Speed is Essential for a Great Web Experience (Canvas Conf Version)

Speed is Essential for a Great Web Experience (Canvas Conf Version)
Speed is Essential for a Great Web Experience @andydavies #CanvasConf Sep 2012 http://www.flickr.com/photos/barkaway/342359810
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 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
Bing did some experiments +1s $/ - 2.8% +
Wallmart made some improvements -1s +2%
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% of visitors 24% waited over 10s 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 Analytics Relies on Navigation Timing API, can add extra timing calls to page
Measuring Real Users - LogNormal
Measuring Real Users - Torbit Insight
Measuring Real Users - New Relic
webpagetest.org
Waterfall for bbc.co.uk/news
mobitest.akamai.com
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.uk debenhams.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 bottleneck 2.0 1.5 1.0 0.5 0s 5s 10s news.bbc.co.uk tested via webpagetest.org throttled at 1.5Mbps (bursts over 1.5Mbps are artefact of testing)
Minimum round trips to download a file (TCP Segments) 285kB 214kB 143kB 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
Going Faster… http://www.flickr.com/photos/mikebaird/2464769129/
Get the <head> straight <!doctype html> <html> <head> CSS before JS <meta charset="utf-8"> Ideally one file* <title>This is my title<title> <link rel="stylesheet" href="styles.css" type="text/css" /> <script src="script.js"></script> . . Only JS needed . during page load </head> * Bryan and Stephanie Rieger’s major and minor breakpoint approach requires multiple CSS files
Load remaining Javascript late as possible . . . <script src="restofscript.js"></script> </body> </html> One file or many? (Depends on size) Could you defer some JS until after onload?
Squash text based content - gzip / minify http://www.flickr.com/photos/evdg/298415813
Images are 64% of an ‘average’ web page http://www.flickr.com/photos/zaprittsky/4520788183/
Bitmapped Images JPEG PNG GIF Optimise, Optimise, Optimise! (jpegmini, pngmini, Smush.it, ImageOptim, Gifsicle etc.)
New Devices, New Challenges... 2 x Resolution = 4 x Pixels! http://www.flickr.com/photos/roopaw/6985954465
Some Alternatives CSS SVG Fonts Watch SVG - may not always be smaller than bitmap!
Re-use TCP Connections via HTTP Keep-Alive Orange segments are TCP connections being (re-) opened
news.bbcimg.co.uk static.bbc.co.uk Increase number of parallel downloads
Sometimes... The Waterfall of Doom! 2 seconds! (nearly)
Reduce number of HTTP requests
Cache resources that don’t change ‘often’ forever (use versions to replace) http://www.flickr.com/photos/sterlingely/64228609
Redirects - necessary but waste time… Why 2 redirects? Expensive over mobile networks due to latency
The Perils of Third Party Javascript... “Virgin Media Broadband ISP Users Affected by Website Routing Woes” ISP Review, May 26, 2012 cg-global.maxymiser.com unreachable
Impact on The Telegraph… Same issue affected many other sites http://bit.ly/Ncy7Rd
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> async attribute may be option but not supported by IE & Opera
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.com http://www.slideshare.net/andydavies http://www.flickr.com/photos/auntiep/5024494612
Credits All photographs copyright original owners on flickr.com Following pictograms courtesy of The Noun Project

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Speed is Essential for a Great Web Experience (Canvas Conf Version)