{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Ch10_RT - Optimizing Power Runtime Circuits and Systems Jan...

Info icon This preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Low Power Design Essentials ©2008 10.1 Jan M. Rabaey Low Power Design Essentials ©2008 Chapter 10 Optimizing Power @ Runtime Circuits and Systems
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Low Power Design Essentials ©2008 10.2 Chapter Outline § Motivation behind run-time optimization § Dynamic voltage and frequency scaling § Adaptive body biasing § General self-adaptation § Aggressive deployment § Power domains and power management
Image of page 2
Low Power Design Essentials ©2008 10.3 Why Run-Time Optimization for Power? § Power dissipation strong function of activity § In many applications, activity various strongly over time: Example 1: Operational load varies dramatically in general purpose computing. Some computations also requires faster response than others. Example 2: The amount of computation to be performed in many signal processing and communication functions (such as compression or filtering) is a function of the input data stream and its properties.. § Optimum operation point in the performance-energy space hence varies over time § Changes in manufacturing, environmental or aging conditions also lead to variable operation points Designs for a single fixed design point are sub-optimal
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Low Power Design Essentials ©2008 10.4 Variable Workload in Media Processing Example: Video Compression [Courtesy: A. Chandrakasan] Typical MPEG IDCT Histogram True also for voice processing, graphics, multimedia and communications
Image of page 4
Low Power Design Essentials ©2008 10.5 Variable Workloads in General-Purpose Computing [Ref: A. Sinha, VLSI’01] Workload traces of three processor styles over 60 sec’s Laptop CPU usage chart File server Workstation Dialup server
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Low Power Design Essentials ©2008 10.6 Adapting to Variable Workloads § Goal: Position design in optimal operational point given required throughput § Useful dynamic design parameters: VDD and VTH Changing transistor sizes dynamically non- trivial § Variable supply voltage most effective for dynamic power reduction
Image of page 6
Low Power Design Essentials ©2008 10.7 Adjusting Only the Clock Frequency § Often used in portable processors § Only reduces power – leaves energy/operation constant Does not save battery life Compute ASAP Delivered Throughput Clock Frequency Reduction Excess throug hput Always high throughput Energy/operation remains unchanged while throughput scales down with f CLK f CLK Redu ced time time [Ref: T. Burd, UCB’01]
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Low Power Design Essentials ©2008 10.8 Dynamic Voltage Scaling (DVS) time Matches execution speed to requirements Minimizes average energy/operation Extends battery life up to one order of magnitude with the exact same hardware! Vary VDD and f CLK based on requested throughput Delivered Throughput [Ref: T. Burd, UCB’01]
Image of page 8
Low Power Design Essentials ©2008 10.9 Flashback: VDD and Throughput 0 .
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern