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Practical web performance - Site Confidence Web Performance Seminar

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Over of Web performance optimisation (WPO) as well as some results from 25 web performance site analysis. Some information on Mobile web performance as well.

Over of Web performance optimisation (WPO) as well as some results from 25 web performance site analysis. Some information on Mobile web performance as well.

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  • Very Subjective!!! Perceived… because perception is crucial (as we shall see)Action to Response – from “here to here” – ie any delay experienced has a context of what the customer’s intention is…Meaningful Response – spinners are good, but people won’t wait forever… Different for different sites – for different users (Age, Gender, emotional state (“Is the train about to leave, I’m running late”?), culture, level of experience) – at different stages in the user journey (e.g Navigation browser vs Search vs checkout) Different devices? – Mobile vs wireless vs wired?
  • Stoyan’s Talk at Velocity “The Psychology of Performance” http://velocityconf.com/velocity2010/public/schedule/detail/13019"Satisfaction = perception minus expectation" - David Maister
  • In fact, your performance could be “stressing them out”….
  • This is from the Foviance/ CA Study http://www.foviance.com/what-we-think/its-official-web-stress-is-bad-for-business-2/ http://www.ca.com/Files/SupportingPieces/final_webstress_survey_report_229296.pdf
  • The 3 response-time limits are the same today as when I wrote about them in 1993 (based on 40-year-old research by human factors pioneers): 0.1 seconds gives the feeling of instantaneous response — that is, the outcome feels like it was caused by the user, not the computer. This level of responsiveness is essential to support the feeling of direct manipulation (direct manipulation is one of the key GUI techniques to increase user engagement and control — for more about it, see our Principles of Interface Design seminar). 1 second keeps the user's flow of thought seamless. Users can sense a delay, and thus know the computer is generating the outcome, but they still feel in control of the overall experience and that they're moving freely rather than waiting on the computer. This degree of responsiveness is needed for good navigation. 10 seconds keeps the user's attention. From 1–10 seconds, users definitely feel at the mercy of the computer and wish it was faster, but they can handle it. After 10 seconds, they start thinking about other things, making it harder to get their brains back on track once the computer finally does respond.
  • As measured @ 2Mbps in IE8…But the actual download speed and browser are irrelevant… this is about user perception… so the real question is “which customers do I want to have a good perception of my site…”
  • Can anyone guess why performance matters?
  • Front-end – between browser and data centreBack-end – generating the response on the server
  • http://code.google.com/speed/page-speed/docs/rules_intro.html
  • A review of 25 web performance optimisation engagements performed by Site Confidence over the last 12 months.
  • Load time correlation from the HTTP Archive
  • Render time correlation from the HTTP Archive
  • Based on 25 consulting reports across a wide range of e-commerce and publishing sites
  • 100% of the time there were too many requests100% of the time they weren’t using caching to its full advantage, and hence repeat visits were slower than they needed to be…76% of the sites exhibited noticable slowing down during peak time of day/week~50% of the time the pages were bloated (often due to images that on average can be optimised ~15%) Frighteningly ¼ of the sites analysed either didn’t have Gzip compression enabled or it had problems e.g. failing under load!
  • The MSN performance talk was excellent http://velocityconf.com/velocity2011/public/schedule/detail/18039Performance improvements can increase and DECREASE your bottom line so be careful!
  • In fact this is an example where it took 30 secsIt’s also crappy JavaScript and a poor page design…
  • 100ms latency on each request = 5 sec page slowdown on a page100ms is about the latency you would get from here to the US…
  • [Next Slide…]But what about “the bigger picture”? Being successful in WPO is more than just “implementing the rules”… so what else can we learn from the experiences of others?
  • KeepAliveTimeout DirectiveDescription:Amount of time the server will wait for subsequent requests on a persistent connectionSyntax:KeepAliveTimeout secondsDefault:KeepAliveTimeout 5MaxKeepAliveRequests DirectiveDefault:MaxKeepAliveRequests 100 MaxKeepAliveRequests directive limits the number of requests allowed per connection when KeepAlive is on. If it is set to 0, unlimited requests will be allowed. We recommend that this setting be kept to a high value for maximum server performance.For example:MaxKeepAliveRequests 500
  • It’s about measurement…
  • WPO Performance isn’t just for Christmas…It’s an on-going effort…
  • Just like an ITIL implementation…
  • So you need these 8 skills (at a minimum) contributing to your web performance process…But if you are a small startup these all might be one person…Performance Lead / EvangelistFront-end DeveloperBack-end DeveloperPerformance QADatabase AdministratorSystems AdministratorNetwork AdministratorWeb Analytics Analyst
  • So a team like that, even part-time, is going to cost you money…… but there are ways to automate it with both commercial (e.g. Aptimize) and open-source (Google’s Mod_pagespeed)What works for you depends on the size and scale of your website, your available resources, etc. OpexvsCapex… Probably a hybrid approach is best – automate where it’s cost-effective, hand-tune the important bits.
