Tuesday, August 2, 2011

Mobile Web Optimization Webinar Takeaway

Last week I attended a webinar from Compuware talking about mobile web optimization using page speed. The talk was very clear and well organized. It first went through the importance of mobile web performance, then discussed key difference between mobile and desktop, then detailed page speed rules about mobile web.

Browser is the entry point to mobile web
The browser is becoming the integration platform
The browser is becoming more complex
    - # of hosts per user transaction
    - Many RIA frameworks
    - Performance differences across devices

Free performance tools
Page Speed
dynaTrace Ajax Edition

Mobile web page load process
Mobile channel establishment
DNS lookup
TCP connect
Http request
Parse & Layout (subrequests)

Key differences between mobile and desktop
    round-trip time (High channel establishment time, lower RTT)
    bandwidth (3G vs Cable)
    CPU (JS execution times, layout times, 10x JS runtime cost, 1 ms per kb parsing)
    memory (more code/objects - more GC, more DOM, more memory)
Interaction model
    (touch vs click, mobile click event with 300-500ms delay)

Page Speed Rules
Use an application cache (how about localstorage?)
Defer JS parsing (how about deferring JS download?)
make landing page redirects cacheable (Cache-control: private, max-age > 0) (How long? 301 and 302 are both cacheable?)
prefer touch events (why not disable click event on mobile?)


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