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Performance Implications of Mobile Design


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Choosing your mobile design paradigm is hard, and performance is an often overlooked parameter in this decision process. …

Choosing your mobile design paradigm is hard, and performance is an often overlooked parameter in this decision process.

This presentation discusses the top performance concerns for the top mobile design paradigms - Dedicated Sites (mdot) and Responsive Web Design (RWD).

Presented at Breaking Dev (bdconf) in April, 2012.

Published in: Technology, Design
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  • 1. Performance Implications of Mobile DesignGuy Podjarny@guypodguy@akamai.com Akamai Confidential
  • 2. Good Morning! Faster ForwardTM ©2012 Akamai
  • 3. Agenda• Performance Matters!• Focus on top Mobile Design Paradigms • A bit on Dedicates Sites (mdot) • A lot on Responsive Web Design• Review Performance each Paradigm • Dig into the top performance problem • Show what went wrong • Discuss how you can fix it• Share tools that can help • And how to use them• Summary Faster ForwardTM ©2012 Akamai
  • 4. Who Am I #1: Ex-CTO of (now Akamai) Faster ForwardTM ©2012 Akamai
  • 5. Who Am I #2: Blaze Mobitest• Mobile Web Performance Measurement • Free Online Service:• Now Open-Source! • For more details: Faster ForwardTM ©2012 Akamai
  • 6. Who Am I #3: Mobile Performance Researcher Faster ForwardTM ©2012 Akamai
  • 7. Some Terminology Faster ForwardTM ©2012 Akamai
  • 8. Dedicated Sites (mdot) URL/Website Per Device Profile Faster ForwardTM ©2012 Akamai
  • 9. Responsive Web Design One URL, Adapt to screen size Faster ForwardTM ©2012 Akamai
  • 10. Mobile First & Desktop First included in RWD Mobile First (Progressive Enhancement) Desktop First(Graceful Degradation) Faster ForwardTM ©2012 Akamai
  • 11. Waterfall Charts Resource Doc Complete, Waterfall (Request/Response) (a.k.a. onload, Chart Start Render Load Time) Faster ForwardTM ©2012 Akamai
  • 12. Please don‟t hate me…• I use real world examples • Possibly written by you…• Constructive feedback != bashing • These are common mistakes • We should learn from them• I tried to spread the blame • Plenty of sites to choose from…• If you fix it, let me know! • I‟ll spread the word Faster ForwardTM ©2012 Akamai
  • 13. Performance Matters! Akamai Confidential
  • 14. Users Expect Fast Sites Source: Akamai Faster ForwardTM ©2012 Akamai
  • 15. Users Abandon Slow Sites Page Abandonment vs. Load Time Source: KISS Metrics Faster ForwardTM ©2012 Akamai
  • 16. Fast Sites Help Bottom Lines Shopzilla: 5 sec load time improvement Source: Shopzilla Faster ForwardTM ©2012 Akamai
  • 17. Mobile Users Expect Equal Speeds Source: Gomez Faster ForwardTM ©2012 Akamai
  • 18. Dedicated Sites (mdot) Akamai Confidential
  • 19. Mdot Dedicated Sites don‟t create new performance problems Still have old problems, but that‟s not related to mobile design Faster ForwardTM ©2012 Akamai
  • 20. Small Mobile Site, Small Waterfall , iPhone 4, iOS 5.0 Faster ForwardTM ©2012 Akamai
  • 21. Big Desktop/Tablet Site, Big Waterfall Chart iPad 2 iOS 5 Faster ForwardTM ©2012 Akamai
  • 22. Dedicated Sites Top Performance Problem Redirects m. www. Faster ForwardTM ©2012 Akamai
  • 23. Redirects are expensive!www.espn.com2 redirects, 1.3 seconds lost Faster ForwardTM ©2012 Akamai
  • 24. Late Redirect using scripts are even slowerwww.disney.com2 redirects + JS Redirect, 3 seconds lost Faster ForwardTM ©2012 Akamai
  • 25. Could get nastywww.garmin.com3 redirects + JS Redirect, 3.6 seconds lost Faster ForwardTM ©2012 Akamai
  • 26. Redirects – What To Do?• Minimize Redirects • Merge redirect chains• Use HTTP Redirects, not JS redirects • Keep the client-side detection as backup • Detect most devices server-side• Cache HTTP Redirects on the CDN • Makes the extra round trip shorter• Use HTTP 301 Redirect, with a future Expiry • 302/303/307 redirects are not cached by the browser • Good test page (by @souders): Faster ForwardTM ©2012 Akamai
  • 27. Responsive Web Design Akamai Confidential
  • 28. Responsive Web Design Responsive Web Design Top Performance Problem: Over-Downloading Faster ForwardTM ©2012 Akamai
  • 29. Test – Compare Sites on Different Resolutions• Data: • 347 Sites from• Testing Methodology: • Use • Use Chrome browser • Resize window before each measurement •Resolutions: 320x480, 480x960, 1024x768, 1600x1200 • Saw similar results with iPhone vs. iPad tests• Collect Results • Excel & Pivot Tables(Automated version of Jason Grigsby‟s test last year) © Faster ForwardTM ©2012 Akamai
  • 30. Responsive Sites Load Times & Size, by Resolution Load Time* by Resolution (ms)4,0003,5003,0002,5002,0001,5001,000 500 0 Page Size by Resolution (KB) 1,200 1,000 800 600 400 200 0* Over Cable Speed(5 Mbps down, 1 Mbps up, 28ms RTT) Faster ForwardTM ©2012 Akamai
