LiveBlog: PageSpeed
Bryan McQuade (Google), Richard Rabbat (Google, Inc.)
What’s Page Speed
- FF/Firebug addon
- http://code.google.com/p/page-speed
- Optimizes images, minifies JS, tells you what you should defer
- 100K downloads in 10 days, 1000s of tweets, 100s of blog postings
How’d it start
- wanted to help stop relearning lessons in new apps
- keep you from unintended consequeces (e.g. vary header, squid won’t cache anything with params, etc.) Google map tiles used to have ? in URL; removing it gave huge boost in perf, huge reduction in requests
- Sourced from many smart people on the web
Prioritizes according to importance/savings, gives easy way to see detailed info about any given rule, what’s violating it, docs on why and how of each rule
Defer loading JS as much as possible
- Rule looks to see what’s not been invoked before OnLoad completes
- Not enabled by default, has perf hit
- Load multiple times in multiple scenarios; some JS is triggered in different
Inefficient CSS Selectors: based on David Hyatt’s post on inefficient selectors
Activity Panel
- Show where most time is spent, where you should focus optimization
- Shows DNS, network, connection, latency, data available for use, JS parse/exec, cache hits
- Coming: paint events, screen snapshotting
BBC “has lots of room for optimization” gmail waterfall is hugely vertical!
Just released FF3.5 compatible version
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Published
23 June 2009