1567889 - Improve will-change budget access during display list building

Status: RESOLVED FIXED

(Core :: Web Painting, enhancement, P3)

Description

[Miko Mynttinen]

The hashtable lookup for will-change budgeting was occasionally showing up in profiles, when investigating Youtube live chat performance (bug 1533815). We can avoid this by checking nsIFrame::MayHaveWillChangeBudget().
These patches showed a 1-2% improvement on DL mutate test on my MBP.

Comment 1

[Miko Mynttinen]

Attachment: Bug 1567889 - Part 1: Improve const correctness for some bool getters/setters r=mattwoodrow

Comment 2

[Miko Mynttinen]

Attachment: Bug 1567889 - Part 2: Avoid will-change budget lookups if the frame does not have the will-change bit set r=mattwoodrow

Depends on D38851

Comment 3

[Miko Mynttinen]

Attachment: Bug 1567889 - Part 3: Cleanup will change budgeting r=mattwoodrow

Depends on D38852

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

There are some r+ patches which didn't land and no activity in this bug for 2 weeks.
:miko, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 5

[Miko Mynttinen]

This patch is incomplete. When doing a full display list rebuild, we call nsDisplayListBuilder::ClearWillChangeBudget(), which does not clear the will-change flag from the frames. This can be solved by unconditionally clearing the flag, if we are doing a full display list build.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7534c2a4a2d1
Part 1: Improve const correctness for some bool getters/setters r=mattwoodrow
https://hg.mozilla.org/integration/autoland/rev/fe519c374527
Part 2: Avoid will-change budget lookups if the frame does not have the will-change bit set r=mattwoodrow
https://hg.mozilla.org/integration/autoland/rev/8ebcde6a7778
Part 3: Cleanup will change budgeting r=mattwoodrow

Comment 7

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/7534c2a4a2d1
https://hg.mozilla.org/mozilla-central/rev/fe519c374527
https://hg.mozilla.org/mozilla-central/rev/8ebcde6a7778