Waterfall AntiPatterns San Francisco Web Performance Group June 6, 2013 Rick Viscomi Performance Engineer
Jun 24, 2015
Waterfall AntiPatterns
San Francisco Web Performance Group
June 6, 2013
Rick ViscomiPerformance Engineer
About Me
● Web Developer○ YouTube○ Google
● Performance Engineer○ Food Network○ Travel Channel○ HGTV
● Open source developer○ trunk8 ○ red dwarf
jrvis.com
Web Performance
Waterfall Slope
Waterfall AntiPatterns
Anatomy of a Request
● DNS Lookup● Initial Connection● SSL Negotiation● TTFB● Content Download
HTTP Responses: Redirects
● 301 Moved Permanently● 302 Found
HTTP Responses: Not Modified
● Conditional GET
● Cache static content with long TTL○ Cache-Control: max-age=31536000
Last-Modified: Thu, 06 Jun 2013 15:17:34 GMT
● Cache busting○ style_20130606.css
HTTP Responses: Errors
● 404 Not Found
Extra Credit: What happened here?
Canceled Requests
Internet Explorer only »
Navigation Timing
● domContentLoaded* (document.ready)● Start Render (first paint)● loadEvent* (onload)● Document Complete (loadEventStart)* Chrome and Firefox only
Navigation Timing
Navigation Timing
Navigation Timing
Request Serialization
● "stair step" pattern
● many requests
● few connections○ 2 - 6
● HTTP 2.0?
Request Serialization
Connection View
cssjavascriptimagesflash
Request Serialization
Connection View
cssjavascriptimagesflash
Closed Connections
● TCP overhead
● Enable Keep-Alive
≈
Network Silence
● bandwidth utilization low
● CPU utilization high○ why?
Demo
Summary
● waterfall slope● request components● HTTP responses
○ redirects○ conditional GETs○ errors
● page load events● request concurrency● network utilization
Thank You
Rick [email protected]@rick_viscomi
Hands-OnWeb Performance
Optimization Workshop
Coming Soon:
June 18, 2013Santa Clara, CA
Preview: Worst of WebPagetest
● 46 requests○ 5 successful
● 21 seconds to Start Render
● 30% gzip savings
www.aplia.com
Preview: Worst of WebPagetest
● 443 requests
● 8,000 DOM elements
● 1.6 MB of JavaScript
● 75 unique domains
coder143.com
Preview: Worst of WebPagetest
● 2 MB page weight
● 26 second load time
● 17 second repeat view
www.taboradelaide.edu.au/
Thank You
Rick [email protected]@rick_viscomi
Hands-OnWeb Performance
Optimization Workshop
Coming Soon:
June 18, 2013Santa Clara, CA