1751471 - Consider adding a debug pref to turn off flexbox optimization

Status: RESOLVED FIXED

(Core :: Layout: Flexbox, task)

Description

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

I feel we often force the flex item's final reflow as a common trick when investigating flexbox sizing issues.

Daniel, do you feel it's worth landing your patch in bug 1747024 comment 9 permanently? An extra if in FlexItem::NeedsFinalReflow shouldn't impact the performance, and can also be useful to webcompat teams. If yes, I can work on a patch using StaticPref.

Comment 1

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

NI for comment 0.

Comment 2

[Daniel Holbert [:dholbert]]

Yes, that seems like a useful diagnostic tool. Thanks for volunteering to work on a patch to add it!

Name-wise, we should make sure it's not something that users would feel tempted to toggle if they go poking around about:config looking to do their own performance-tuning.

Comment 3

[Daniel Holbert [:dholbert]]

(In particular, my layout.css.flex.perf.cache-final-reflow.disabled naming in bug 1747024's diagnostic patch is a bit clunky.)

Maybe better: layout.css.flex.skip-final-reflow.enabled

(Or s/skip/optimize-away/ perhaps -- a bit longer, but a bit clearer about "true" being the good/default setting.)

Comment 4

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

Attachment: Bug 1751471 - Add a diagnostic preference to always run flex item's final reflow. r?dholbert

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d56556c22163
Add a diagnostic preference to always run flex item's final reflow. r=dholbert

Comment 6

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/d56556c22163