649666 - Do not create container layers for scrollboxes with (0, 0) scrollRange

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Benjamin Stover (:stechz)]

For remote builds, we are currently creating (empty) container layers for scroll frames that have a (0, 0) scroll range. I've noticed a lot of these in my testing, so we could cull many useless container layers.

Comment 1

[Benjamin Stover (:stechz)]

Attachment: Do not create container layers for scrollboxes with (0, 0) scrollRange

Comment 2

[Benjamin Stover (:stechz)]

Pushed http://hg.mozilla.org/mozilla-central/rev/a6467a88b056

Comment 3

[Benjamin Stover (:stechz)]

This may fix a Talos regression from 642246.

Comment 4

[JP Rosevear [:jpr]]

Before we can consider this, how big is the regression and is it definitely solved by this patch?

Comment 5

[Benjamin Stover (:stechz)]

We saw a Tp4 increase 9.69% on Nokia n900 mobile, but couldn't verify that this was a regression on Android devices. Mark said that an improvement occurred in a changeset range that included this bug and a cedar merge.

It's low risk patch, but then again, we're not very confident that there was a real Android regression or that this is the patch that fixed it.

Comment 6

[Johnny Stenback (:jst)]

Given the lack of obvious gain here we'll wait for 6 to get this. If there's a significant provable benefit here on a tier 1 platform then please renominate.