Slides from the workshop I conducted on "Client-side Performance Testing". Abstract of the workshop: In this workshop, we will see the different dimensions of Performance Testing and Performance Engineering, and focus on Client-side Performance Testing. Before we get to doing some Client-side Performance Testing activities, we will first understand how to look at client-side performance, and putting that in the context of the product under test. We will see, using a case study, the impact of caching on performance, the good & the bad! We will then experiment with some tools like WebPageTest and Page Speed to understand how to measure client-side performance. Lastly - just understanding the performance of the product is not sufficient. We will look at how to automate the testing for this activity - using WebPageTest (private instance setup), and experiment with yslow - as a low-cost, programatic alternative to WebPageTest.

1. CLIENT-SIDE
PERFORMANCE
TESTING
Anand Bagmar
Test Practice Lead

2. @BagmarAnand
about.me/anand.bagmar
ABOUT ME

3. WHAT DO YOU EXPECT FROM THIS SESSION?

4. What is
Performance Testing?

5. What is
Performance Engineering?

6. TYPICAL ARCHITECTURE

7. Lets draw!

8. Caching!
In computing, a cache (/kæʃ/ KASH) is a component that stores
data so future requests for that data can be served faster; the data
stored in a cache might be the results of an earlier computation, or
the duplicates of data stored elsewhere.

9. Where can caching be done?

10. TYPICAL ARCHITECTURE
Improve user experienceReduce server load

11. WE WILL FOCUS ON
Improve user experienceReduce server load

12. Measuring Client-side
Performance

13. MEASURING CLIENT SIDE PERFORMANCE
Synthetic Monitoring (& Testing)
Ø WebPageTest.org
Ø SiteSpeed.io
Ø ShowSlow
Ø Google PageSpeed

14. MEASURING CLIENT SIDE PERFORMANCE
Real User Monitoring
Ø Akamai RUM
Ø Monitis RUM
Ø Google Analytics

15. WebPageTest.org

16. WEBPAGETEST – HOSTED SOLUTION
Advantages
Ø Free to use
Ø Global spread
Ø Caters to current web development practices /
approaches (responsive / lazy loading / etc.)

17. Lets Play!

18. IMPORTANT METRICS
What to
Measure?
WebPageTest
Metric
Explanation
First
reaction
Time to First
Byte (TTFB)
Time from the start of the initial navigation until the first
byte of the base page is received by the browser (after
following redirects).
Content
appears
Time to Start
Render
Time from the start of the initial navigation until the first
non-white content is painted to the browser display.
Page
processing
completed
DOM Content
Ready End
The point when the HTML parser has reached the end of
the document which means it has executed any blocking
scripts. The CSSOM may not be complete yet.
Full page
loaded
Doc Complete
Time
The onload event which fires when all of the scripts, css and
images defined in the HTML have finished loading
(including below-the-fold content).
Refer to WebPageTest documentation for more details:
• https://sites.google.com/a/webpagetest.org/docs/using-webpagetest/metrics
• https://sites.google.com/a/webpagetest.org/docs/advanced-features/raw-test-results

19. WEBPAGETEST – HOSTED SOLUTION
Disadvantages
Ø Need to get in the queue of currently executing tests
Ø Can run only against publically available URLs / pages
Ø Limited automation using REST APIs

20. WEBPAGETEST – PRIVATE INSTANCE
Advantages
Ø Free to use, Open-source
Ø Can run multiple scenarios in parallel (limited by number
of agents configured)
Ø Can run against public and private available URLs / pages
Ø Results available for as long as configured
Ø There is no limit on number of tests run per day

21. WEBPAGETEST – PRIVATE INSTANCE
Disadvantages
Ø Need to setup the WPT server and WPT agents in our own
infrastructure, or in AWS

22. WEBPAGETEST - AUTOMATION
Ø REST API calls
Ø Poll for results / implement call back
Ø Parse summary / detail CSV file to do assertions /
validations
Challenges
Ø Managing infrastructure
Ø Polling for results can be time consuming and error prone

23. YSlow

24. YSLOW
Advantages
Ø Simple to use (with phantomJS)
Ø Gives reasonably decent information
Ø Easy to hook with Continuous Integration (CI) Server

25. Lets Play!

26. YSLOW
Disadvantages
Ø OLD
Ø Does not consider lazy loading / responsive design

27. Google’s PageSpeed Score

28. Lets Play!

29. GOOGLE PAGE SPEED
Ø De facto standard
Ø Shows opportunities to increase page speed score
Ø Works only for public URLs / pages

30. RESOURCES
Ø www.webpagetest.org
Ø Page Speed
Ø PhantomJS – YSlow
Ø Sample automation –client-side-perf-tests

31. abagmar@gmail.com
Anand.Bagmar@thoughtworks.com
@BagmarAnand
about.me/anand.bagmar
THANK YOU