Slides - UM Personal World Wide Web Server

Report
Anatomizing Application Performance
Differences on Smartphones
Junxian Huang, Qiang Xu, Birjodh Tiwana, Z. Morley Mao
University of Michigan
Ming Zhang, Victor Bahl
Microsoft Research
University of Michigan
Electrical Engineering and Computer Science
Smartphones are popular

Various smartphone platforms

Many applications

High speed network access


3G (UMTS & EVDO)
4G (LTE)
University of Michigan
Electrical Engineering and Computer Science
1
Understanding application performance is important
AT&T
T-Mobile
Verizon
University of Michigan
Electrical Engineering and Computer Science
2
Design tradeoff in smartphone measurement

User coverage vs. collected information
Liu, MobiCom 2008
Zhong, HotMetrics 2010
More info
Fewer users
Our study
Speedtest.net
FCC’s broadband test
Collected
information
Less info
More
users
User coverage
Willkomm, DySPAN 2008
University of Michigan
Electrical Engineering and Computer Science
3
Our contributions

3GTest



Widely deployed
Provide new insights into cellular network performance
A systematic methodology to understand application
performance




Isolate individual factors
Enable fair comparisons
Identify performance bottlenecks
Offer concrete recommendations for improvements
University of Michigan
Electrical Engineering and Computer Science
4
Outline

Cellular network performance study



Web performance analysis




3GTest design
3GTest results
Experimental methodology & setup
Web performance results
Streaming video & VoIP performance study
Conclusion
University of Michigan
Electrical Engineering and Computer Science
5
Key challenges of 3GTest

Adoptability





User privacy
Running time
Ease of use
Energy consumption
Data usefulness

Metrics relevant to network applications
University of Michigan
Electrical Engineering and Computer Science
6
How to make 3GTest easily adoptable?

Avoid personal identifiable information
http://www.eecs.umich.edu/3gtest
University of Michigan
Electrical Engineering and Computer Science
7
What information is most relevant for 3GTest?
example.com?
Get
index.html
192.0.32.10
<html></html>
Smartphone
Local DNS
server
Ping to
1st hop
University of Michigan
Electrical Engineering and Computer Science
End-end
ping
8
Web server
Representativeness of 3GTest data
66K+ users 148K+ runs 84 carriers 147 countries over 10 months
University of Michigan
Electrical Engineering and Computer Science
9
Throughput comparison
TMobile:600
kbps
CDF
AT&T
1Mbps
University of Michigan
Electrical Engineering and Computer Science
10
RTT comparison
T-Mobile
450ms
CDF
AT&T
350ms
University of Michigan
Electrical Engineering and Computer Science
11
Retransmission rate comparison
AT&T
CDF
T-Mobile
University of Michigan
Electrical Engineering and Computer Science
12
Insights from 3GTest results

Local DNS server performance is good


Carrier network delay dominates end-to-end RTT


End-end ping close to ping to 1st hop
Time of day effect


200 ms comparable to ping to 1st hop
AT&T’s downlink throughput
Signal strength correlates with TCP performance
University of Michigan
Electrical Engineering and Computer Science
13
Smartphone web browsing is complicated
DNS lookup
1
Local DNS
server
Content customization
Client configuration
Server
configuration
Server
processing
delay
HTML rendering &
JavaScript execution
5
3
Network condition
Smartphone
2
4
TCP handshake
TCP data transfer
University of Michigan
Electrical Engineering and Computer Science
14
Web server
Key challenges of web performance analysis

Multiple factors have impact





Network condition
Client settings
Server configurations
Content differences
Lack of low-level information and access



No visibility into link layer
Difficult to instrument client OS and application
No access to public web servers
University of Michigan
Electrical Engineering and Computer Science
15
How to isolate impact of individual factor?

Vary one factor at a time

Network condition


Client settings

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Control TCP concurrency
Server configurations


Simulate cellular network with WiFi
Change compression mode and server parallelism
Content difference

Host static website snapshots locally
University of Michigan
Electrical Engineering and Computer Science
16
How to identify performance bottlenecks?

TCP flow analysis technique to break down page load time




DNS lookup time
TCP handshake time
TCP idle time
TCP transfer time
index.html
logo.png
Time
University of Michigan
Electrical Engineering and Computer Science
17
Controlled experiment setup

Platform

Web browsing

Other applications
University of Michigan
Electrical Engineering and Computer Science
18
Simple website page load time break down
TCP transfer time
TCP idle time
http://m.ebay.com
University of Michigan
Electrical Engineering and Computer Science
19
Content-rich website page load time break down
TCP transfer time
TCP idle time
http://mapquest.com
University of Michigan
Electrical Engineering and Computer Science
20
JavaScript execution comparison
80X (CPU
PC <10X)
University of Michigan
Electrical Engineering and Computer Science
21
Lessons from application performance study

Performance bottlenecks of web browsing





Higher concurrency significantly improves performance
Compression is usually helpful
Content customization is beneficial




Client execution
Data download
Data URL scheme
Minification
Minimal redirections
Video & VoIP

Platform specific application behaviors
University of Michigan
Electrical Engineering and Computer Science
22
Conclusion

3GTest for measuring cellular network performance



Deployed widely
Gain insights into cellular network performance
A systematic methodology to understand application
performance



Isolate impact of individual factor
Identify performance bottlenecks
Offer recommendations on performance improvement
University of Michigan
Electrical Engineering and Computer Science
23
Visit 3GTest website
http://www.eecs.umich.edu/3gtest
iPhone
University of Michigan
Electrical Engineering and Computer Science
Android
24
Windows Mobile

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