extreme web
performance for
mobile devices
maximiliano @firtman
firt.mobi

Slides, links and tests
firt.mobi/velocity

questions
yes, please
!
QA at the end

performance + mobile + web
1- Mobile Web today
2- Performance & Mobile
3- Tools
4- Initial loading & perception
5- Responsiveness & experience

1- mobile web today*
*today: june 2014

1- mobile web today
- Web Platforms
- The problem of Android
- Webapps

web platforms

iOS and Android
web platforms

Adobe Digital Index
NetMarketShare
Akamai.io
Wikimedia Stats
StatCounter
web platformsLinks at firt.mobi/velocity

web platformsOthers
4%
Windows Phone
3%
Opera
5%
iOS!
50%
Android!
38%

web platformsOthers
4%
Windows Phone
3%
Opera
5%
iOS!
50%
Android!
38%
Others?
• Firefox
• UC Browser
• Nokia Browser
• BlackBerry Browser

web platforms
iOS!
50%
Safari!
100%

web platforms
iOS!
50%
6.x!
11%
7.x!
89%
Source: Apple

web platforms
Safari iOS6
5%
Safari iOS7!
45%
Android!
38%

web platforms
Android!
38%

web platforms
Android!
38%
Browser!
64%
Chrome!
36%

web platforms

web platforms

web platforms
Android!
38%
Samsung!
32%
Browser!
32%
Chrome!
36%

web platforms
Android!
38%
4.4
4.1-4.3
4.0
2.3
Source: Android Dashboard

web platformsOthers
4%
Windows Phone
3%
Opera
5%
iOS!
50%
Android!
38%

web platforms
Samsung!
12%
Android!
12%
Others
4%
Windows Phone
3%
Opera
5%
Safari iOS6
5%
Safari iOS7!
45%
Chrome!
14%
Others?
• Firefox
• UC Browser
• Nokia Browser
• BlackBerry Browser

in a month… new phone

future

future

future

future

it’s not just about
browsers

webapps

full screen webapps
home screen webapps
webapps are also known as(
)

webapps
Browser’s engine!
1- Web.app (~Safari) on iOS
2- Chrome on Android
3- Firefox on Android and FxOS

webapps
native webapps

hybrid apps
packaged webapps
native webapps are also known as(
)

webapps
Web View

webapps
Web View on iOS
!
1- UIWebView on iOS 7
2- WKWebView on iOS 8

webapps
Web View on Android!
1- WebKit from 2.x to 4.3
2- Chromium 30 on 4.4
3- Chromium on Samsung
4- Chromium on Fire OS

webapps
Web View on Windows
!
1- IE 10 on Windows (Phone) 8
2- IE 11 on Windows (Phone) 8.1

1- mobile web today
- Understand the real ecosystem
- Android browsers
- Don’t think you are an average user
- Webapp solutions
- May change future

2- mobile & performance
- Perception
- Differences
- Cellular networks
- Responsive Web Design
- Some data

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

“page slowdowns negatively affected
people’s long-term impression of the
entire brand”
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 2.2% is on 4G globally

cellular
0
25
50
75
100
US Western Europe Asia Global
4G 2G/3G
~40% of the time 4G was not used

Real Bandwidth (Mbps)
cellular networks
0 2 4 6 8
2G 3G Wifi 4G

RTT - latency
cellular networks
2G
3G
4G
Home
0 250 500 750 1000
Min Max

latency
request
bandwidth

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 smaller!
6%
Slightly smaller!
22%
Same Size!
72%
Source: guypo.com

Superbowl advertisers
mobile approach
responsive web design
Responsive site!
50%
Desktop!
7%
Mobile !
43%
Source: blogs.keynote.com

2- mobile and performance
- Perception: 1s threshold
- RTT latency
- Test on low hardware and 2G/3G
- Responsive Web Design
!

