Closed Bug 1282587 Opened 3 years ago Closed 3 years ago

Remove SCROLL_LINKED_EFFECT_FOUND telemetry probe (or extend the expiry)


(Core :: Panning and Zooming, defect, P3)

50 Branch



Tracking Status
firefox50 --- fixed


(Reporter: kats, Assigned: kats)


(Whiteboard: [gfx-noted])


(1 file)

Got this email:

The following histograms will be expiring on 2016-08-01, and should be removed from the codebase, or have their expiry versions updated:

* SCROLL_LINKED_EFFECT_FOUND expires in version 50.0a1 (watched by - Attempt to determine prevalence of scroll-linked effects on the web.

This is an automated message sent by Cerberus. See for details and source code.

I think we can probably remove this probe now, the number it's been reporting have been pretty stable and we don't need to keep it in the tree.
Attachment #8765623 - Flags: review?(botond) → review+
Pushed by
Remove telemetry probe expiring in Firefox 50. r=botond
Whiteboard: [gfx-noted]
Closed: 3 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla50

kats said:
> We had such telemetry, added in bug 1229052, and then subsequently removed in
> bug 1282587 because the number it had been reporting was pretty stable.

What were the numbers like?
And what was measured? :)
(sorry if I'm asking a dumb question, just want to better understand.)
Flags: needinfo?(bugmail)
It looks like telemetry.m.o doesn't show data for old probes. But the value was in the neighbourhood of 4% on desktop and 5% on mobile, if I recall correctly. I dug out the old email thread referenced at [1] and in that I claimed that  SCROLL_LINKED_EFFECT_FOUND was true for 4.2% of pages on beta 46.

Flags: needinfo?(bugmail)
Oh, and as to "what was measured" - for each top-level document the browser loaded, we recorded whether or not there was a change to certain CSS properties made by scroll event listeners. The CSS properties are the ones at [1]. This was used as an indication of whether or not the page was running JS to try and keep things visibly in-sync with the scroll position. It's not a perfect heuristic but I think good enough to be useful and representative.

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