This document summarizes a talk on improving website performance. It discusses that the average load time of a web page is 4.9 seconds according to Google, and load times over 500 ms can result in a 20% drop in traffic. It emphasizes that 80-90% of end user response time is spent processing items on the front end like JavaScript and CSS. It provides tips for speeding up pages such as making fewer HTTP requests, using a content delivery network, adding expiration headers, gzipping components, placing stylesheets in the head and scripts at the bottom, avoiding CSS expressions, making JS and CSS external, reducing DNS lookups, minifying JavaScript, and more. It also lists tools that can help with analysis and optimization like

1. Mike Bailey
Melbourne Ruby Users Group
July, 2010

2. Go Faster, Webmaster!

3. Talks by techies from:
Google, Yahoo, Microsoft, Amazon, Twitter,
Facebook, Firefox, Firebug, Chrome, Internet
Explorer and more!
1200 attendees (sold out)
Mostly technical audience

4. The Need for Speed

5. The Need for Speed
"Average load time of a web page is 4.9 seconds"
- Urs Hölzle, Google

6. The Google Analytics exit rate for different page load times collected from Wikia data. Measured over 29 million pageviews

7. The Need for Speed
"Average load time of a web page is 4.9 seconds"
- Urs Hölzle, Google

8. The Need for Speed
"Average load time of a web page is 4.9 seconds"
- Urs Hölzle, Google
"The goal should be around 100 ms,
the time it takes for a reader to turn the page in a book"
- http://oreil.ly/bvYNk3

9. The Need for Speed
Google: +500 ms -20% traffic*
Amazon: +100 ms -1% sales*
* http://bit.ly/9iRqAu

10. We monitor backend performance

11. but what about the front end?

12. the importance of frontend
performance
9% 91%
17 83%
%
iGoogle, primed cache
iGoogle, empty cache
Steve Souders http://bit.ly/Zxh4m

13. time spent on the frontend
Empty Cache Primed Cache
www.aol.com 97% 97%
www.ebay.com 95% 81%
www.facebook.com 95% 81%
www.google.com/search 47% 0%
search.live.com/results 67% 0%
www.msn.com 98% 94%
www.myspace.com 98% 98%
en.wikipedia.org/wiki 94% 91%
www.yahoo.com 97% 96%
www.youtube.com 98% 97%
Steve Souders http://bit.ly/Zxh4m April 2008

14. The Performance Golden Rule
80-90% of the end-user response time is
spent on the frontend. Start there.
greater potential for improvement
simpler
proven to work
Steve Souders http://bit.ly/Zxh4m

15. To Measure is to Know

16. To Measure is to Know
Firefox - Firebug -> Net Window

17. To Measure is to Know
Firefox - Firebug -> Net Window
Chrome, Safari -> Web Inspector

18. To Measure is to Know
Firefox - Firebug -> Net Window
Chrome, Safari -> Web Inspector
IE -> HTTPWatch ($395-$44,395)

19. To Measure is to Know

20. To Measure is to Know
webpagetest.org

22. To Measure is to Know
webpagetest.org

23. To Measure is to Know
webpagetest.org
Webmaster Tools -> Labs -> Site Performance

25. To Measure is to Know
webpagetest.org
Webmaster Tools -> Labs -> Site Performance
showslow.com

27. Commercial Monitoring Services
gomez.com
keynote.com
webmetrics.com

28. How do we speed up our pages?

29. How do we speed up our pages?

30. How do we speed up our pages?

31. 1. MAKE FEWER HTTP REQUESTS
2. USE A CDN
3. ADD AN EXPIRES HEADER
4. GZIP COMPONENTS
5. PUT STYLESHEETS AT THE TOP
6. PUT SCRIPTS AT THE BOTTOM
7. AVOID CSS EXPRESSIONS
14 RULES
8. MAKE JS AND CSS EXTERNAL
9. REDUCE DNS LOOKUPS
10. MINIFY JS
11. AVOID REDIRECTS
12. REMOVE DUPLICATE SCRIPTS
13. CONFIGURE ETAGS
14. MAKE AJAX CACHEABLE

32. Analysis Tools

33. Analysis Tools
YSlow

34. Analysis Tools
YSlow
Page Speed

35. 14 Rule Redux
Make Fewer Requests
- combine javascripts, stylesheets
- use css sprites
- reduce DNS lookups
- avoid redirects
- enable proxy and browser caching of assets
Make Smaller Requests
- gzip components
- optimize images
- minify javascript

36. Tools to Help
http://spriteme.org/
http://smush.it/
http://stevesouders.com/cuzillion/

37. The Problem(s) with TCP

38. The Problem(s) with TCP
RFC 2581 TCP Congestion Control

39. John Rauser http://oreil.ly/dkvpgM

40. John Rauser http://oreil.ly/dkvpgM

41. The Problem(s) with TCP
RFC 2581 TCP Congestion Control

42. The Problem(s) with TCP
RFC 2581 TCP Congestion Control
RFC 813 Delayed ACK

43. John Rauser http://oreil.ly/dkvpgM

44. John Rauser http://oreil.ly/dkvpgM

45. John Rauser http://oreil.ly/dkvpgM

46. Real World Data
http://mike.bailey.net.au/blog?p=38

47. The Problem(s) with TCP
RFC 2581 TCP Congestion Control
RFC 813 Delayed ACK

48. The Problem(s) with TCP
RFC 2581 TCP Congestion Control
RFC 813 Delayed ACK
Google have proposed improvements

49. Quick wins

50. Quick wins
Google AJAX Libraries API

51. Quick wins
Google AJAX Libraries API
GA Async Tracking Code

52. Want to learn more?
Videos from Velocity 2010 http://bit.ly/bL0Msz
Read Steve Souder's books,
"High Performance Web Sites" & "Even Faster Web Sites"