Philip Tellis on performance: a developer evening in London, England

Last week around 50 people in London, England came out to hear Philip Tellis of Yahoo! talk about website performance and how to measure it.

performance-evening by  you.

Instead of going through the hopefully by now well-known 34 rules of Web performance that you can apply to your sites — and automatically check with YSlow which ones need your attention — Philip took a different stance on Web performance testing.

Specifically he mentioned the following points:

  • Myths about bandwidth and latency, and which one is more important
  • Why your modem can actually be a bottleneck
  • A comparison of different ISPs when it comes to latency (in the US and the UK)
  • Why doubling your bandwidth does not make everything twice as fast
  • Why it can make more sense to fly a 737 instead of the larger and faster 747
  • How to measure your user's bandwidth and latency
  • How to optimize your sites to work around latency issues

Philip's slides are available on SlideShare:

The audio of the talk, sadly enough, is too loud — we fixed it as best we could — so make sure you turn down the volume before you listen to it. The talk is available as a 29MB MP3 and also as OGG at

After an interesting Q&A session and a few beers, we hope that everybody went home with some new ideas on how to make the Web a faster place for us all.

Christian Heilmann
Christian Heilmann (@codepo8)
Yahoo! Senior Developer Evangelist