1. CS193H: High Performance Web Sites Lecture 4: Class Projects Steve Souders Google souders@cs.stanford.edu

2. Announcements Office hours start today: Mondays 4:15-6pm Contact me by end of tomorrow (Tues 10/7) if you still want HTTPWatch and missed the first invite Computer Forum Career Fair - 10/8 11am-4pm between Gates and Packard

3. Guest Lecturer Review

4. Joseph Smarr, Plaxo "Performance Challenges for the Open Web" Minimizing roundtrips – discovery, association, OpenID, OAuth; separate vs. bundled Caching – freshness vs. speed Pull vs. push – scalability issues 3 rd party content – proxied vs. clientside; iframe vs. inline; XFBML, Caja

5. Lindsey Simon, Google "Front End Kung Fu" When you have a CSS problem: 1.is it in or out of the flow? 2.is box block or inline display context? Style specificity (higher wins): tag: 1 point className: 10 points id: 100 points inline style: 1000 points

6. Bill Scott, Netflix "High Performance Web Pages – Real World Examples: Netflix Case Study" Established metrics first – "Round Trip Tracers" Captured – bandwidth, browser, OS Gzip, far future Expires, removing Etags – cut outbound traffic in half Issue: Apache compresses "204 – No Content" responses; Safari 3 chokes

7. Bill Scott, Netflix (cont'd) Surprises! Spriting star bars slower – inline events Preloading CSS bg images – don't! IE7 twice as slow as FF3 – remember when coding "the little stuff multiplied matters" takeaway: track your changes, estimate their impact, go back and confirm and investigate

8. The Ajax Experience smushit.com image optimization there's no such thing as a "smu" Yahoo! Exceptional Performance talk The 7 Habits for Exceptional Performance I released Episodes and Hammerhead http://stevesouders.com/episodes/ http://stevesouders.com/hammerhead

9. Class Projects Web 100 Performance Profile Improving a Top 100 Web Site

10. Homework Download your class project web site and uploading to your Stanford directory Read HPWS, Chapter 1: Make Fewer HTTP Requests (if you haven't already)

11. Questions