Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Measuring Web Performance

Measuring Web Performance

Today, a web page can be delivered to desktop computers, televisions, or handheld devices like tablets or phones. While a technique like responsive design helps ensure that our web sites look good across that spectrum of devices we may forget that we need to make sure that our web sites also perform well across that same spectrum. More and more of our users are shifting their Internet usage to these more varied platforms and connection speeds with some moving entirely to mobile Internet.

In this session we’ll look at the tools that can help you understand, measure and improve the web performance of your web sites and applications. The talk will also discuss how new server-side techniques might help us optimize our front-end performance. Finally, since the best way to test is to have devices in your hand, we’ll discuss some tips for getting your hands on them cheaply.

This presentation builds upon Dave’s “Optimization for Mobile” chapter in Smashing Magazine’s “The Mobile Book.”

This talk was given at the Responsive Web Design Summit hosted by Environments for Humans.

Dave Olsen

April 16, 2013

More Decks by Dave Olsen

Other Decks in Technology


  1. What I’ll Talk About • Quick Intro About Why We

    Should Care About Web Perf • Tools for Measuring Web Performance • Setting Up a Device Lab • Responsive Design + Server- side Solutions
  2. The way in which CSS media queries have been promoted

    for mobile hides tough problems and gives developers a false promise of a simple solution for designing for small screens. Source: Jason Grigsby on Speakerdeck “ ” - Jason Grigsby @grigs
  3. The average weight of a web page today. Source: HTTP

    Archive Images JavaScript Flash HTML CSS Other 77% 1.3 MB
  4. RWD sites whose small screen design weighs the same as

    the large screen design. Source: Podjarny 72%
  5. Users expect your mobile site to load as quickly as

    your desktop site. 71% Source: Gomez
  6. Bounce Rate Conversion Rate Cart Size Page Views 200ms -

    - - -1.2% 500ms -4.7% -1.9% - -5.7% 1000ms -8.3% -3.5% -2.1% -9.4% CASE STUDY: MOBILE PERFORMANCE EFFECT ON BUSINESS Source: Web Performance Today
  7. Over Downloading Download & Hide Download & Shrink Download &

    Ignore PRIMARY PERFORMANCE ISSUES FOR RWD Poor Networks High Latency Variable Bandwidth Packet Loss
  8. MOBILE OPTIMIZATION FOCUS 1. Reduce requests 2. Reduce asset size

    3. Speed-up page render http://flic.kr/p/4zzKee
  9. Best request is no request. Worst request is one that

    blocks the parser. Source: Ilya Grigorik “ ” - Ilya Grigorik @ilyagrigorik
  10. Browser cache The simplest way to reduce requests is to

    make sure the browser doesn’t need to make them. Make sure assets are bring cached on the browser. Concatenate JS & CSS Combine similar files together in one or multiple larger files to reduce requests. May harm performance too. Lazy load content Don’t make requests until necessary. Filament Group’s AJAX Include Pattern or lazyBlock. data: URI For small images & fonts try embedding them in your CSS file by using the data: URI. Conditional loading Use a resource loader like Modernizr.load to conditionally include JavaScript & CSS files. 1. REDUCE REQUESTS
  11. HTML & CSS compression Use mod_deflate to make sure text-based

    assets are compressed for transfer. Image compression Use a service like kraken.io to optimize images. Also use CSS sprites as appropriate. Try to avoid images When possible think about avoiding images. Implement with CSS or Canvas. Or use SVG or Progressive JPEGs. Minification Use a minifying service to make sure text-based assets are as small as possible. If using PHP use Minify. MicroJS or, even better, Vanilla JS Avoid using bulky frameworks if you’re using them for simple tasks like selectors. Try microjs.com to find libraries that may be smaller & more suitable. JavaScript also blocks the rendering of the page. 2. REDUCE ASSET SIZE
  12. Avoid DOM reflows & repaints By using JS to modify

    the DOM you can cause unnecessary reflows & repaints of your browser. They slow down page render time as well as burn battery. Defer loading of JavaScript Use HTML5’s script defer & async attributes to delay downloading files. Can also insert script elements into the DOM using the onLoad event. Lazy load JavaScript Comment out JavaScript that isn’t required at page load. Uncomment & eval() when required. Touch beats onClick While not directly related to page render, by making sure your links use a Touch event rather than an onClick event user interactions will speed up by 300ms. Avoid SM widgets Try using simple links to services rather than utilizing the JavaScript widgets. They’re performance hogs. 3. SPEED-UP PAGE RENDER
  13. mod_pagespeed AUTOMATES A LOT http://developers.google.com/speed/pagespeed/mod add_head combine_css convert_jpeg_to_progressive convert_meta_tags extend_cache

    flatten_css_imports inline_css inline_import_to_link inline_javascript rewrite_css rewrite_images rewrite_javascript rewrite_style_attributes_with_url Default Filters
  14. CodeKit CODEKIT: WEB PERF IN YOUR WORKFLOW Optimize Images Combine

    & Minify Features http://incident57.com/codekit/
  15. eBay MobileKarma.com Cellphone store leftovers Open device labs GET YOUR

    HANDS ON REAL DEVICES http://flic.kr/p/7972f6
  16. Base on: WiFi-capable, Analytics Rank, OS, Screen Dimensions, & Cost

    Suggested focus: iPod Touch, mid-level Android, high-end Android, a tablet, Blackberry, Windows Phone 7 HOW TO DECIDE WHICH TO GET iPod Touch Samsung Fascinate + Google Nexus + $438 Example:
  17. RESS* can be a scalpel for your responsive designs. REsponsive

    Design + Server Side Components http://flic.kr/p/a4VsPv
  18. Responsive Web Design + Server Side Components (I have no

    idea what becomes of the W, D, or C)
  19. - Luke Wroblewski @lukew http://www.lukew.com/ff/entry.asp?1392 In a nutshell, RESS combines

    adaptive layouts with server side component (not full page) optimization. So a single set of page templates define an entire Web site for all devices but key components within that site have device-class specific implementations that are rendered server side. “ ”
  20. http://www.lukew.com/ff/entry.asp?1509 - Luke Wroblewski @lukew • If you want layout

    adjustments across devices. • And optimization at the component level to increase performance or tune user experience. • You trust server-side device detection with sensible defaults. “ ”
  21. • Requires server-side languages. • Server-side feature detection so it

    can be spoofed. • RESS isn’t a silver bullet. • Data needs to be separated from layout. CHALLENGES FOR RESS
  22. - Jon Arnes Sæterås @jonarnes http://mpulp.mobi/2011/05/next-steps-of-responsive-web-design/ It is not only

    the design of the web site and the layout of content that needs to be adapted or enhanced; the idea of being responsive, adaptive and enhancing, must be implemented in the whole value chain. “ ”