Bug 102585 – Performance degradation while rendering MathML content, freezes the tab.

• Status: RESOLVED
• Resolution: FIXED
• Component: MathML

[A George]

Created attachment 174814 [details]
Test Page 1

There is a performance degradation on latest Chrome Canary builds and Webkit Nightly builds(WebKit-r131444) while rendering MathML content.
Verified on older nightly builds and found that after change set r128837 (Mathml to use flexboxes) the issue is seen.

 Findings below

 WebKit-r128813: Test page 1 & 2 works well on WinLauncher and Webkit.exe

 WebKit-r128857/WebKit-r131444: Test page 1 - Renders after a perceivable  delay in WinLauncher and Webkit.exe
                                Test page 2 - Both Winlauncher & Webkit.exe freezes/hangs

 Chrome Canary Version 25.0.1326.0 canary: Test page 1 - Renders after a perceivable  delay.
                                          Test page 2 - Application freezes/hangs and after sometime shows 'Page unresponsive' pop-up.

[A George]

Created attachment 174815 [details]
Test Page 2

[Tony Chang]

This is because an auto sized column flexbox requires 2 layouts.  If you nest them, this creates 2^n layouts.

Bug 102352 should fix this issue.

[Carlos Garcia Campos]

Yes, I confirm both test cases render fast with patch attached to bug #102352

[Tony Chang]

Created attachment 177291 [details]
Patch

[WebKit Review Bot]

Comment on attachment 177291 [details]
Patch

Rejecting attachment 177291 [details] from commit-queue.

Failed to run "['/mnt/git/webkit-commit-queue/Tools/Scripts/webkit-patch', '--status-host=queues.webkit.org', '-..." exit_code: 2

Last 500 characters of output:
it line 152.

Failed to run "['Tools/Scripts/update-webkit', '--chromium', '--force-update']" exit_code: 2
Updating OpenSource
From http://git.chromium.org/external/Webkit
 + 1bf3e3e...e4b679b HEAD       -> origin/HEAD  (forced update)
error: Ref refs/remotes/origin/master is at e4b679b9687bbd8bc190703dbf1027d8a33fdfb6 but expected 1bf3e3e6422a99acd8c135b162e171c31481e2dd
 ! 1bf3e3e...e4b679b master     -> origin/master  (unable to update local ref)
Died at Tools/Scripts/update-webkit line 152.

Full output: http://queues.webkit.org/results/15117481

[WebKit Review Bot]

Comment on attachment 177291 [details]
Patch

Clearing flags on attachment: 177291

Committed r136428: <http://trac.webkit.org/changeset/136428>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.