100ms 1s 10s
Response Time in Man-computer Conversational Transactions
Robert B. Miller, 1968
Instant
Seamless Yawn!
Our perception of response time
3s - Recommended
Load Time
6.5s - Alexa 2000
Fall 2012
Miller Response Time 1968
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Bing did some experiments
+1s - 2.8%
+1s
$/
Time to click +2s
Bing
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Walmart
Wallmart made some improvements
-1s +2%
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Shopzilla
http://velocityconf.com/velocity2009/public/schedule/detail/7709
$$$
+12% +25% -50%
From 6-9s down to 1.2s
Impact of latency
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Page Load Time (s)
Round Trip Time (ms)
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The front-end
really matters
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80% of time is front-end
news.bbc.co.uk
ebay.co.uk
debenhams.co.uk
direct.gov.uk
amazon.co.uk
mumsnet.com
guardian.co.uk
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Backend
Frontend
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Still got to fix the backend!
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327k (32%) bigger in one year
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Onload ≠ User perception
2.0s 88% rendered 5.2s window.onload
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So how do we
measure speed?
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Uptime monitoring (Pingdom)
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Synthetic testing
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Only the HTML request measured
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Real user monitoring (RUM)
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New Relic RUM
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APDEX
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GA site speed
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GA site speed
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GA site speed
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GA Site speed sample rate
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-XXXXX-XX']);
_gaq.push(['_setSiteSpeedSampleRate', 100]);
_gaq.push(['_trackPageview']);
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GA User timing
_gaq.push([‘_trackTiming’,
‘jQuery’,‘Load Library’, 20,
‘Google CDN’,50]);
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GA User timing
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GA User timing
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Performance benchmarking
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How do I make
it faster?
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Google PageSpeed Insight
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WebPagetest
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stevesouders.com/hpws/
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browserdiet.com
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How do I make
it faster across
all those devices?
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Responsive Design
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1. Build mobile first responsive designs
2. Keep CSS background images in scoped media
queries
3. Conditionally load JavaScript and even HTML
fragments based on screen size and capabilities
4. Implement a responsive images solution
5. Handle retina images very carefully and err on the
side of performance
Jason Grigsby