Faster mobile sites


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Faster mobile sites

  1. 1. Wednesday, March 21, 12
  2. 2. Mobile Faster Mobile Sites Presented by Matt FarinaWednesday, March 21, 12
  3. 3. Hi, My name is Matt.You might know me as mfer. @mattfarinaWednesday, March 21, 12
  4. 4. Download the slides..., March 21, 12
  5. 5., March 21, 12
  6. 6. Take Aways 1. Why front end performance is important. 2. Where to look for performance issues. 3. Resources, tools, and stuff you can use. 4. Some actions you can take on your site.Wednesday, March 21, 12
  7. 7. Before We Get Started Before we talk about the fun and new stuff there’s are some things commonly talked about you should look into: • CDN • Memcache • Varnish • Lots of other cool stuff • APCWednesday, March 21, 12
  8. 8. Why is Front End Performance Important?Wednesday, March 21, 12
  9. 9. The HTTP Archive measurement of where time spent generating a page happens for the top 50K sites. Front End Back End 13% 87%, March 21, 12
  10. 10. Front End Back End Front End Back End 15% 3% 85% 97% Desktop Mobile, March 21, 12
  11. 11. 85% of mobile users expect sites to load at least as fast as using a desktop or laptop computer., March 21, 12
  12. 12. 57% of online shoppers will wait three seconds or less before abandoning the site., March 21, 12
  13. 13. “Yahoo! reported that making pages just 400 milliseconds slower resulted in a traffic drop of up to 9%.” * Google, Amazon, and others have found similar results., March 21, 12
  14. 14. SEO Google takes performance into account in search engine rankings., March 21, 12
  15. 15. We aren’t just competing over user time and attention with other websites. We’re also competing against native apps.Wednesday, March 21, 12
  16. 16. Part 1: BandwidthWednesday, March 21, 12
  17. 17. 4G will solve our problems, right?, March 21, 12
  18. 18. According to ITU (UN agency for information and communications technology) in 2011 we only had 45% of 3g or better coverage worldwide., March 21, 12
  19. 19. “Research done at Google shows that an increase from 5Mbps to 10Mbps results in a disappointing 5% improvement in page load times. Or put slightly differently, a 10Mbps connection, on average uses only 16% of its capacity.”, March 21, 12
  20. 20. TCP connections aren’t great for small files (all your non-media assets are small files). This is due to TCP slow start., March 21, 12
  21. 21. If you pay for bandwidth and you can use less bandwidth to send the same functionality you have a savings at the same usage level.Wednesday, March 21, 12
  22. 22. Minify Production JavaScript • For example, minified drupal.js is 24% the size of the original. • UglifyJS - a great minifier • Speedy Module - minified core JS • Advanced CSS/JS Aggregation (D 6.x), March 21, 12
  23. 23. Quick Note On Legal Issues • JavaScript downloaded to the browser is a form of distribution. • The source (non-minified) must be linked to or publicly available. This could be a link in a comment. • Preserve copyright / attribution comments. Note: I’m not a lawyer and this is not legal advice.Wednesday, March 21, 12
  24. 24. Contrib Challenge: If a project in contrib is using un-minified JavaScript for production file a bug. Remember, patches welcome.Wednesday, March 21, 12
  25. 25. Original 41.3% Smaller Use Lossless compression on theme and module images.Wednesday, March 21, 12
  26. 26. Compression Tools ImageOptim - for mac and what I use SmushIt - a web service owned by Yahoo! RIOT - Recommended to me but never used, March 21, 12
  27. 27. Responsive Images • Adaptive Image Note: Does not work with CDNs or reverse proxies. • Responsive Images Uses a special field formatter for images. • Adaptive Image Styles Requires alterations to .htaccess and JS.Wednesday, March 21, 12
  28. 28. Remove Image Styles Metadata ImageMagick advanced module has an option to strip out metadata., March 21, 12
  29. 29. Gzip Everything When you send assets to the browser Gzip everything. Modern browsers (even IE 6) support accepting Gzip compression. • mod_deflate (for apache) • IIS (build in) • HttpGzipModule (nginx)Wednesday, March 21, 12
  30. 30. Part 2: RTT and ConnectionsWednesday, March 21, 12
  31. 31. 6 The number of parallel connections to a domain across all tabs and windows in desktop browsers.Wednesday, March 21, 12
