Performance

Performance Q & A

Is Cockpit slow?

Yes.

Some parts of Cockpit are especially slow, such as logs, services, storage, etc.

Is Cockpit being slow a problem for end users?

Yes, it was mentioned several different times in various usability studies.

Some of the speed issues are due to Cockpit providing no feedback that things will take a while, others are because Cockpit takes a very long time to actually load a page or perform a task.

Most of the speed issues are related to page load times.

How important is it to address Cockpit's slowness?

It's important, but be can do it in tandem with other work.

Sometimes being consious during development is enough. For existing pages, we'll need to retrofit them with various techniquest to improve speed (both actual and percieved).

What can we do?

Improve feeling of speed, including:

Progress indicators
Progressive loading (page structure loads in, with placeholders; actual data is swapped in)
Ensure all fonts are loaded on page load (instead of pulled in when needed), to prevent text flashing
Add transitions and animations

Improve actual performance

Identify and fix bottlenecks
Try to load & display data async instead of sync
Split data retrieval into chunks
Cache and pre-cache (start loading services, logs, network card info, storage info, packages that need updating, etc. directly after the overview page loads)
Don't duplicate CSS & JavaScript per page — have a base library that's re-used, but not recompiled into everything
Limit # of assets to load (bundle when possible) — this should be balanced with the above
Move per-page custom widgets upstream to Cockpit, where they can be shared (JS, HTML, CSS)

Measure

Including page load performance in tests
Compare metrics to previous metrics on the same hardware (relative gains / losses)
Test on a "typical" system and ensure various thresholds are met
Set targets for number of assets, file size (HTML, JS, CSS, compelte), speed until first paint, speed until page is completely loaded