2013 10-02-html5-performance-aarhus
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The document discusses the evolution of computing performance and web application development, highlighting significant advancements in CPU speed, display technology, and network bandwidth over 15 years. It stresses the need for web applications to be optimized for performance, addressing challenges such as loading times and resource management while comparing web apps to native apps. Additionally, it provides practical tips for optimizing web page load speeds and improving overall user experience through effective caching, resource combining, and understanding CSS and JavaScript performance impacts.
![AsImPlEsImUlAtIoNShElLScRiPt
#!/bin/sh!
#!
# simulate_3g.sh - Simulate a sluggish 3G network with delays & packet loss!
# Usage: simulate_3g.sh 8080 8081!
!
# Make sure only root can run our script!
if [[ $EUID -ne 0 ]]; then!
echo "This script must be run as root" 1>&2!
exit 1!
fi!
!
# Simulate http over 3G, 300kbit/s with 5% packet loss and 200ms delays!
# into all ports given as a parameter!
ipfw pipe 1 config delay 200 plr 0.1 bw 300kbit/s!
for var in "$@"!
do!
ipfw add 1 pipe 1 dst-port $var!
done!](https://image.slidesharecdn.com/2013-10-02-html5-performance-aarhus-131008075256-phpapp02/85/2013-10-02-html5-performance-aarhus-19-320.jpg)
2013 10-02-html5-performance-aarhus
- 1. HtMl5 eXpErTiSeaTyOuRsErViCe LaUrISvAn @lAuRiSvAn Sc5OnLiNe @sC5 EnGiNeErInGHtMl5aPpLiCaTiOnS fOr bEtTeR pErFoRmAnCe
- 3. 15YeArSReTrOsPeCtIvEoFMyPeRsOnAlGeAr 1000 tImEstHesPeEdiN15yEaRs CPU Display Connection Network Speed / bps CPU / MFLOPS Pixels 1994 80486 640x480 modem 14,400 3 307,200 1999 AMD Athlon 500 1024x768 ISDN 128,000 180 786,432 2003 AMD Athlon Tbird 1600x1200 cable modem 300,000 373 1,920,000 2010 Intel Core i5 HDMI cable modem 4,000,000 4,256 4,096,000
- 4. 1000tImEs tHeCpU,20tImEstHeBaNdWiDtHtODrAw aPiXeL web pages? slow web pages! pre.y good pages (in desktop)
- 7. WegOtuSeDToCrEaTiNgSlUgGiShWeBSeRvIcEs AttHeSaMetImE,ApPlEdElIvErEd aSlIcKApPExPeRiEnCe ı7 2005 2007 2009 2011 2013 Web 1G Smartphone iPhone PC UsEreXpErIeNcE
- 8. WehAvETrAdEdPeRfOrMaNcEfOrEvErYtHiNgElSe • Distributing the data & computation far away personal computing à web services à mobile & cloud • Consuming increasingly rich data Text à Images à Videos • Moving to highly abstracted & interpreted languages C à Java à JavaScript
- 10. MoBiLeDeViCeS-5yEaRsBaCkiNCpUSpEeD, 10yEaRsBaCkiNCoNnEcTiOnBaNdWiDtH Samsung Galaxy S4 My Machine (2003) My Machine (2010) CPU / MFLOPS 1500 373 4,256 Display / Pixels 2073600 1,920,000 4,096,000 Connection Speed / bps 384000* 300,000 4,000,000 * Assuming 3G/UMTS safe speed, due to low adopNon of 4G networks
- 11. 2005 2007 2009 2011 2013 Web iPhone HTML5 HtMl5&WeBApPsTo ChAlLeNgE NaTiVeApPsiN SlIcKnEsS ı11 UsEreXpErIeNcE UNlizing HW accelerated graphics, offline assets, advanced gestures and high perf JS engines
- 12. LeT’sTaRgEtfOrMoBiLeApPPeRfOrMaNcE • 1s app startup time (first page load time) • 1s for any subsequent view/page (reasonable delay) • 100ms UI response time (noticeable delay) • 16ms paints (LCDs will refresh 50-60Hz, the rest is surplus)
- 13. HTML5 App • 1000 DOM elements • 1Mb of images and 100 network requests on page load How about these? • 1s first page fold Native App • 1000 widgets? • 1Mb of images and 100 network requests on app startup? • 1s application install? WeBeNgInEsaReqUiTe fAsT! LeT’suSetHesAmEyArDsTiCkwHeNmEaSuRiNg
- 14. IfyOuR eMuLaToRrUnS20tImEs fAsTeR tHaN tHeTaRgEt,wHaTcAn yOueXpEcT aBoUtPeRfOrMaNcE?
- 17. OnESeCoNdBuDgEt • Turn on radio 300ms! • DNS lookup + 150ms! • SSL handshake + 200ms! • Process & load HTML & other resources + 200ms! • Parse à Layout à Paint = 150ms!
