27 June 2010

Velocity 2010 was an excellent conference. Following are my takeways from the conference. There is tons more but following are some of the things that made a good impression and are likely not hard to do

Web performance optimization

Mobile performance optimization

Most of the recommendations have been taken off Maximiliano Firtman’s Mobile Web High Performance. You can view slides here.

  • Avoid JQuery unless you really need it. Check out slide 90. It takes 1.8 seconds on iPhone and 4 seconds on Android to download and parse JQuery. Use mobile optimized frameworks such as baseJS and XUI

  • Avoid DNS lookups and minimize number of requests since they are slow

  • Embed CSS and Javascript on the home page. After onload download external CSS and JS.

  • Use inline images (slide 56) and pictograms

  • Avoid redirects

  • Use native constructs especially for Webkit browsers e.g. -webkit-text-stroke

  • Keynote announced their Mobile Testing tool for desktops that looks promising http://mite.keynote.com/


  • According to Google SSL overhead these days is pretty minimal. Around 1% on today’s servers.

  • Pet peeve about the presentation is they were advising everyone to use less secure key lengths ie. 1024 bits and RC4 cipher to improve performance. It is true that adding SSL to insecure connections is certainly an improvement but it should be qualified. E-mail probably fine. Financial sites probably bad.


  • Hidden Scalability Gotchas in Memcached and Friends by Neil Gunther (author of Guerilla Capacity Planning) and Shanti Subramanyam discussed their findings around memcached. They used quantitative analysis to analyze different memcache versions. Based on their analysis using Neil’s model memcache 1.4.5 has higher contention than 1.2.8.