  • What else? Let’s hear from Lord Kelvin…
  • http://www.webperformancematters.com/journal/2007/5/7/the-importance-of-measurements.html
  • An dyou can use those measurements as a differentiator in your business!!! – See Betfair’s Performance Charter…This doesn’t have to be esoteric backroom stuff!
  • Don’t be afraid to make some noise about it!!! Use it as a BHAG and as a point of differentiation to your competitors!
  • Just a reminder…. For those that were paying attention earlier! So how can we measure web performance…
  • There are basically 6 techniques used to measure web performance:Each one has it’s pros and cons… easy of use, what it can measure, cost etc
  • Operations has different needs to Marketing or User Experience team
  • Notethat active monitoring can use either an synthetic agent or a “real browser”Passive – the signal to noise ratio is huge, just like passive sonar. Trying to detect the signal from the clutter is very hard… Anyway, enough about all the WPO projects, what about the
  • It’s about measurement…
  • This is from 2009 so it’s out of date BUT it makes the point that “which measurement do you choose”http://sixrevisions.com/infographics/performance-comparison-of-major-web-browsers/Aug 2011 data here - http://www.tomshardware.com/reviews/web-browser-performance-standard-html5,3013.html
  • It’s about measurement…
  • And if you throw in CyanogenMod you can get even better performance…
  • Whilst its growing fast… From Souders preso - http://www.slideshare.net/souders/high-performance-mobile-sfsv-web-perf
  • From Souders preso - http://www.slideshare.net/souders/high-performance-mobile-sfsv-web-perfObviously this is heavily influenced by sector…e.g. the Adactus guys can tell you about Pizza Hut who do very nicely on mobile!Ditto for music, ringtones etc.
  • I was on the Thames Clipper on my way back from the O2 after a concert. So I ran some automated testing and this graphs my results… on the Velocity Conference home page…Min9.275Max156.520Average32.859Median12.071Std Deviation45.691
  • Network latency varies enormously…. What can we see here?The connection is relatively good at sending and receiving data. The green crosses represent packets that were actually lost which only happened for 75 of 1000.There are some crazy-high round trip times. The minimum round trip time was 107ms (which would put my home cable connection to shame) and even the median is pretty awesome at 239ms but the maximum was a whopping 20226 ms - that's more than 20 seconds!
  • But before I go… two quick plugs…
  • Transcript

    • 1. Practical Web performance
      Stephen Thair, Seriti Consulting, @TheOpsMgr
      stephen.thair@seriticonsulting.com
      26/09/2011
      © Seriti Consulting
      1
    • 2. Defining “Web Performance”?
      Why performance matters (to your business)
      The “Rules” of Web Performance
      Practical Web Performance (“where to start!”)
      Agenda
      26/09/2011
      (c) Seriti Consulting, 2011
      2
    • 3. My Definition of Web Performance
      26/09/2011
      (c) Seriti Consulting, 2011
      3
      “The delay perceived by the website visitor between an action (e.g click) and a meaningful response”
      “The delay perceived by the website visitor between an action (e.g click) and a meaningful response”
      “The delay perceived by the website visitor between an action (e.g click) and a meaningful response”
    • 4. Perception
      http://velocityconf.com/velocity2010/public/schedule/detail/13019
      26/09/2011
      (c) Seriti Consulting, 2011
      4
    • 5. 26/09/2011
      © Seriti Consulting
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      Just because your DevMgr, QA Mgr, Ops Mgr tells you “performance is good” doesn’t means that it is PERCEIVED that way by your CUSTOMERS…
    • 6. “Brain wave analysis from the experiment revealed that participants had to concentrate up to 50% more when using badly performing websites, while facial muscle and behavioural analysis of the subjects also revealed greater agitation and stress in these periods.
      http://www.ca.com/Files/SupportingPieces/final_webstress_survey_report_229296.pdf
      Poor Performance = Web Stress!!!
      26/09/2011
      (c) Seriti Consulting, 2011
      6
    • 7. 0.1 secondsgives the feeling of instantaneous response
      1 secondkeeps the user's flow of thought seamless.
