extreme web performance for mobile devices - velocity barcelona 2014
DESCRIPTION
Slides for the workshop "Extreme Web Performance for Mobile Devices" at Velocity Barcelona 2014TRANSCRIPT
extreme web performance for mobile devices
maximiliano @firtman firt.mobi
Barcelona, Nov 19 2014
NEW!SOON!
Slides, links and tests firtman.github.io/velocity
questions
yes, please
QA at the end
(en español también)
performance + mobile + web
1- Mobile Web today 2- Performance & Mobile 3- Tools 4- Initial loading & perception 5- Responsiveness & experience
1- mobile web today*
*today: november 2014
1- mobile web today
- Web Platforms - The Android’s problem
web platforms
iOS and Android
web platforms
Adobe Digital Index NetMarketShare Akamai.io Wikimedia Stats StatCounter MOVR by WURFL
web platformsLinks at firtman,github.io/velocity
web platformsOthers
4%
Windows Phone 3%
Opera 5%
iOS50%
Android38%
web platforms
iOS50%
Safari100%
web platforms
iOS50%
Apps (Web View) 12%
Safari88%
web platforms
iOS50%
7.x 40%
6.x5%
8.x55%
Source: Apple
web platforms
InApp iOS 5%
Safari iOS720%
Safari iOS825%
Android38%
web platforms
Android38%
web platforms
Android38% Browser
60%
Chrome40%
1% month
web platforms
web platforms
web platforms
LG G3
web platforms
Android38%
Samsung20%
Browser40%
Chrome40%
web platforms
iOS50%
Android38%
web platforms
Samsung10%
Android15%
Others4%
Windows Phone 3%
Opera 5%InApp iOS
5%
Safari iOS720%
Safari iOS825%
Chrome14%
Others?
• Firefox • UC Browser • Nokia Browser • BlackBerry Browser
1- mobile web today
- Understand the real ecosystem - Android browsers - Don’t think you are an average user - May change future
2- mobile & performance
- Perception - Differences - Cellular networks - Responsive Web Design
immediate feedback 100ms
perception
Jakob Nielsen - Usability Engineering
immediate feedback 100ms
losing user’s flow of thoughts 1s
perception
Jakob Nielsen - Usability Engineering
500ms delay, +26% user’s frustration
perception
Source: Radware
why do we need special care on mobile?
CPU and GPU
Memory
differences
CPU and GPU
Memory
differences
5x
Wifi
differences
Wifi, public spaces?
differences
Cellular connections
differences
We have 4G! We don't need to worry about performance...
(
)
cellular
0
25
50
75
100
US Western Europe Asia Global
4G 2G/3G
Only 4% is on 4G globally
cellular
0
25
50
75
100
US Western Europe Asia Global
4G 2G/3G
~30% of the time 4G was not used
Real Bandwidth (Mbps)cellular networks
0 2 4 6 8
2G 3G Wifi 4G
RTT - latencycellular networks
2G
3G
4G
Home
0 250 500 750 1000
Min Max
latency
request
bandwidth
Safari, Chrome, Android 71%91%
1%
7%
18%
Other non-Android, non-iOS 10%
Safari, Chrome, Android 71%91%
responsive web design
Responsive Web Design is a TOOL
Responsive Web Design is NOT a GOAL
Users DON’T care if your site is RESPONSIVE
(in terms of RWD)
Users DO care if the site is FAST
Page size
mobile vs desktop
responsive web design
Much smaller6%
Slightly smaller22%
Same Size72%
Source: guypo.com
Superbowl advertisers
mobile approach
responsive web design
Responsive site50%
Desktop7%
Mobile 43%
Source: blogs.keynote.com
2- mobile and performance
- Perception: 1s threshold - RTT latency - Test on low hardware and 2G/3G
3- tools
3- tools- where - measuring loading times - measuring responsiveness - online tools - html5 apis
Simulator & Emulator
Real device
where
emulators
Samsung10%
Android15%
Others4%
Windows Phone 3%
Opera 5%
InApp Browser iOS 5%
Safari iOS45%
Chrome14%
emulators
Samsung10%
Android15%
Others4%
Windows Phone3%
Opera 5%
InApp Browser iOS 5%
Safari iOS45%
Chrome14%
emulators
Samsung10%
Android15%
Others4%
Windows Phone 3%
Opera 5%
InApp Browser iOS 5%
Safari iOS45%
Chrome14%
DEMO
online tools
online tools
online tools
online tools
remote inspectors
remote inspectors
Samsung10%
Android14%
Others4%
Windows Phone3%
Opera 5%
InApp Browser iOS 5%
Safari iOS45%
Chrome15%
Measuring
DEMO
Proxies / Network sniffers
• Charles Proxy • Fiddler
tools
Image from telerik fiddler
Connection simulators
• Network link conditioner (Mac/iOS) • Charles Proxy • Clumsy for Windows • Net Limiter for Windows • SlowyApp for Mac • Chrome Developer Tools
tools
html5 apis
Navigation Timing API
• window.performance • Timestamps available
html5 apis
navigation timing api
Samsung12%
Android*12%
Others4%
Windows Phone3%
Opera 5%
InApp Browser iOS5%
Safari iOS45%
Chrome15%
* Android browser only from 4.0
Navigation Timing APIhtml5 apis
:)
Navigation Timing APIhtml5 apis
:/.1
iOS SDK Release Notes for iOS 8.1html5 apis
Navigation Timing APIhtml5 apis
DEMO
Resource Timing API• Information per resource • Chrome and IE11 only
html5 apis
Network information API
• Android Browser, Silk (spec #1) type • BlackBerry 10, old Firefox (spec #2) bandwidth • Firefox, Chrome for Android 38+ (spec #3) type
html5 apis
3- tools
- Learn where to test - Measure loading times - Measure responsiveness - HTML5 APIs
4- initial loading & perception
4- initial loading & perception- 1 second threshold - classic checklist - ATF and the rest - responsive web design - future visits
What!!? Do you expect a page load in 200ms?
