Being Mark Cohen

Speed Matters – by @markstanto

Things to come back to and probably search for later

Some of the concepts to be aware of:

• Empty cache / primed cache
• Refresh / revisit
• Page ready / page complete
• Throughput / Latency

Latency – overhead costs in round trip to server, besides actual data change

Profiling page loads with firebug
Interesting change – css stays up top, js goes as far down the page as possible.

Cache Controls
- ETags (Entity tags)
- Apache / IIS support. (server config)

Server will say “not modified, us cached”
Only good for single-server

Expires tag: specific date (or timespan?)

Apache config:

• ExpiresActive on
• ExpiresDefault 365
• outputfilterByType DEFLATE text/html text/css application/javascript <– case study 96KB reduction

Big No’s
pragma:”no-cache”
cache-control: set to zero

Minify JS

• YIU ccompressor – 24 KB reduction on case study site, usually more.
• Dojo Shrinksafe
• YUI – calls itself safe, usually low-risk. but always test
• Packer – most aggressive, most risky

- need to test all.

CompressorRater – tells you the savings using different algorithms
- use to choose best tool

GZip – only text files, not images

Split Components across Domains
- IE only 2 components at a time
- More than 3 aliases, DNS overhead counters benefit (we have much more than this)
Sprites
- composite images, use css to position

Restructure Content
- Delay loading of less imprtant stuff to later

Eg: Logo in css, images inline. logo shows after images.

Javascript rotator to lazy-load images (we should do this)

Recap

• optimise images
• combined js
• combined css
• js to bottom
• cache control:expires
• minify
• gzip
• split domains (CDN)

Tools

• CacheStatus
• PageSpeed
• Firebug
• LiveHTTPHeaders
• CharlesProxy

http://stevesouders.com
http://developers.yahoo.com/performance/

Roll-up:

• Low hanging fruit
• incremental improvements
• Incorporate into your process – ie in Ant, include in deployment process.
• http://delicious.com/markstanton/speed-talk