      10 secondskeeps the user's attention
      JakobNeilsen. http://www.useit.com/alertbox/response-times.html
      So what is “Good Performance”?
      26/09/2011
      (c) Seriti Consulting, 2011
      7
    • 8. 10 Seconds is too slow… (IMHO)
      “Initial render” < 750ms and be
      “Page Complete” < 3 seconds
      “3 Second Rule”
      26/09/2011
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      8
    • 9. Why Performance Matters
      26/09/2011
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      9
    • 10. Bounce Rate goes up
      http://www.webperformancetoday.com/2010/06/22/the-90-minute-optimization-life-cycle-faster-by-default-before-our-eyes/
      26/09/2011
      (c) Seriti Consulting, 2011
      10
    • 11. Page Views goes down
      http://www.webperformancetoday.com/2010/06/22/the-90-minute-optimization-life-cycle-faster-by-default-before-our-eyes/
      26/09/2011
      (c) Seriti Consulting, 2011
      11
    • 12. Conversion Rate goes down
      http://www.webperformancetoday.com/2010/06/22/the-90-minute-optimization-life-cycle-faster-by-default-before-our-eyes/
      26/09/2011
      (c) Seriti Consulting, 2011
      12
    • 13. “A 1-second delay in page load time equals 11% fewer page views, a 16% decrease in customer satisfaction, and 7% loss in conversions”
      Aberdeen Group
      http://www.aberdeen.com/Aberdeen-Library/5136/RA-performance-web-application.aspx
      3rd Party Research
      26/09/2011
      (c) Seriti Consulting, 2011
      13
    • 14. Artificial 1s delay = 2.8% reduction in revenue per user
      Empirical Testing
      26/09/2011
      (c) Seriti Consulting, 2011
      14
      http://assets.en.oreilly.com/1/event/29/The%20User%20and%20Business%20Impact%20of%20Server%20Delays%2C%20Additional%20Bytes%2C%20and%20HTTP%20Chunking%20in%20Web%20Search%20Presentation.pptx
    • 15. You are losing Visitors
      You are losing Sales
      You are losing Ad-revenue
      You are wasting SEO/SEM/PPC budget
      Spending £££ on bandwidth and servers
      In Summary…
      26/09/2011
      (c) Seriti Consulting, 2011
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    • 16. 26/09/2011
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      So how are we doing?
    • 17. 26/09/2011
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      Largest Page…
      4,909,588 bytes
    • 18. 26/09/2011
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      Slowest Page…
      12.436 secs
    • 19. 26/09/2011
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      Most objects…
      227
    • 20. 26/09/2011
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      1 was down for maintenance
      1 didn’t re-direct from http to https
      ~28% had some type of error
    • 21. 26/09/2011
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      So what can you do about it?
      Answer = Optimise!
    • 22. 26/09/2011
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      80% “Front End”
      20% “Back-end”
    • 23. Focus on the “front end”
      Optimise the interaction between the browser and the data-centre
      And how the browser processes the client-side objects
      “Front End Engineering”
      26/09/2011
      (c) Seriti Consulting, 2011
      23
    • 24. Yahoo’s Rules
      • Minimize HTTP Requests
      • 25. Use a Content Delivery Network
      • 26. Add an Expires or a Cache-Control Header
      • 27. Gzip Components
      • 28. Put StyleSheets at the Top
      • 29. Put Scripts at the Bottom
      • 30. Avoid CSS Expressions
      • 31. Make JavaScript and CSS External
      • 32. Reduce DNS Lookups
      • 33. Minify JavaScript and CSS
      • 34. Avoid Redirects
      Remove Duplicate Scripts
      Configure ETags
      Make AJAX Cacheable
      Use GET for AJAX Requests
      Reduce the Number of DOM Elements
      No 404s
      Reduce Cookie Size
      Use Cookie-Free Domains for Components
      Avoid Filters
      Do Not Scale Images in HTML
      Make favicon.ico Small & Cacheable
      http://developer.yahoo.com/yslow/help/#guidelines
      26/09/2011
      (c) Seriti Consulting, 2011
      24
    • 35. Google’s Rules
      • Avoid bad requests
      • 36. Avoid CSS expressions
      • 37. Combine external CSS
      • 38. Combine external JavaScript
      • 39. Defer loading of JavaScript
      • 40. Enable compression
      • 41. Leverage browser caching
      • 42. Leverage proxy caching
      • 43. Minify CSS
      • 44. Minify HTML
      • 45. Minify JavaScript
      • 46. Minimize request size
      • 47. Minimize DNS lookups
      Minimize redirects
      Optimize images
      Optimize the order of styles and scripts
      Parallelize downloads across hostnames
      Put CSS in the document head
      Remove unused CSS
      Serve resources from a consistent URL
      Serve scaled images
      Serve static content from a cookieless domain
      Specify a character set early
      Specify image dimensions
      Use efficient CSS selectors
      http://code.google.com/speed/page-speed/docs/rules_intro.html
      26/09/2011
      (c) Seriti Consulting, 2011
      25
    • 48. 26/09/2011
      © Seriti Consulting
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      Informationoverload!