3- tools

3- tools
- where
- measuring loading times
- measuring responsiveness
- online tools
- html5 apis

Simulator & Emulator
Real device
where

emulators
Samsung!
12%
Android!
12%
Others!
4%
Windows Phone
3%
Opera
5%
Safari iOS6
5%
Safari iOS7!
45%
Chrome!
14%

emulators
Samsung!
12%
Android!
12%
Others!
4%
Windows Phone!
3%
Opera
5%
Safari iOS6
5%
Safari iOS7!
45%
Chrome!
14%

emulators
Samsung!
12%
Android!
12%
Others!
4%
Windows Phone
3%
Opera
5%
Safari iOS6
5%
Safari iOS7!
45%
Chrome!
14%

DEMO

online tools

online tools

remote inspectors

remote inspectors
Samsung!
12%
Android!
12%
Others!
4%
Windows Phone!
3%
Opera
5%
Safari iOS6
5%
Safari iOS7!
45%
Chrome!
14%

Measuring
DEMO

Proxies / Network sniffers
• Charles Proxy
• Fiddler
tools
Image from telerik fiddler

Connection simulators
• Charles Proxy
• Clumsy for Windows
• Network link conditioner from Xcode
• Net Limiter for Windows
• SlowyApp for Mac
tools

Navigation Timing API
• window.performance
• Timestamps available
html5 apis

navigation timing api
Samsung!
12%
Android!
12%
Others!
4%
Windows Phone!
3%
Opera
5%
Safari iOS6!
5%
Safari iOS7!
45%
Chrome!
14%

Navigation Timing API
html5 apis
DEMO

Resource Timing API
• Information per resource
html5 apis

resource timing api
Samsung!
12%
Android!
12%
Others!
4%
Windows Phone!
3%
Opera
5%
Safari iOS6!
5%
Safari iOS7!
45%
Chrome!
14%

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

Image from developers.google.com

What!!? Do you expect a page load
in 200ms?
(
)

No really, we just need the
PERCEPTION
of 1s

Redirects
• From 150 to 1000 ms per redirect
• mydomain.com -> m.mydomain.com
• URL shorteners

Redirections
DEMO

Redirections
• From 1 to 5s
!

idontwantyourfuckingapp.tumblr.com

Compress resources
• Use Gzip in HTTP
• For text-based files only

Basic browser behavior
• Network Fetch
• Parsing
• Rendering

Basic browser behavior
HTML
JS CSS

Basic browser behavior
HTML
JS CSS
BLOCKS PARSING BLOCKS RENDERING

The 14K limit

The 14K limit
• TCP slow start
• Initial congestion window: ~14.6Kb (compressed)
• > 14Kb will create another roundtrip

We need to separate
AVOBE THE FOLD
(ATF) content

ATF in 1s = 1 RTT ~ < 14Kb
ATF

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

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

Use illusion tricks
• Loading content animation
• Minimal-ui viewport ASAP (iOS 7.1+)
• Remember to keep the user engaged in 1s
ATF

Web Fonts
• Blocks text rendering
• Fonts are bigger than 14Kb
• Use them with care
• Remove characters
ATF

Responsive Web Design

Responsive Web Design
ATF on mobile is not the same as on desktop

RWD

RWD

RWD

RWD
not how it works by default

RWD

RWD

RWD

DON’T rely on
RESPONSIVE WEB DESIGN
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
• Use ATF experience:
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

JavaScript
framerate
• Avoid DOM manipulations inside loops/scroll
var e = document.querySelector("#test");
for (var i=0; i<100; i++) {
// change e attributes
});
JAVASCRIPT

CSS
framerate
• Promote GPU layers smartly
selector {
-webkit-transform: translateZ(0);
-webkit-perspective: 1000;
}
!
selector {
z-index: 10;
}
CSS

Animations
framerate
• Don’t animate from JavaScript for basic stuff
• Use requestAnimationFrame

remember 100ms immediate
feedback?

Immediate feedback
• The 300ms delay
!
• fixed viewport
• FastClick solution

Storage for immediate feedback
• web storage vs web sql vs indexeddb
• Finally IndexedDB on iOS 8!

navigator.geolocation
.getCurrentPosition(cbOK, cbKO,
{ maximumAge: 60000 });
JAVASCRIPT
Geolocation cache

Distract the user

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
• on iOS 8 new API (caution: on beta)

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!
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
firt.mobi/velocity

final thoughts
- measure and profile
- on real devices
- be simple, be aggressive

you can reach a good experience
Pictures)from)freedigitalphotos.net)
thank you!
twitter: @firt
mobilexweb.com
firt.mobi/pmw
Book signing:
Thu 10.45am