(
)
No really, we just need the PERCEPTION
Let’s see HOW
= REDIRECTS
Redirects
• From 150 to 1000 ms per redirect • mydomain.com -> m.mydomain.com • URL shorteners
Redirects
DEMO
= APP BANNER
= APP SPAM
• From 1 to 5s
Basic browser behavior
• Network Fetch • Parsing • Rendering
Basic browser behavior
HTML
JS CSS
Basic browser behavior
HTML
JS CSSBLOCKS PARSING BLOCKS RENDERING
The 14K limit
The 14K limit
• TCP slow start • Initial congestion window: ~14.6Kb (compressed) • > 14Kb will create another roundtrip
RTT
We need to separate ABOVE THE FOLD (ATF)
content
ATF in 1s = 1 RTT ~ < 14Kb
HTML + CSS + JavaScript Images?
ATF
Avoid JavaScript frameworks
• Embrace Vanilla JS • If you really need them, load them after ATF • Think on alternatives or partial frameworks
ATF
Careful with Data URI in CSS
• Images are non-blocking by default • Using Data URI in CSS creates blocking images • Use them only on non-ATF external CSS
ATF
Compress resources
• Use Gzip in HTTP • For text-based files only
Client side rendering
• Careful with client-side frameworks • Try to render the initial view server-side • Render at least a basic view
ATF
Client side rendering
• Careful with client-side frameworks • Try to render the initial view server-side • Render at least a basic view
ATF
5x
Web Fonts• Blocks text rendering • Fonts are bigger than 14Kb • Use them with care • Remove characters • Simplify glyphs
ATF
Responsive Web Design
Responsive Web Design
• Media queries block rendering (all of them) • ATF content on mobile is not the same
DON’T rely on RWD techniques only
for first view
RESPONSIVE WEB DESIGN is the future
We are not saying go m.*
Responsive Web Design
• Using same URL for mobile/desktop still a good a idea • Mix it with RESS / adaptive web design • Load media queries CSS async • Use server-side libraries • WURFL or DeviceAtlas
After ATF is ready
• Load rest of your content • Gain experience while rendering ATF: current performance, screen density, bandwidth • Make decisions: HD/SD
Async scripts
<script async src=""></script> HTML5
Defer non-ATF CSS
• No defer or async attributes (yet) • Inject <link> after rendering • load, requestAnimationFrame
Speed future visits
• Be cache friendly • Use Application Cache for ATF content • Create a custom cache
4- initial loading & perception
- ATF in 1s (illusion) - No redirects, GZip, no scripts - Only ATF CSS, careful with fonts - Defer anything else
5- responsiveness & experience
4- responsiveness & experience
- consistent frame rate - immediate feedback - scrolling - your new enemy
Keep framerate high and consistent
• Main UI thread as free as possible • Avoid repainting (software bitmap calculations)
consistent fps
JavaScriptframerate
• Avoid DOM manipulations inside loops/scroll
var e = document.querySelector("#test");for (var i=0; i<100; i++) { // change e attributes });
JAVASCRIPT
CSSframerate
• Promote GPU layers smartly selector {
-webkit-transform: translateZ(0); -webkit-perspective: 1000; }
selector { z-index: 10; }
CSS
Animationsframerate
• Don’t animate from JavaScript for basic stuff • Use requestAnimationFrame
remember 100ms immediate feedback?
Immediate feedback
• The 300ms delay
• mobile viewport (“user-scalable=no” on some browsers) • FastClick solution
Immediate feedback
• FastClick solution
Immediate feedback
• Mobile Viewport on Chrome
<meta name=viewport content="width=device-width">
HTML
Immediate feedback
• Mobile Fixed Viewport on IE <meta name=viewport content="width=device-width, user-scalable=no" >
HTML
Immediate feedback
• CSS on IE html { -ms-touch-action: manipulation; touch-action: manipulation; }
CSS
Distract the user
Storage for immediate feedback
• web storage vs web sql vs indexeddb • think about async vs sync • Finally IndexedDB on iOS 8!
navigator.geolocation .getCurrentPosition(cbOK, cbKO, { maximumAge: 60000 });
JAVASCRIPT
Geolocation cache
Scrolling
Scrolling
• avoid re-painting • use touch overflow for momentum • don’t use JavaScript scrollers • on large scrolling areas: copy native
Large scrolling areas
Let’s copy native frameworks: • iOS: UITableView • Android: ListView & Adapters
Large scrolling areas
• Object pool
Infinite scroll
• DOM vs. iframe vs. object pool • changes on iOS8
Your new enemy
NOT THE USER
YOUR DESIGNER
Careful with some design features
• GPU vs CPU repaint • Important on scroll, transitions & animations
Careful with some design features
• Transforms: translate, scale, rotate and opacity GPU • border-radius, gradients, shadows, filters CPU repaint
5- responsiveness & experience- 100s feedback - Consistent fps - Avoid CPU repaints - Embrace GPU smartly - Profile & test
Picture from Simon Howden freedigitalphotos.net!
Picture from Simon Howden freedigitalphotos.net!
uf! we've covered a lot!
1- Mobile Web today 2- Mobile Performance 3- Tools 4- Initial load & perception 5- Responsiveness & experience
Slides, links and tests firtman.github.io/velocity
final thoughts
- measure and profile on the real world - don’t redirect, reduce requests - atf content in 1s, defer the rest - be simple, be aggressive
you can reach a good experience
Pictures)from)freedigitalphotos.net)
[email protected]@firt
firt.mobi/pmw firt.mobi/mh5
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