1421054 - MotionMark Animometer Multiply is spending 50% of BuildWebRenderCommands in RecurseAndDefineClip

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P1)

Description

[Markus Stange [:mstange]]

Profile: https://perfht.ml/2zJJO0C

Steps to reproduce:
 1. Go to http://browserbench.org/MotionMark/developer.html
 2. In the right column, check "Keep at a fixed complexity"
 3. In the left column, only check the Animometer: Multiply test, and set its complexity to 400
 4. Click "Run benchmark" and profile.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

https://searchfox.org/mozilla-central/rev/7a8c667bdd2a4a32746c9862356e199627c0896d/gfx/layers/wr/ScrollingLayersHelper.cpp#360-362

When I wrote this code the thing I had in mind to fix the potential cliff was what I described in bug 1415932, but that turned out to be harder than expected (see comment 1 on that bug). I can try again to see if I can come up with a better way.

Comment 2

[Kartikaya Gupta (email:[e-mail])]

I have an idea on how to fix this without going the route of bug 1415932. Picking this up as if it works it will be a big win.

Comment 3

[Kartikaya Gupta (email:[e-mail])]

I wasn't able to reproduce the problem as described in comment 0, however I did see RecurseAndDefineClip taking up 50% of time on MazeSolver as well, so I used that instead to test. The patch I have drastically improves MazeSolver time (~57 seconds down to ~14 seconds).

Try push to make sure it doesn't break anything: https://treeherder.mozilla.org/#/jobs?repo=try&revision=48ec1ceb1bc3aefaafc775ce080ab95efba32d49

Comment 4

[Kartikaya Gupta (email:[e-mail])]

For comparison the same build with WR disabled gives me results of ~17 seconds.

Comment 5

[Kartikaya Gupta (email:[e-mail])]

Attachment: Bug 1421054 - Remove performance cliff resulting from linear search through clips.

Review commit: https://reviewboard.mozilla.org/r/203652/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/203652/

Comment 6

[Markus Stange [:mstange]]

Comment on attachment 8932595 [details]
Bug 1421054 - Remove performance cliff resulting from linear search through clips.

https://reviewboard.mozilla.org/r/203652/#review209514

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/92847636d7b1
Remove performance cliff resulting from linear search through clips. r=mstange

Comment 8

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/92847636d7b1