Investigating the Impacts of Web Servers on Web

Application Energy Usage

Computer and Information Sciences University of Delaware

Irene L. Manotas G. Cagri Sahin

James Clause Lori Pollock

Kristina Winbladh

Which Web Server Should I Use?

Empirically Investigate

•  RQ1—Feasibility: Does the choice of web

server impact the energy consumption of a web application?

•  RQ2—Consistency: Are the web servers

consistent in their impact?

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Experimental Setup

web browser

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workloads

web server

web application

LEAP energy monitor

Integra+on  Tests  

Automa+c  Tes+ng  

user inputs

3  

WEBRick

4  

% Difference in energy consumption from the mean

Web Servers Feature Mongrel Puma Thin WEBrick

Calendar 10.10 -6.10 -8.50 2.30 Context Edit -1.40 -2.10 -0.10 3.40 Preferences -4.00 8.70 -4.00 -1.80 Review -1.10 -6.30 -1.30 7.70 Search 1.80 4.10 5.90 -0.60 Show Statistics 2.70 6.10 -13.90 2.90 Toggle Context -3.00 4.70 7.20 -10.70

Total 1.70 0.10 -3.60 1.70

§  A given web server is not always the best under all features.

§  The web server does make a difference §  Energy consumption variability differs across features.

4   4  This work is supported in part by National Science Foundation Grant No. 1216488 and an award from the University of Delaware Research Foundation

Results: Feasibility and Consistency

•  Correlating energy measurements with design decisions/implementations in a non-tedious manner

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Issues We Face

Questions for Discussion •  How are others monitoring and mapping energy usage

to program units? •  How many repeated runs do others perform to take

measurements to account for variations?