TICKEVENTS

Tick Events

When implementing a viewer one can use the tick events for performance tracking.

We use very short string names as tick labels, so the table below further describes these labels. Every start label has an assumed e_label for its "end" counterpart label. As an example if we executed perf.tick('label') we assume we have a counterpart perf.tick('e_label').

Name	id	Description
Install Styles	is	Set when the styles are installed.
End Install Styles	e_is	Set when the styles are done installing.
Window load event	ol	Window load event fired.
First viewport ready	pc	Fires when non-ad resources above the fold fired their load event measured from the time the user clicks (So takes pre-rendering into account)
Make Body Visible	mbv	Make Body Visible Executes.
On First Visible	ofv	The first time the page has been turned visible.
First paint time	fp	The time on the first non-blank paint of the page.
First contentful paint time	fcp	First paint with content. See https://github.com/WICG/paint-timing
First contentful paint (since visible)	fcpv	First paint with content, offset by first visible time
First input delay	fid	Millisecond delay in handling the first user input on the page. See https://github.com/WICG/event-timing
Cumulative Layout Shift	cls	The current maximum layout shift score with 5s windows and a 1s session gap. See https://web.dev/layout-instability-api
Cumulative Layout Shift Type Union	clstu	The bitwise union of all Element types that caused layout shift (see ELEMENT_TYPE_ENUM)
Cumulative Layout Shift, first exit	cls-1	The aggregate layout shift score when the user leaves the page (navigation, tab switching, dismissing application) for the first time.
Cumulative Layout Shift, second exit	cls-2	The aggregate layout shift score when the user leaves the page (navigation, tab switching, dismissing application) for the second time.
Largest Contentful Paint	lcp	The time in milliseconds for the largest contentful element to display.
Largest Contentful Paint Type	lcpt	The LCP target's Element type (see ELEMENT_TYPE_ENUM)
Largest Contentful Paint (since visible)	lcpv	The time in ms for largest contentful element to display, offset by first visible time. Based on render time, falls back to load time.
DOM Complete	domComplete	Time immediately before the browser sets the current document readiness of the current document to complete
DOM Content Loaded Event End	domContentLoadedEventEnd	Time immediately after the current document's DOMContentLoaded event completes
DOM Content Loaded Event Start	domContentLoadedEventStart	Time immediately before the user agent fires the DOMContentLoaded event at the current document
DOM Interactive	domInteractive	Time immediately before the user agent sets the current document readiness of the current document to interactive
Load Event End	loadEventEnd	Time when the load event of the current document is completed
Load Event Start	loadEventStart	Time immediately before the load event of the current document is fired
Request Start	requestStart	Time immediately before the user agent starts requesting the resource from the server
Response Start	responseStart	Time immediately after the user agent's HTTP parser receives the first byte of the response from the server