Extension:NavigationTiming

The NavigationTiming extension allows logging perceived latency measurements, exposed by browsers as part of the W3C Navigation Timing spec, which "defines an interface for web applications to access timing information related to navigation and elements".

What data is logged?

 * See the EventLogging schema for NavigationTiming.
 * Browsers accounting for about 11% of Wikimedia traffic (as of April 2013) are not supported. See http://caniuse.com/nav-timing.

How is the information used?
Engineers at Wikimedia Foundation intend to use this data to assess the impact (positive and negative) of changes to code or server configuration, and thus to help guide ongoing work on site performance.

Additional resources

 * Navigation Timing API, specification from the W3C.
 * Annotated Timing object: simplified descriptions of the measurements.
 * Measuring Page Load Speed with Navigation Timing, HTML5 Rocks.
 * Wikimedia Performance: Data from Navigation Timing, performance.wikimedia.org.