  32. 32. Max Connections Per Host iOS 5 Android 2.2 Android 2.3 Blackberry 6 4 6 5 • Android 2.2 has a 27.8% Android market share. • Android 2.3 has a 58.6% Android market share. • Android 4.x (ICS) has 1% Android market share.Wednesday, March 21, 12
  33. 33. Round-trip Time (RTT) Browser Server “the length of time it takes for a signal to be sent plus the length of time it takes for an acknowledgment of that signal to be received.”, March 21, 12
  34. 34. Mobile phone network latency is 2-10x that of wired connections., March 21, 12
  35. 35. CSS Image Sprites, March 21, 12
  36. 36. CSS Sprite Tools Glue Compass Sprite Cow SpritePad, March 21, 12
  37. 37. Enable CSS and JavaScript Aggregation In an unscientific random poll of DrupalCon attenders websites these were not enabled half the time. Not the first conference I’ve observed this at.Wednesday, March 21, 12
  38. 38. “Adding an Expires header to your components with a date in the future makes them cacheable, reducing the load time of your pages. Certainly this should be done with images, but thats fairly typical. Go a step further and add it to scripts and stylesheets, too. This wont affect performance the first time users hit your page, but on subsequent page views it could reduce response times by 50% or more.”, March 21, 12
  39. 39. What about caching and updating? So, you’ve updated an image or a sprite and you want that to download but your images are set to cache. Solution: Use a custom name for each update. For example append a character you increment or a date. Or, use a query string. This is what Google, Yahoo, and many others do.Wednesday, March 21, 12
  40. 40. Warning: While desktop browsers generally have large caches, mobile browsers typically have a cache only several MB in size.Wednesday, March 21, 12
  41. 41. Part 3: Mobile DevicesWednesday, March 21, 12
  42. 42. 10x JavaScript on mobile devices (high end ones) takes about 10x as long to execute on mobile devices compared to desktop computers.Wednesday, March 21, 12
  43. 43. 512MB The amount of RAM in the iPhone 4s and iPad 2. Mobile devices typically have 1GB or less of RAM. This helps extend battery life.Wednesday, March 21, 12
  44. 44. What Can We Do About It? Nothing Fancy with JavaScript JS has less performance and memory to work with. Simpler DOM A complicated DOM (divitis) uses more system resources. A simpler DOM has less objects in memory. Mobile Optimized Images They use less resources to render, manipulate, and keep in memory.Wednesday, March 21, 12
  45. 45. Let’s Get A Little AdvancedWednesday, March 21, 12
  46. 46. Alternatives To Caching If there isn’t much space to cache where else can we stick assets? Local Storage Google, Bing, and others put assets in local storage. Manifest Appcache Designed for html5 apps these can tell a browser to store assets for long periods.Wednesday, March 21, 12
  47. 47. What Else Can We Compress? JavaScript, CSS, and images aren’t the only things that can be compressed. HTMLCompressor Minify HTML. In Drupal see hook_page_delivery_callback_alter and drupal_deliver_html_page. mod_pagespeed Apache module that automatically optimizes web pages and resources on them.Wednesday, March 21, 12
  48. 48. Delayed JavaScript Evaluation All JavaScript included in a page needs to parsed and evaluated before it becomes available. jQuery on iPhone 4 takes 320ms to parse and evaluate. Lazy Evaluation waits until JS is needed to evaluate it.Wednesday, March 21, 12
  49. 49. Update Your Linux Kernel The Linux 3.3 kernel increases the TCP initial congestion window to 10. This can cut down the number of round trips to get data. Google and Microsoft already do this., March 21, 12
  50. 50. Tools and ResourcesWednesday, March 21, 12
  51. 51. Tools and Resources Page Speed Analyzes a website and generates suggestions. A website or browser plugin. Documentation details on suggestions. Mobile Perf Bookmarklet Tools to analyze on mobile and store data to analyze on desktop. Performance Articles Articles about technologies related to performance.Wednesday, March 21, 12
  52. 52. Chrome Developer ToolsWednesday, March 21, 12
  53. 53. webpagetest.orgWednesday, March 21, 12
  54. 54. Questions? Twitter: @mattfarina Blog: engineeredweb.comWednesday, March 21, 12
  55. 55. What did you think? Locate this session on the DrupalCon Denver website Click the “Take the Survey” link. Thank You!Wednesday, March 21, 12
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