Building High Performance Web Applications .............................................................................................................. .............................................................................................................. 

Karthik Kastury Perf. Engineer @ PayPal India Engineer / Hacker / Blogger / Apple fanboi and evil minded. *Pun Intended* 24x7 Internet Geek | Unlucky in Cards ................................................................................................................................ ................................................................................................................................ Blog Twitter Email http://karthik.kastury.in/ [email protected] @KarthikDot Internet Addict for 12+ Years... 

‣ #17 Best Places to Work - India (2011) ‣ #6 in Technology Companies in India ‣ Most Innovative Company in the Finance Industry and amongst Top 50 Most Innovative Companies in the World. [1] Best Place to Work Survey - India [2] Forbes Most Innovative Companies 

Let’s Get Started... .............................................................................................................. .............................................................................................................. 

Building High Performance Web Applications .............................................................................................................. 

High Performance? .............................................................................................................. .............................................................................................................. 

Performance Engineering ‣Reduce HTTP Requests. ‣ Use Image Sprites. ‣ CSS at the top, JS at the Bottom. ‣ CSS & JS Minified and Concatenated. ‣ Use a CDN for Static Assets. .............................................................................................................. .............................................................................................................. 

BUT THAT AIN’T ENOUGH ! .............................................................................................................. .............................................................................................................. 

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Traditional Methods are no Longer Enough. ‣ Lazy Loading FTW! ‣ Prevent Frontend SPOF. ‣ Early Flush / Chunked Responses. ‣ Async Script Loading. ‣ Google SPDY. .............................................................................................................. 

http://blog.patrickmeenan.com/2011/10/testing-for- frontend-spof.html Frontend SPOF 

Lazy Loading ‣ Load Scripts on Demand. ‣ Progressive Rendering - Show Only the most important parts, and progressively enhance/decorate. ‣ Render Content above the fold ASAP; and then render below the fold. .............................................................................................................. 

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Real Perf. vs Perceived Perf. ‣ Progressively Show the Content. ‣ Flush Buffers Early ‣ Load the Static Assets while the backend generates response. ‣ Flush at Regular Intervals. .............................................................................................................. 

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Early Flush - PayPal Here 

Async JS Loading + Polyfills .............................................................................................................. yepnope({ test : Modernizr.geolocation, yep : 'normal.js', nope : ['polyfill.js', 'wrapper.js'] }); 

yepnope([{ load: 'http:/­/ajax.googleapis.com/ajax/libs/jquery/1.5.1/ jquery.min.js', complete: function () { if (!window.jQuery) { yepnope('local/jquery.min.js'); } } }, { load: 'jquery.plugin.js', complete: function () { jQuery(function () { jQuery('div').plugin(); }); } }]); Async JS Loading + Resource Fallbacks .............................................................................................................. 

yepnope({ load: 'preload!jquery.1.5.0.js', callback: function (url, result, key) { window.jQuery; // undefined (but it's cached!); } }); Async JS Loading + Resource Preloading .............................................................................................................. 

.............................................................................................................. Key Idea Download all Scripts in Parallel and Execute in Order. 

Early Flush + Async JS Loading - PayPal Here 

GOOGLE SPDY! .............................................................................................................. .............................................................................................................. 

Google SPDY vs Plain Ol’ HTTP ‣ Multiplexed Streams (Single TCP Connection) ‣ Request Prioritization ‣ Header Compression ‣ Server Push .............................................................................................................. 

Google SPDY vs Plain Ol’ HTTP .............................................................................................................. 0 25 50 75 100 Without SSL With SSL HTTP Google SPDY Normalized Data for Top 100 Sites 

RUM (Real User Monitoring) .............................................................................................................. .............................................................................................................. 

.............................................................................................................. Monitor in PRODUCTION .............................................................................................................. 

The Real Story! .............................................................................................................. 

Yahoo! Boomerang ‣ Doc Complete, Page Response, Page Processing, TTFB, DNS, Connect & more ‣ Cookie data (for parent domain) ‣ Location (geolookup on IP) ‣ Referrer ‣ User Agent ‣ Anything else you want to stuff into the beacon https://github.com/yahoo/boomerang .............................................................................................................. 

Why RUM? .............................................................................................................. ‣ Get Real World Data. ‣ Monitor Perf. across Geographies, Browser Types. ‣ Roll out Optimizations and see how they perform with real data. 

What to Capture? .............................................................................................................. ‣ Geo Split. ‣ 95 %ile, 90 %ile, 75 %ile and 50 %ile Load times. ‣ Browser Data. ‣ Connect times in the Wild. Readymade solutions for RUM 

Summary .............................................................................................................. Reduce HTTP Requests. Use a CDN for Static Assets. Lazy Loading FTW! Prevent Frontend SPOF. Early Flush / Chunked Responses. Async Script Loading. Google SPDY. 

REDUCE THE PAIN OF YOUR USERS 

LIVE ON THE EDGE .............................................................................................................. .............................................................................................................. 

I’m available to help ................................................................................................................................ ................................................................................................................................ Blog Twitter Email http://karthik.kastury.in/ [email protected] @KarthikDot Ask http://karthik.kastury.in/ask 

.............................................................................................................. .............................................................................................................. Q&A 

THE END .............................................................................................................. .............................................................................................................. Or the start of something new.