时间：6月9日（周四）下午3：00

地点：海韵教学楼201

Title: Challenges and Future Trend in Multicore/Manycore Computer Architecture Research

Speaker: Hong Jiang

Department of Computer Science & Engineering，University of Nebraska-Lincoln

Computer systems and architecture research is at a historical crossroad, with the emerging multicore/manycore architectures rapidly dominating the R&D in computer architecture and a number of daunting challenges facing the design, development and application of such architectures. In this talk, I will first give an overview of the landscape of multicore/manycore architecture research and challenges and focus on the effort to overcome one of the several challenges, namely, the “memory wall”, by introducing two of research proposals from my research group on optimizing the last level cache (LLC) management of the multicore/manycore memory hierarchy. The first proposal, called SNUG (Set-level Non-Uniformity identifier and Grouper), is a novel LLC cache design to exploit the set-level non-uniformity of capacity demand to further enhance the effectiveness of cooperative caching. By utilizing a per-set shadow tag array and saturating counter, SNUG can identify whether a set should either spill or receive blocks; by  using an index-bit flipping scheme, SNUG can group peer sets for spilling and receiving in an flexible way, capturing more opportunities for cooperative caching. The second proposal, called STEM (Spatiotemporal Management), is a novel adaptive scheme that concurrently and dynamically manages both spatial and temporal dimensions of capacity demands at the set level. In STEM, a set-level monitor captures the temporal and spatial capacity demands of individual working sets and judiciously pairs off sets with complementary capacity demands so that the underutilized set in each pair can cooperatively cache the other’s victim blocks. The controller also decides on the best temporal sharing patterns for the coupled sets in the event of inter-set space sharing. Further, if the LLC controller cannot find a complementary set for a particular set, STEM can still decide on the best set-level replacement policy for it.

A Short Biography of Hong Jiang
Hong Jiang received the B.Sc. degree in Computer Engineering in 1982 from Huazhong University of Science and Technology, Wuhan, China; the M.A.Sc. degree in Computer Engineering in 1987 from the University of Toronto, Toronto, Canada; and the PhD degree in Computer Science in 1991 from the Texas A&M University, College Station, Texas, USA. Since August 1991 he has been at the University of Nebraska-Lincoln, Lincoln, Nebraska, USA, where he served as Vice Chair of the Department of Computer Science and Engineering (CSE) from 2001 to 2007 and is Professor of CSE.
His present research interests include computer architecture, computer storage systems and parallel I/O, parallel/distributed computing, cluster and Grid computing, performance evaluation, real-time systems, middleware, and distributed systems for distance education. He serves as an Associate Editor of the IEEE Transactions on Parallel and Distributed Systems. He has over 170 publications in major journals and international Conferences in these areas, including IEEE-TPDS, IEEE-TC, JPDC, ISCA, MICRO, FAST, ICDCS, IPDPS, OOPLAS, ECOOP, SC, ICS, HPDC, ICPP, etc., and his research has been supported by NSF, DOD and the State of Nebraska. Dr. Jiang is a Senior Member of IEEE, a member of ACM.