Velocity Web Operations and Performance Day 1


I’ve just finished up a highly enjoyable first day here at the Velocity Conference in New York. Day 1 consisted of a full day of tutorials before the main conference tracks kick off on Tuesday and Wednesday.

It was a great opportunity to touch base with many of our peers and partners such as Cedexis, Dyn, EdgeCast, MaxCDN and Fastly. Being a web performance focused company, my eyes were firmly on the Performance Track. Here is what I saw:

Everything You Wanted To Know About Web Performance (but were afraid to ask)

Some great tidbits from this talk:

  • Ghostery is an awesome add-on that shows 3rd party scripts that might be slowing your site down
  • As if 3rd party scripts aren’t challenging enough, now there are 4th party scripts!
  • Its well known that ad networks can affect performance, but the magnitude of the difference can vary for different users on same site (due to ad personalisation)
  • Spof-o-matic is another nifty tool that lets you measure and isolate 3rd party script performance
  • What is old is new again – iframes are back in fashion, as they load content in an asynchronous fashion
  • Consider a 3rd party SLA for your scripts e.g. allow an Ad 500ms to load and render or we skip it for a given page load.

WebPageTest – Private Instances

Some great tidbits from this talk:

  • Don’t use webpagetest public instances as monitoring service. It’s focused on ad-hoc tests. Deploy your own private instances for that!
  • Patrick hopes that someone makes a commercial monitoring service on top of their own (private) test agents. Get to work folks!
  • There is now experimental support for recurring benchmarks on private instances. Try it out yourself.

Beyond Page Level Metrics

Some great tidbits from this talk:

  • Focused on next gen RUM – what don’t we get from current navigation timing APIs?
  • How do you get rum/timing from end users?
  • Different browser / device have caps on maximum simultaneous hostnames and connections
  • “Timing-Allow-Origin *” header allows browser to check timing of external resources (e.g. CDN hosted) as well as internal
  • Timing APIs can be effective in finding 3rd party Single Points of Failure (SPOFs)
  • Correlating RUM to conversions is the holy grail
  • Tolerance to load time varies by country – Australians and Canadians are more patient despite overall slower load times. Americans are less tolerant (more impatient) despite overall faster loads, and are often where the most benefit can be achieved from optimisation efforts

W3C Web Performance APIs in Practice – Alois Reitbauer (

No slides – but better yet a GitHub repo with runnable examples.

  • New W3 Error Logging API is in the works
  • For now, you can find missing assets that are in the DOM but not the timing object
  • Mark “above the fold” in your page/dom for additional timing insights
  • Beacon API is in the works to deliver browser instrumented data
  • Available now in Firefox and chrome canary
  • Possibilities exist to integrate these APIs into Selenium tests to integrate into your CI workflow
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