  • 31. Small Screen = Less Visible Content != Less Bytes 320x48 1600x120 0 0 Faster ForwardTM ©2012 Akamai
  • 32. Some depressing stats…Page Size 10 Got Lucky 320x480 A Bit Smaller (BG 11% Image, Fonts, vs …)1600x1200 Much Smaller 3% Same Size 86% 1 Responsive ImagesA bit smaller = 50%-90% the sizeMuch smaller = <50% the size Faster ForwardTM ©2012 Akamai
  • 33. Big Site, Big Waterfall 1600x120 0 Faster ForwardTM ©2012 Akamai
  • 34. Small Site, Big Waterfall 320x480 Faster ForwardTM ©2012 Akamai
  • 35. Download and HideRich Side-bar,holds ads and more Display set to none Faster ForwardTM ©2012 Akamai
  • 36. Hidden content is still downloaded Display set to none, resources are still downloaded! Faster ForwardTM ©2012 Akamai
  • 37. Download and Shrink Smaller Screen, Same Size Image Faster ForwardTM ©2012 Akamai
  • 38. Media queries don‟t prevent CSS downloads Separate CSS per media basic.css mobile.css 320x480“Right” CSS loaded“Wrong” CSS loaded- May be used by JavaScript- Possibly delayed till just before onload desktop.css Faster ForwardTM ©2012 Akamai
  • 39. Excess DOM1402 elements 1398 elements3485 nodes 3491 nodes Simplicity not reflected in DOM 1600x1200 320x480 Faster ForwardTM ©2012 Akamai
  • 40. RWD Woes• Download and Hide• Download and Shrink• Extra CSS Download• Excess DOM Faster ForwardTM ©2012 Akamai
  • 41. What Can We Do About It?! Akamai Confidential
  • 42. Images accounts for most mobile pages sizeStats from Faster ForwardTM ©2012 Akamai
  • 43. Responsive Images 128px, 240px, 6.8 KB 2.9 KB 320px, 10.6 KB 480px, 21.3 KBSite:lonelyplanet.comDevice:iPhone 4Before: Full Res, 50.1 KB867 KBAfter:570 KB Faster ForwardTM ©2012 Akamai
  • 44. Responding Up (or badly?) ipad_hero.jpg 113 KB Served to Desktop ipad_hero_2x.jpg 360 KBServed to New iPad Faster ForwardTM ©2012 Akamai
  • 45. Low Hanging Fruit: Responsive Images• Responsive Images = Serve lower res images to smaller screens • Optionally load full res image in the background• Lots of great resources on how to do it • Cloud Four blog - Education • Src – Helper Tool• Responsive images apply to CSS too! • Especially to background images • And stop with the huge images! Faster ForwardTM ©2012 Akamai
  • 46. Build Mobile First• Don‟t just design Mobile First – Code a Mobile-only site • Build only for the lowest resolution you care about • Adapt to similar screen sizes: No layout shifts, no big resolution jumps • Performance should compare to mdot sites• Once implemented – Enhance via JavaScript • Grow DOM only on screens that need it.• Desktop clients with no JS support are a minority • Your mobile site should be good enough for those • Don‟t sacrifice the performance of 99% for the remaining 1% Faster ForwardTM ©2012 Akamai
  • 47. Enhancing via JavaScript – Tips & Tricks 1600px• Split your files by layout/resolution 480 • Duplicating content on the server is ok 320 px px • Duplicating download is not• Use Inline JavaScript to decide the layout • Then use external (cacheable) files to apply it• Put scripts that change design at the top • JavaScript blocks rendering • Will avoid FOUC – Flash Of Unstyled Content • Put all other scripts at the bottom var css = „small.css‟; if (window.innerWidth > 640) css = „large.css‟; else if (window.innerWidth >= 320) css = „medium.css‟; document.write(„<link type=“stylesheet” rel=“stylesheet” href=“‟+css+‟”/>‟); Faster ForwardTM ©2012 Akamai
  • 48. Don‟t forget the “regular” concerns• Reduce HTTP requests • Consolidate Files • Inline tiny files• Reduce bytes • Minify CSS/JS • Use Lossless Compression for Images• Load visible content first • Defer everything else • Or Load it on demand• Avoid CSS Imports•… Faster ForwardTM ©2012 Akamai
  • 49. Measure! • Mobitest • Online service: • Install local open-source version (details) • Google‟s Pcapperf • Convert network capture to waterfall charts • • Stoyan Stefanov‟s “icy” • HTTP insight into iOS HTTP requests • • @firt‟s iWebInspector • Remote debugger for iOS simulator • Faster ForwardTM ©2012 Akamai
  • 50. Testing different screen dimensions• Run webpagetest script with resizing • Use Chrome as agent (not supported on other browsers) • Sample script (tab delimited): setviewportsize 320 480 navigate • Many other scripting options: webpagetest/scripting• Figure out the viewport dimensions you want to simulate • Faster ForwardTM ©2012 Akamai
  • 51. Summary Akamai Confidential
  • 52. Summary• Choosing your mobile design is HARD• There are many factors to consider• Design Decision have Performance Implications• Mdot Primary Concern: Redirects• RWD Primary Concern: Over-Downloading• Either design paradigm can be made fast• Performance should be built in – not bolted on• Measure!• Make perf testing a part the core functionality test Faster ForwardTM ©2012 Akamai
  • 53. Questions? Performance Implications of Mobile DesignGuy Podjarny@guypodguy@akamai.com Akamai Confidential