In the quest to improve user experience we need to collect some of the new user experience metrics. Collecting those metrics from our real users is the starting point for being able to improve them.
Today we collect these metrics in our synthetic tools but we miss them for real users.
The metrics we miss today is:
- Cumulative layout shift
- Largest contentful paint
- Long CPU tasks
- Interaction to next paint
There's also a couple of more things that we should do when we add new metrics:
- Move navigation timing metrics to the "new" https://wikitech.wikimedia.org/wiki/Event_Platform (so we follow the new pattern of collecting data)
- Make sure metrics are propagated to Prometheus so we can add better alerts on aggregated data (keeping track of p75/p95)