- 18. SiMuLaTeSlOwPaGeSpEeDs • Developers tend to have ultra-fast computers & networks and forget the Egde & 3G network • Tip: Network Link Conditioner XCode Plugin & ipfw rules
- 19. AsImPlEsImUlAtIoNShElLScRiPt #!/bin/sh! #! # simulate_3g.sh - Simulate a sluggish 3G network with delays & packet loss! # Usage: simulate_3g.sh 8080 8081! ! # Make sure only root can run our script! if [[ $EUID -ne 0 ]]; then! echo "This script must be run as root" 1>&2! exit 1! fi! ! # Simulate http over 3G, 300kbit/s with 5% packet loss and 200ms delays! # into all ports given as a parameter! ipfw pipe 1 config delay 200 plr 0.1 bw 300kbit/s! for var in "$@"! do! ipfw add 1 pipe 1 dst-port $var! done!
- 20. CoMbInEaNdCoMpReSsyOuRReSoUrCeS • Combine and minify your CSS and JavaScript • Combine small icons into a sprite sheet • Squeeze the last bits from your images: It is much easier to remove 100k from your images than your JavaScript code! • Tip: You should automate this, e.g. using Grunt
- 21. CaChInGtHeAsSeTs • CDNs for caching assets close to the user • Varnish, Squid, Nginx etc. in front of your app server • Having the CDNs and caches working requires good headers from your app server, too • Tip: Let your Apache/Nginx reverse proxy care for your headers, they usually do it much better than you do Cache-Control: public, max-age=0 !Etag: "91580-1380653643000“ !Last-Modified: Tue, 01 Oct 2013 18:54:03 GMT!
- 22. ShArDfOrSeVeRaLDoMaInS • Modern browsers limit to 6 connections per host your non- scripted resources (e.g. CSS, images) from several hosts • Severe problem because HTTP 1.1 requires the resources to be sent in the order they were requested • Note: Remember the browser security rules, particularly CORS and Same-origin policy
- 23. If yOuStIlLgOtTiMetOOpTiMiZePaGeLoAdS • Optimize for the first page fold: Critical CSS and JS embeded • Optimize for connection drops & offline: Application Cache • Batch your API calls • Serve responsive images, prepare for the W3C adaptive images extension !<img alt="The Breakfast Combo” src="banner.jpeg” ! !srcset="banner-HD.jpeg 2x, ! !banner-phone.jpeg 100w, ! !banner-phone-HD.jpeg 100w 2x”>!
- 25. OlD-ScHoOlOpTiMiZaTiOnSWoN’tHeLpYoU • JavaScript is typically not your problem • CSS selector lengths typically have only a minor impact • Browsers spend ~90% of its computation layouting and painting What you want to track is • The causes of relayout and repainting • What their costs are • Tip: Watch out adding/removing classes & hovering
- 26. “TyPiCaL PaInTLoOp” FuncNon call / Event Recalculate Style Layout Paint Composite Layers JavaScript Engine (CPU / Virtual Machine) Render Tree & Layout Engine (CPU) Paint Engine (CPU) Compositor (GPU)
- 27. AlL CsSOpErAtIoNsaReN’tEqUaL • Geometry changing ops: Layout, repaint, compositing • width, height etc… • Paint-only ops: Repaint & compositing only • borders, outlines, box shadow, etc… • Composition only (or less): Things that are 100% in GPU • CSS3 Transforms, Opacity
- 28. OpTiMiZiNgLaYoUtS&PaInTs • Avoid DOM reads after geometry changing DOM operations • Avoid a few expensive paint operations (shadows, border radius, flexbox etc…) • Use translateZ(0) hack if you need a HW accelerated element • Use CSS3 transforms for animating, they will not cause reflows
- 30. TrAdItIoNaLPaGeSDoN’tDo aNyThInGuNtIlyOu TeLl *click* *click* Tradi&onal
- 31. ImMeDiAtEFeEdBaCkbUySYoU tImE OvErAlLpErFoRmAnCemAygEtfAsTeR,tOo *click* *click* Feedback
- 32. PrElOaDiNg&BoOtStRaPpInGToShOwtHeNeXtPaGeFaStEr YoUMaYHuRt YoUrSeLfBaD! *click* + *click* Preloading Bootstrapping
- 33. LaZyLoAd -OpTiMiZiNgfOrtHeFiRsTPaGeFoLd + + 1st fold inlined Rest of the page as separate resources + Lazy Load
- 35. ReCaP:GeTtInGtOtHepErFoRmAnCetArGeTs • Set the performance goals, prepare for tradeoffs • Track the goals from the beginning • Don’t guess; measure • Simulate the target performance as part of your daily work • Keep your code simple, don’t trade it for performance • Perfect is the enemy of the good
- 37. HtMl5 eXpErTiSeaTyOuRsErViCe LaUrISvAn ThAnKyOu! Software Architect, SC5 Online Ltd https://github.com/laurisvan https://twitter.com/laurisvan