Deri Jones

Making your website fast - and scalable

Jan 14 2015 #Digibury@Digibury

@SciVisum_Ltd

Tue Feb 3rd

Website Speed

● Black Friday and Xmas peaks

The Need for Speed

● Impatience ● SEO

The Need for Speed

● Impatience ● SEO ● UX is the final USP

YourUX

Your offering

What makes sites slow ?

Network effects ●ADSL 3G 4G

Latency

Latency targets● Backbone best:

● Local: − ADSL 25 mS − Mobile 250 mS

Network effects ●Bulky: Images ●Too many objects ●Not using HTTP Keep alive

Firebug / devTools

Browser effects ●Objects block ●Rendering time

3rd party scripts

The offender: ●<script src="http://3rdparty.com/script.js"></script>

Old solution

These days<script async defer src="siteScript.js" onload="myInit()"></script>

These days:

Browser effects ●Objects block ●Rendering time ●3rd party blocking

Ad serving is slowAnd no political motive to be faster Will get slower as big-Data progresses

Responsive webAvoid the Whitehouse.org story...

Can be good: ●Painless install ●Many configuration choices

Can be tricky: ●Embedded CSS obsession

Tools

● Firebug, DevTools ● HTTPArchive.org ● Webpagetest.org

Designers vs Speeders

Challenges

● Responsive web: − Better than 2 sites www. and m.

Website Scaling

Surprising lessons

● Cloud auto-scaling – doesn't work

Surprising lessons

Cloud auto-scaling – doesn't work − Scales too late − Allows rest of farm to die − Small print: − Strictly 'very often' doesn't work

Surpising lessons

● Cloud auto-scaling – doesn't work − Scales too late − Allows rest of farm to die

● Cloud auto-scaling

● Uncertain spin-up time ● DOA

● Scaling

● Don't obsess Disk IO − Yes it's moving metal − Web is a lot about static content

● Scaling

● The code platforms are good ● Many problems in SysAdmin configs ● CDNs

− Cache-Miss hurts

● But don't assume!

● Scaling

● Many big hosters: − Not motivated to help you

● Scaling

Users' Experience

It's both: ●The new battleground ●A challenge

− Single Page website − Offline-cache content − Users' journeys complexity

User Experience

● Cultural shift − Make every one responsible for it!

● Performance is a deliverable − Test every release − Continuous Integration

User Experience

● Hard ● Easier to save timings in your code

− ElasticSearch, Graphite ● RUM and Analytics help

User Experience

● 'Do what your Customers do' − more Synthetic monitoring − For another day ...

Making your website fast - and scalable

Deri Jones

Digibury January 2015

Resources● London Web performance meetup

− http://www.meetup.com/London-Web-Performance-Group

● Third Party Footprints

− http://www.slideshare.net/bbinto/third-party-footprint-evaluating-the-performance-of-external-scripts

● HTTP Archive

− https://speakerdeck.com/deanohume/the-good-the-bad-and-the-ugly-of-the-http-archive