"Two Scalable Core Architectures for Power-Constrained CMPs"

David A. Wood, Professor, University of Wisconsin, Madison

October 31st (Monday), 3:30pm
Computer Science Conference Room (HFH, Rm 1132)

Chip Multiprocessors (CMPs) are now commodity hardware, but commoditization of parallel software remains elusive. In the near term, the current trend of increased core-per-socket count will continue, despite a lack of parallel software. Future CMPs must deliver thread-level parallelism when software provides threads to run, but must also continue to deliver high single-thread performance–via instruction-level and memory-level parallelism–to mitigate sequential bottlenecks and/or to guarantee service-level agreements. However, power limitations will prevent conventional cores from exploiting both simultaneously.

The Wisconsin Multifacet project has recently developed two alternative scaleable core architectures, which can scale their execution logic up to run single threads fast, or down to run multiple threads within a fixed power budget. WiDGET (Wisconsin Decoupled Grid Execution Tiles) decouples thread context management from a sea of simple execution units. WiDGET’s decoupled design provides flexibility to alter resource allocation for a particular power-performance target while turning off unallocated resources. Forwardflow dynamically builds an explicit internal dataflow representation from a conventional instruction set architecture, using forward dependence pointers to guide instruction wakeup, selection, and issue. Forwardflow’s backend is organized into discrete units that can be individually (de-)activated, allowing each core’s performance to be scaled by system software at the architectural level.

About David A. Wood:

Professor David A. Wood is a Professor in the Computer Sciences Department at the University of Wisconsin, Madison and has a joint appointment in Electrical and Computer Engineering.

Dr. Wood was named an ACM Fellow (2005) and IEEE Fellow (2004), received the University of Wisconsin's H.I. Romnes Faculty Fellowship (1999), received the National Science Foundation's Presidential Young Investigator award (1991), and earned his Ph.D. in Computer Sciences from the University of California, Berkeley (1990). Dr. Wood is Chair of ACM Special Interest Group on Computer Architecture (SIGARCH), Area Editor (Computer Systems) of ACM Transactions on Modeling and Computer Simulation, is Associate Editor of ACM Transactions on Architecture and Compiler Optimization, served as Program Committee Chairman of ASPLOS-X (2002), and has served on numerous program committees. Dr. Wood is an ACM Fellow, an IEEE Fellow, and a member of the IEEE Computer Society. Dr. Wood has published over 70 technical papers and is an inventor on twelve U.S. and International patents.

Dr. Wood co-leads the Wisconsin Multifacet Project with Prof. Mark Hill which is exploring techniques for improving the availability, designability, programmability, and performance of commercial multiprocessor and chip multiprocessor servers.

Hosted by: Computer Engineering Program, Director Fred Chong