1156266 - Consider adding a mode to about:performance where it only updates upon jank

Status: RESOLVED WONTFIX

(Toolkit :: Performance Monitoring, defect)

Description

[Emanuel Hoogeveen [:ehoogeveen]]

about:performance currently updates periodically with a 10 second interval (after bug 1153877). However, users are unlikely to look at it unless they are experiencing jank, so it would be nice if it updated after such an event - so that when users go to look, it contains the information they're expecting.

I don't know much about how about:performance works - when it updates, does it show the average usage over the most recent interval? If so, a jank update would have to do something similar (rather than averaging everything since the last update). Perhaps it could even show a more dynamic interval based on the length of the jank.

One question is whether this would need to be configurable. For instance, would users only care about the maximum level of jank seen so far? In that case, we could track the maximum and only update when it is exceeded. But this has the problem that the maximum may happen, say, during browser startup, and may not be at all relevant to the jank the user wants to know about. In that case we'd have to offer a way to clear the maximum, or throw it away automatically after a while.

Alternatively, we could leave the desired minimum jank level for an update up to the user. This might be a bit difficult for a user to divine (start at level 10, and go down until the jank shows up?), though to be helpful perhaps we could set it to the maximum jank level seen up to that point (although that gets into the same difficulty as above).

In any case, just opening this bug to have the idea tracked. Clearly it needs some work fleshing out the details :)

Comment 1

[David Teller [:Yoric] - still alive but not very active]

Note that the latest versions of about:performance have something kind-of-vaguely-like-that.

Comment 2

[Florian Quèze [:florian]]

about:performance is being redesigned; mass closing the bugs related to parts of the current about:performance page that we are not keeping.

Our goals with the redesign are to reduce the overhead caused by having the page opened, increase the reliability of the displayed information, and make the offered information actionable for most users. The back-end work is being tracked in bug 1419681.