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Peter Hedenskog
September 04, 2014
Technology
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How to make your boss speed-curious and other webperf tricks - coldfront2014
My presentation from ColdFront2014:
http://coldfrontconf.com/
Peter Hedenskog
September 04, 2014
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Transcript
How to make your boss speed-curious and other #webperf tricks
Peter Hedenskog
None
None
The Performance Golden Rule!
80-90% of the end-user response time is spent on the
frontend.
front end dev
front end dev
front end dev
front end dev
front end dev
front end dev
With great power …
comes great responsibility!
2
How to be really fast
The boss
World fastest web page
None
Start render: 0,2 s Visually Complete: 0,2 s
What can we learn?
What CDN are you using?
We know the Golden rule!
The rendering path
1. Download HTML
2. If CSS files then download
3. If JS files then download
4. DOM + CSSOM = render tree
5. Paint
Optimize the rendering path
“I like thinking big.” Donald Trump
“Think small” Peter Hedenskog
What?
super computers
super fast internet
remember
mobile phones
data
the city
magic number
14:ish kb
High Performance Browser Networking - Ilya Grigorik Paul Irish
focus
above the fold
“Think small” Peter Hedenskog
Overall
minimize
combine
avoid requests
no requests
HTML
DOM node depth
CSS
inline
<head> ... <style> body { background: #fff; } ... </style>
</head> <body>
https://github.com/filamentgroup/loadCSS
None
NEVER
Avoid reflow and repaint
None
Javascript
JAVASCRIPT CAN BE EVIL
JAVASCRIPT IS EVIL* *inside your rendering path
Synchronously loaded Javascript blocks the rendering path!
Example of non working
NEVER
use async <script src=“/js/calculate.js” async></script> https://www.igvita.com/2014/05/20/script-injected-async-scripts-considered-harmful/
measure above the fold
User Timing API
window.performance. mark(‘logoLoaded’);
window.performance. measure(‘logoTiming’, ‘navigationStart’, ‘logoLoaded’);
var items = window.performance .getEntriesByType(' measure');
None
There’s a polyfill for that!
https://gist.github.com/pmeenan/5902672
Demo
front end dev
The boss
2 kinds
money
http:// www.peterhedenskog.com/ blog/2014/09/more-speed- more-money/
end user Be kind to your users! Mother Theresa
< 0.1 second - instant < 1.0 second - flow
=>10 seconds - lost ! Robert B. Miller - Response Time in Man-Computer Conversational Transactions (1968) The brain
Visualize
Your boss understands red, yellow and green
1200 ms
red 1200 ms
yellow 1200 ms
green 1200 ms
None
x
we are 12% slower than …
None
summary
front end dev
None
small
None
•Peter in Denmark - Lars Von Trier •Donald Trump -
Gage Skidmore •Super computer - Zdjęcia Arkadiusz Sikorski •Monkey with iphone - Marsel Van Oosten •The house - Bert Kaufmann •Stop light peppers - Dennis S Hurd •What is this? - Jeff Carson •Corcovado jesus - Doug88888 •Developers - Austin Wordpress Camp •The evil king - HBO •Pippi Longstocking - Ingrid Vang Nyman •Montgomery Burns - Matt Groening •The dog - Emiliano •Paint over - franziska •Super heroes - Marvel •Vee - Netflix Image credits
Thank you! Peter Hedenskog
[email protected]
@soulislove