    • 49. 26/09/2011
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      Where should you start?
    • 50. 26/09/2011
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      Which optimisations are most common?
      Which optimisations are most important?
      And the survey says…
    • 51. HTTP Archive - Load Time Correlation
      26/09/2011
      © Seriti Consulting
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      http://httparchive.org/interesting.php
    • 52. HTTP Archive - Render Time Correlation
      26/09/2011
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      http://httparchive.org/interesting.php
    • 53. Lessons learnt from consulting…
      26/09/2011
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    • 54. 26/09/2011
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    • 55. 5 Important Ones
      Reduce Page Size (<500Kb)
      Enable (Gzip) Compression
      Reduce the number of roundtrips (<40 per page…)
      HTTP Cache Headers (cache long & prosper!)
      Structure the page (to improve render & download)
      CSS First
      Javascript last
      26/09/2011
      (c) Seriti Consulting, 2011
      33
    • 56. Even if you apply just those 5 rules…Your page download times will drop by ~50%
      Low hanging fruit…
      26/09/2011
      (c) Seriti Consulting, 2011
      34
    • 57. What about the other rules?
      Generally you are now measuring gains in milliseconds
      26/09/2011
      (c) Seriti Consulting, 2011
      35
      But even milliseconds can make a difference…
    • 58. Optimising JavaScript & async loading
      26/09/2011
      © Seriti Consulting
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      Loading jqueryAsync
      Improving JS Execution time
      Delayed ad-loading
      Faster does not always equal more revenue!!!
      http://velocityconf.com/velocity2011/public/schedule/detail/18039
    • 59. “Reduce the number of DOM elements”
      26/09/2011
      (c) Seriti Consulting, 2011
      37
      24,000 calls to a selector takes time…
    • 60. “Use a content delivery network”
      26/09/2011
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      You can’t beat the speed of light…
      And if your customers are not in the UK, invest in a CDN…
    • 61. 26/09/2011
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      4.5 seconds in London
      becomes
      12.5 seconds in Singapore
    • 62. “Use http keep-alives”
      26/09/2011
      © Seriti Consulting
      40
      Tune your HTTP Keep-Alives!
      KeepAliveTimeout Value (sec)
      MaxKeepAlive Requests (# requests/connection)
      Stop forcing your customers to re-negotiate connections (even partway through a page!)
      Even more important for SSL! (~4x slower)
    • 63. 26/09/2011
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      “The Bigger Picture”
    • 64. 26/09/2011
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      WPO is not just for Christmas…
    • 65. 26/09/2011
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      Performance is a
      PROCESS
      NOT a
      PROJECT
      http://www.seriticonsulting.com/blog/2011/5/28/web-performance-is-not-just-for-christmashellip.html
    • 66. 26/09/2011
      © Seriti Consulting
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      Who should you have on your
      WPO project
      team?
      http://www.seriticonsulting.com/blog/2011/5/29/who-should-be-on-your-wpo-team.html
    • 67. 26/09/2011
      © Seriti Consulting
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      Who should you have on your
      WPO Process!
      team?
      http://www.seriticonsulting.com/blog/2011/5/29/who-should-be-on-your-wpo-team.html
    • 68. 26/09/2011
      © Seriti Consulting
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      Performance Lead / Evangelist
      Front-end Developer
      Back-end Developer
      Performance QA
      Database Administrator
      Systems Administrator
      Network Administrator
      Web Analytics Analyst
    • 69. 26/09/2011
      © Seriti Consulting
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      Economics of WPO… is automation the answer?
      http://www.seriticonsulting.com/blog/2011/8/11/why-i-think-automation-is-the-future-of-webperf.html
      Answer: Maybe?
    • 70. 26/09/2011
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      What Else?
    • 71. 26/09/2011
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      “I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of Science, whatever the matter may be.”
