UCLA Computer Science Department CS 259 Current Topics  in Computer Science: System Design/Architecture Energy-Efficient Computer Systems Spring 2011 Class: MW 10-12, 1003 Moore Hall

Prof. Milos D. Ercegovac 4731-H Boelter Hall 825-5414 e-mail: milos@cs.ucla.edu web page: http://www.cs.ucla.edu/~milos Office hours: MW2-3pm, or by appointment

We discuss power/energy problems in computer systems and hardware, algorithm, and software approaches to deal with these problems  in the design of processors, arithmetic units, memories, and caches. We also study roles of OS, compiler optimizations and application-software in power management.  Examples of systems  discussed include power-efficient multiprocessors, reconfigurable systems, servers, embedded systems, mobile devices, and graphics processors. Course material: several  books, listed below. These are available online via UCLA EMS Library. Selected papers will be provided on the class CourseWeb site. Class Lecture/Presentation Viewgraphs:posted on the class CourseWeb site. Grading: The grading is based on class presentations (30%), discussions and participation (10%), and a project (60%). Presentations and projects will be peer-reviewed. Prerequisites: A familiarity with digital design, computer architecture, and system software utilities such as compilers and operating systems, is desirable.

General Lectures
1. Introduction	Power/energy problems: sources. Basic concepts:power, energy, power dissipation, power density, power efficiency, energy efficiency. Energy-delay tradeoff. Power management. Overview  of optimization approaches: digital circuit level, processor architecture, primary memory and caches. Algorithms, compilers and operating systems. [Readings: Rabaey Ch. 3, Panda Ch. 2]
2. Circuits and logic design	Power consumption in CMOS circuits. Dynamic  power: switching and short circuit power. Static power: leakage power. Techniques for reducing dynamic power:  gate sizing,  signal transitions,  FSM state encoding , clock gating, voltage and frequency scaling. Techniques for reducing static power.  Techniques for reducing leakage power: multiple supply voltage, multiple threshold voltage, adaptive body biasing, transistor stacking, power gating. [Readings: Rabaey Ch. 4]
3.  Architecture, algorithms and systems	Architecture/system tradeoff space. Use of concurrency to improve energy efficiency. Energy-delay space. Matching computations and architecture: Application-specific processors. Arithmetic: Reducing signal transition frequency. Signal gating. Adders, accumulators, multipliers, dividers. Better-than-worst-case design. Approximate arithmetic. [Readings: Rabaey Ch. 5]
4. Memories and caches	Embedded static random access memories (SRAM). Memory organization. Power in cell array, for read access,  and for write access. Power-efficient SRAM and cache architectures. Scratch pad memory (SPM). Data placement in SPM. Optimizing power in standby. [Readings: Rabaey Ch. 7 and Ch. 9, Panda Ch. 4]
5. OS and compilers	OS optimizations: Power management policies. Advanced configurations and power interface (ACPI). Dynamic voltage and frequency scaling (DVFS). Compiler optimizations: loop transformations, instruction encoding, instruction scheduling, power gating. Dynamic translation and recompilation. [Readings: Rabaey Ch. 5, Panda Ch. 5]

Student Lectures: After  two weeks of  the instructor's lectures on general topics,  the  classes will have the following format:  (i) an introduction by instructor, (ii) students' short lectures and  discussions by assigned students. For a class lecture, you will  select a topic, consult with instructor, and prepare a 25-minute presentation and a handout. The topic can be from the recommended books, selected papers.

Books

Low Power Design Essentials by Jan Rabaey, Springer 2009. Power-efficient System Design  by Preeti R. Panda, Aviral Shrivastava, B.V.N. Silpa, and Krishnaiah Gummidipudi, Springer 2010. Designing Embedded Processors: A Low Power Perspective Edited by J. Henkel and S. Parameswaran, Springer 2007. Ultra-Low Energy Domain-Specific Instruction-Set Processors by Francky Catthoor et al., Springer  2010. Low Power Methodology Manual For System-on-Chip Design by Michael Keating, David Flynn, Robert Aitken, Alan Gibbons, and Kaijian Shi, Springer 2007. Closing the Power Gap Between ASIC & Custom: Tools and Techniques for Low Power Design by David Chinnery and Kurt Keutzer, Springer 2007. CAD Algorithms, Methods and Tools for Low-Power Circuits and Systems,  Edited by E. Macii IEEE Technological Survey, 2006.

Conference proceedings	ACM/IEEE International Symposium on Low Power Electronics and Design (ISLPED) International Symposium on Computer Architecture (ISCA) MICRO International Conference on Computer-Aided Design (ICCAD) Design Automation Conference (DAC) International Symposium on Quality Electronic Design (ISQED)
Journals and magazines	IEEE Transactions on Computers IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems IEEE Transactions on Very Large Scale Integration (VLSI) Systems IEEE Journal on Solid State Circuits ACM Transactions on Design Automation of Electronic Systems (TODAES) Journal of VLSI Signal Processing IEEE Micro

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