Speed is Essential for a Great Web Experience

Speed is Essential for aGreat Web Experience@andydaviesPort 80 (#p80N)May 2012 http://www.ﬂickr.com/photos/44442915@N00/5214810596

But sometimes other concerns take priority... http://www.ﬂickr.com/photos/randomidea/247994072

“Are we there yet?” http://www.ﬂickr.com/photos/sharynmorrow/643126727

Our perception of response time Instant Seamless Yawn!100ms 1s 10s Response Time in Man-computer Conversational Transactions Robert B. Miller, 1968

Our perception of response time Instant Seamless Yawn!100ms 1s 10s 3s - Recommended 7s - Fortune 500 Load Time Average (2010) Response Time in Man-computer Conversational Transactions Robert B. Miller, 1968

“50% more concentration when using badly performing web sites” Foviance http://www.ﬂickr.com/photos/yourdon/3366991042

Effect of delay on abandonment rate... Abandonment rate over 200+ sites / 177+ million page views over 2 weeks - http://www.measureworks.nl / Gomez

Google conducted an experiment +400ms -0.6%

Bing did some experiments too +1s $/ - 2.8% +

Shopzilla cut page load time by 5 seconds! +12% +25% -50% $$$ http://velocityconf.com/velocity2009/public/schedule/detail/7709

Measuring page load time...

Measure Real Users’ Experience 27% 24%Visitors (%) 13% 8% 8% 6% 6% 3% 3% 2% 1% 1 2 3 4 5 6 7 8 9 10 > 10 Load Time (s)

Measuring Real Users - Google AnalyticsRelies on Navigation Timing API, can add extra timing calls to page

Measuring Real Users - Torbit Insight

Measuring Real Users - Torbit Insight (Check out at Log Normal too)

Measuring Real Users - New Relic

webpagetest.org

Waterfall for bbc.co.uk/news

www.blaze.io/mobile

Bigger, Faster Servers? http://www.ﬂickr.com/photos/br1dotcom/4297736794

80% plus of page load time is on front-end Backend news.bbc.co.uk Frontend ebay.co.ukdebenhams.co.uk direct.gov.uk amazon.co.uk mumsnet.com guardian.co.uk 0 1.25 2.5 3.75 5 Measured on residential ADSL line using Chrome 19

Fix slow server responses ﬁrst 4 seconds!

Bandwidth (often) isn’t the bottleneck2.01.51.00.5 0s 5s 10s news.bbc.co.uk tested via webpagetest.org throttled at 1.5Mbps (bursts over 1.5Mbps are artifact of testing)

Minimum round trips to download a ﬁle (TCP Segments)285kB214kB143kB 71kB Size 1 2 3 4 5 6 7 8 9 10 11 Round Trips TCP and the Lower Bound of Web Performance John Rauser

Speeding Things Up - The Basics CSS at top Compress Consilidate Minify Reduce Requests Cache Forever JS at bottom

Proportion of URLs that can be compressed ☺ ☹ http://zoompf.com/blog/2012/05/http-compression-use-by-alexa-top-1000

What’s the web made of? Images Scripts Stylesheets HTML Flash Other Composition of ‘average’ web page via httparchive.org

Bitmapped Images JPEG PNG GIF Optimise, Optimise, Optimise! (jpegmini, pngmini, Smush.it, ImageOptim, Gifsicle etc.)

CSS Sprites + background-position: -408px 0; width: 128px; height: 128px; =

Data-URIs<img width="128" height="128"src="data:image/PNG;base64,iVBORw0KGgoAAAANSUhEUgAAAIAA ... =GAA39eV7u4AAAAAElFTkSuQ" /> Should be served with GZIP

New Devices, New Challenges... 2 x Resolution = 4 x Pixels! http://www.ﬂickr.com/photos/roopaw/6985954465

Look Ma, No Images!border-radius: 20px;background: linear-gradient(left, #f06, #ff0); Watch mobile performance. Remember vendor preﬁxes!

Vector Graphics FTW? SVG: 12 KB vs PNG: 86KB

What about icon / pictogram fonts? ★ ★ ☆ ☆ ♥ ♥ ☁ ☁ Heydings by Heydon Works “Bog Standard Font”

display:none - still downloads images “‪#p80n‬ you do get adverts on the smashingmag site on smaller viewports. They just hideously display:none; so you still down load them :-/” @sturobson ‬

Don’t forget about favicon.ico 1.4 seconds for favicon!

Don’t forget about favicon.ico 1.4 seconds for favicon! <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

Don’t block the browser... http://www.ﬂickr.com/photos/barteko/6128499314

news.bbcimg.co.uk static.bbc.co.ukBrowsers can download resources in parallel

But Sometimes... The Waterfall of Doom! 2 seconds! (nearly)

Social buttons break... http://bit.ly/yRjX63

Load Third Party scripts asynchronously <script type="text/javascript"> function() var js = document.createElement(script); js.async = true; js.src = myscript.js var e = document.getElementsByTagName(script)[0]; e.parentNode.insertBefore(js, first); })(); </script>

Argh... My brain hurts! http://www.ﬂickr.com/photos/corneveaux/3248566797

Don’t have to do it all by hand http://www.ﬂickr.com/photos/simeon_barkas/2557059247

Performance isn’t just for Christmas Measure Optimise Analyse

http://www.ﬂickr.com/photos/jurvetson/6212582593

@andydavies andy@asteno.comhttp://www.slideshare.net/andydavies http://www.ﬂickr.com/photos/auntiep/5024494612

CreditsAll photographs copyright original owners on ﬂickr.comFollowing pictograms courtesy of The Noun Project

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http://col.educa.khipu.net	58
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https://twitter.com	13
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http://confluence-test.ndlap3.seria.net	3
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Speed is Essential for a Great Web Experience

by Andy Davies on May 25, 2012

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