Internet streaming", IEEE Transactions on Multimedia, Vol. 9, Issue. 5, 2007, pp. 1062-1072. (with S. Chen, B. Shen, and S. Wee).

  • ``SCAP: Smart Caching in wireless Access Points to improve P2P streaming", Proceedings of the 27th International Conference on Distributed Computing Systems (ICDCS'07), Toronto, Canada, June 25-29, 2007. (with S. Chen, L. Guo, and E. Tan).

  • ``Does Internet media traffic really follow Zipf-like distribution?", (an extended abstract), Proceedings of ACM 2007 International Conference on Measurement and Modeling of Computer Systems (SIGMETRICS'07), San Diego, June 12-16, 2007. (with S. Chen, L. Guo, E. Tan, and Z. Xiao).

  • ``Delving into Internet streaming media delivery: a quality and resource utilization perspective", Proceedings of ACM SIGCOMM Internet Measurement Conference (IMC'06), Rio de Janeiro, Brazil, October 25-27, 2006. (with S. Chen, L. Guo, O. Spatscheck, E. Tan, and Z. Xiao)

  • ``ASAP: an AS-Aware Peer-relay protocol for high quality VoIP", Processings of the 26th International Conference on Distributed Computing Systems (ICDCS'06), Lisbon, Portugal, July 4-7, 2006. (with L. Guo and S. Ren).

  • ``Measurement, analysis, and modeling of BitTorrent-like systems"", Proceedings of ACM SIGCOMM Internet Measurement Conference (IMC'05), Berkeley, CA, October 19-21, 2005. (with S. Chen, X. Ding, L. Guo, E. Tan, and Z. Xiao)

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  More Publications

  • Selected and Representative Papers.

  • Publications sorted by years since 1994.

  • Publications sorted by topics since 1994.

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  Current Research Projects

  • Core Computer Systems
    • Software and Hardware Methods for Memory Performance Improvement

    • Memory Management, Caching, and Prefetching for I/O Performance Improvement

  • High-end Computer Systems
    • Effective Global Memory Sharing and Coordination in High-end Cluster Systems

  • Distributed and Internet Systems
    • Improving Performance and Reliability in Internet Services

    • Gaining Insights into Interent Streaming Patterns and Improving Internet Delivering Systems

    • System/Application Designs, Optimizations and Implementations on Overlay Networks

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  Graduated Ph.D.'s

  • Yong Yan, May 1998, (Research Scientist, Hewlett Packard Laboratories, Palo Alto, California),
    Ph.D. Dissertation: Exploiting Multiprocessor Cache Locality at Run-Time.

  • Zhao Zhang, June 2002, (Assistant Professor of Electrical and Computer Engineering, Iowa State University),
    Ph.D. Dissertation: Software and Hardware Methods for Memory Access Latency Reduction on ILP Processors.

  • Li Xiao, July 2002, (Assistant Professor of Computer Science and Engineering, Michigan State University),
    Ph.D. Dissertation: Adaptive and Secured Resource Management in Distributed and Internet Systems.

  • Zhichun Zhu, July 2003, (Assistant Professor of Electrical and Computer Engineering, University of Illinois at Chicago),
    Ph.D. Dissertation: Power Considerations for Memory-Related Microarchitecture Designs.

  • Song Jiang, June 2004, (Assistant Professor of Electrical and Computer Engineering , Wayne State University),
    Ph.D. Dissertation: Efficient Caching Algorithms for Memory Management in Computer Systems.

  • Songqing Chen, July 2004, (Assistant Professor of Computer Science, George Mason University),
    Ph.D. Dissertation: Building Internet Caching Systems for Multimedia Content Delivery.

  • Xin Chen, April 2005, (Member of Technical Staff, AskJeeves Inc.),
    Ph.D. Dissertation: Internet Techniques of Data Prefetching, Replication, and Consistency.

  • Lei Guo, November 2007, (Senior Member of Technical Staff, Yahoo!),
    Ph.D. Dissertation: Insights into Access Patterns of Internet Media Systems: Measurements, Analysis, and System Design.

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  Current Students

  • Feng Chen (Ph.D. Candidate)

  • Xiaoning Ding (Ph.D. Candidate)

  • Shuang Liang (Ph.D. Candidate)

  • Shansi Ren (Ph.D. Candidate)

  • Enhua Tan (Ph.D. Candidate)

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  Professional Activities

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  Seeing is Believing

  Traveling has been an important part of education in my life. Here are selected photos I took in different countries besides Mainland China and USA.

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