Reducing the energy usage of office applications
1 / 25

- PowerPoint PPT Presentation

  • Updated On :

Reducing the Energy Usage of Office Applications. Eyal de Lara Dan S. Wallach Willy Zwaenepoel Rice University. Jason Flinn M. Satyanarayanan Carnegie Mellon University. Motivation. Energy is a vital resource in mobile computing Previous work shows value of energy-aware adaptation

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about '' - ostinmannual

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Reducing the energy usage of office applications l.jpg

Reducing the Energy Usage of Office Applications

Eyal de Lara

Dan S. Wallach

Willy Zwaenepoel

Rice University

Jason Flinn

M. Satyanarayanan

Carnegie Mellon University

Motivation l.jpg

  • Energy is a vital resource in mobile computing

  • Previous work shows value of energy-aware adaptation

    • Reduce fidelity

    • Requires modification to application source code

      Can this work without source code?

      Middleware-based proxy can help!

Validation l.jpg

  • Common office applications can be made energy-aware

    • Puppeteer uses well-defined data format and API

    • Modified PowerPoint to reduce energy usage

  • Preview of results:

    • Energy reductions up to 49% for some activities

    • Proxy approach modifies PowerPoint behavior

    • Other opportunities for increased energy-efficiency

Outline l.jpg

  • Motivation

  • Background: Puppeteer

  • Energy benefits of adaptation

  • Other opportunities for extending battery lifetime

  • Future work and conclusions

Component based adaptation l.jpg



on save






on save

Component-Based Adaptation

Documents often stored on a central file server

Must download and edit on a mobile client

Can save time and energy by editing a low-fidelity version



Puppeteer l.jpg








Server proxy parses and transcodes documents

Client proxy uses external API to interact with PowerPoint

How much energy can component-based adaptation save?


Uses well-defined data formats, exported APIs






Measuring application energy usage l.jpg





Measuring Application Energy Usage

Digital multimeter samples laptop power use

Applications mark start and end of events

Energy usage is integral of power over time

Benchmark presentations l.jpg
Benchmark Presentations

Benchmark consists of 10 PowerPoint presentations

Size and effect of distillation vary

Experiment loading documents l.jpg
Experiment: Loading Documents

  • Client: IBM 560X laptop with 2 Mb/s wireless network

  • Server: Wall-powered desktop

  • Client runs NT, PowerPoint, Puppeteer client proxy

  • Server runs NT, Apache, Puppeteer server proxy

  • Measure energy used to load documents:

    • From Apache (native mode)

    • Using Puppeteer (distilling out multimedia data)

Energy benefit for loading documents l.jpg


Energy Benefit for Loading Documents

Average energy usage reduced 40%!

With simple filter, energy usage reduced 49%!

Experiment editing documents l.jpg
Experiment: Editing Documents

  • Load documents on the client

  • Measure energy needed to page through document for:

    • Full-quality version

    • Distilled version

Energy benefit for editing documents l.jpg
Energy Benefit for Editing Documents

Distillation reduces paging energy 13%

Benefit less on subsequent traversals of document

Reducing computational fidelity l.jpg
Reducing Computational Fidelity

How much energy is used by background activities?

Not a lot to be gained by disabling most activities . . .

But, the Office Assistant is quite expensive!

Experiment autosave frequency l.jpg
Experiment: Autosave Frequency

  • Documents are saved on the client

    • Autosaves over network prohibitively expensive!

    • Reducing frequency saves energy

    • But, greater possibility of losing data!

  • Measure additonal power savings for autosave frequency:

    • One minute (very expensive)

    • Five minutes (less expensive)

    • No autosave (optimal savings)

Effect of autosave frequency l.jpg
Effect of Autosave Frequency

Average energy reduction of 11%

Outline16 l.jpg

  • Motivation

  • Puppeteer: component-based adaptation

  • Energy benefits of adaptation

  • Other opportunities for extending battery lifetime

  • Future work and conclusions

Comparing puppeteer and native mode l.jpg
Comparing Puppeteer and Native Mode

Mystery: Why does Puppeteer take less time and energy to load a presentation than native mode?

Effect of network power management l.jpg
Effect of Network Power Management

  • Hypothesis: power management slows down transfer

    • Network receiver disabled for 100 ms. periods

    • Wireless bandwidth 2 Mb/s

    • In effect, a high bandwidth*delay product (25 KB)

    • Socket buffer and receive window only 8 KB

    • Native mode uses only 1 connection

    • Puppeteer uses up to 4 connections

      Verified this hypothesis by measuring:

    • With 64KB buffer sizes

    • Without network power management

Network power management results l.jpg
Network Power Management Results

With 64 KB buffers, native mode uses 26% less energy

Disabling power management saves additional 18%

Disk power management l.jpg


Disk spinning = Wasted Energy

Disk Power Management

Disk power management predicts periods of inactivity

After autosave, waits for additional activity

Disk in high-power state for 30 seconds

Transparent power management l.jpg
Transparent Power Management

  • Applications and power mgmt. layer don’t communicate

    • Power management balances performance & energy

    • Tries to minimize impact on applications

    • Difficult without knowledge of application activity

      Transparent power management can help!

    • Applications provide hints about their activities

    • OS combines hints from all applications

    • OS chooses the optimal power mgmt. settings


Power Mgmt.










Powerpoint and power management l.jpg
PowerPoint and Power Management

  • Puppeteer could provide PM hints for PowerPoint

  • Signals start and end of large transfers

    • Power management disabled during transfers

    • Uses 18% less energy, 22% less time

  • Signals when regular autosave is occurring

    • Can spin-down disk immediately after autosave

    • Uses 4% less energy

Outline23 l.jpg

  • Motivation

  • Puppeteer: component-based adaptation

  • Energy benefits of adaptation

  • Other opportunities for extending battery lifetime

  • Future work and conclusions

Future work l.jpg
Future Work

  • System support for energy-aware applications

    • Currently open-source implementation (Linux)

    • Monitors supply and demand, adjusts fidelity

    • Port to closed-source environment (Windows)

      Transparent power management

    • Create API for expressing application hints

    • Develop algorithms that combine hints

    • Investigate other hardware devices (CPU)

Conclusions l.jpg

  • No one magic bullet for reducing PowerPoint energy use

  • But, many opportunities for significant energy reduction

    • Reducing data fidelity

    • Reducing computational fidelity

    • Transparent power management

      Puppeteer provides a mechanism for achieving reductions

    • Proxy approach requires no source-code modification

    • Takes advantage of exported APIs

      Other potential domains for this work:

    • Other Microsoft Office applications

    • Web browsers