      -- William Thomson,1st Baron Kelvin
    • 72. 26/09/2011
      © Seriti Consulting
      50
      Make sure you can measure your website performance…
      (and that the numbers are getting better, not worse!)
    • 73. Betfair’s customer performance charter
      26/09/2011
      © Seriti Consulting
      51
       ”We aim for 99.9% of bets placed in less than a second and our aspirational website SLA is as follows. Under peak loads, with performance measured at the 95th percentile, for typical user bandwidths and a 0% error rate, our users shall experience Visual Progress (header loaded) in less than 1 second, Time to Interact with useful content within 1.5 seconds and full page loads within 3 seconds. (There is room for improvement on this front as our current sports home page loads in approx. 18 seconds at the 95th percentile). We will publish our aggregate stats here monthly.”
      http://www.seriticonsulting.com/blog/2011/7/20/creating-an-performance-sla-with-your-customers-betfairrsquo.html
    • 74. 10 Seconds is too slow… (IMHO)
      “Initial render” < 750ms and be
      “Page Complete” < 3 seconds
      “3 Second Rule”
      26/09/2011
      (c) Seriti Consulting, 2011
      52
    • 75. JavaScript timing e.g. WebTuna, GA SiteSpeed
      Browser plug-in e.g. HTTPwatch
      Custom browser e.g. Site Confidence Active
      Proxy timing e.g. Fiddler proxy
      Web Server Module e.g. APM solutions
      Network-level e.g. SC Organic, Atomic Labs Pion
      26/09/2011
      (c) Seriti Consulting, 2011
      53
      6 ways of measuring WebPerf
    • 76. 26/09/2011
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      Which is better?
      It Depends…
    • 77. Do you want to measure every visit to your website?
      Use a jscript tag, web server or network level solution
      Are you measuring as part of Dev or QA?
      Use a browser plug-in or proxy
      Do you want detailed browser metrics like render start time?
      Use a browser plug-in
      Are you a 3rd party monitoring provider?
      Use a custom browser variant!
      26/09/2011
      (c) Seriti Consulting, 2011
      55
      It depends on…
    • 78. Active Monitoring
      Agent “pings” the web page
      “Real-User” Monitoring (RUM)
      “listening in” to real user traffic
      Complementary methods!
      Best solution is Active & Real-User
      Not Active or Real-User…
      26/09/2011
      (c) Seriti Consulting, 2011
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      Active vs “Real-User”
    • 79. 26/09/2011
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      What about client-side?
    • 80. The Browser performance wars…
      26/09/2011
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      http://sixrevisions.com/infographics/performance-comparison-of-major-web-browsers/ (2009)
    • 81. Automate cross-Browser perf testing!
      26/09/2011
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    • 82. 26/09/2011
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      What about Mobile?
    • 83. Different operating systems
      26/09/2011
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    • 84. Even more browsers?
      26/09/2011
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      http://www.webdevelopersnotes.com/articles/mobile-web-browsers-list.php
    • 85. slideshare.net/CMSummit/ms-internet-trends060710final
    • 86. 26/09/2011
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      http://www.nytimes.com/2011/04/18/technology/18mobile.html
    • 87. Mobile Performance is location-dependent
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      http://mytests.3pmobile.com/context/?WyIyUFVDZHlWV2ErZHFISmxCSWFXRENnPT0iLCJEYnFYVVp3SEN4MD0iXQ%3D%3D
    • 88. Mobile latency (over HSDPA)
      26/09/2011
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      Max RTT = 20 seconds!
      http://blog.davidsingleton.org/mobiletcp
    • 89. Mobile performance rules???
      Latency kills…
      DNS Lookups take far longer
      Avoid re-directs (to http://m.yourdomain.com)
      Reduce the number of roundtrips (<15 per page?)
      26/09/2011
      (c) Seriti Consulting, 2011
      67
    • 90. Mobile performance rules???
      “Intelligent Adaptation”
      Be device & network aware!
      Send only what you need
      Send the right sized images
      With the minimum of script/CSS/etc
      26/09/2011
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    • 91. Mobile performance rules???
      Cache
      Brower cache (small cache, with a different eviction algorithm…)
      AppCache,
      LocalStorage,
      26/09/2011
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    • 92. 26/09/2011
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      And that’s all I’ve got…(but before I go…)
    • 93. 26/09/2011
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      Velocity EU
      Web Performance Conference
      Berlin 8th/9th November
      (see me for a discount code!)
      http://velocityconf.com/velocityeu/