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Issue 643256 link

Starred by 2 users
Status: WontFix
Owner:
dmazz...@chromium.org
Closed: Aug 2017
Components:
EstimatedDays: ----
NextAction: ----
OS: All
Pri: 1
Type: Bug
Team-Accessibility



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Opening dev tools is slow when accessibility is enabled

Project Member Reported by ellyjo...@chromium.org, Sep 1 2016 
OS: 10.12 beta
Chrome: 55.0.2846.0 debug build

1) Open a tab and leave it at the new tab page
2) Enable VoiceOver (command-f5)
3) Open developer tools

The browser goes completely unresponsive for over a minute. *Eventually*, it finishes updating the dev tools pane, so it's not hung, just working very very slowly.

Comment 1 by ellyjo...@chromium.org, Sep 1 2016 

Some digging with Instruments:

The devtools helper process spends a great deal of time inside content::RenderAccessibilityImpl(), specifically in ui::AXTreeSerializer::SerializeChanges(). In a 1.2min run, sampled with Instruments, the helper spent 54 seconds inside ui::AXTreeSerializer::SerializeChanges().

Comment 2 by dmazz...@chromium.org, Sep 1 2016 

If a release build is a bit slower with VoiceOver on but still usable, then this is working as intended and probably not a recent regression.

Comment 3 by dmazz...@chromium.org, Sep 1 2016 

Also: SerializeChanges is expected if accessibility is slow; that's what triggers most of the work.

I'd be curious what the top function is once you get inside Blink - something in one of the AXObject subclasses, so the top function matching AXObject::, AXNodeObject::, or AXLayoutObject::

Comment 4 by pfeldman@chromium.org, Sep 1 2016

Owner: dmazz...@chromium.org
Status: Assigned (was: Untriaged)
We need to fix it, we are getting requests like this too often.

Comment 5 by aboxhall@chromium.org, Sep 1 2016 

Pavel, are you able to point to any other bugs filed about this to help diagnose?

Comment 8 by dmazz...@chromium.org, Nov 15 2016

Labels: -OS-Mac OS-All
Summary: Opening dev tools is slow when accessibility is enabled (was: VoiceOver: opening dev tools grinds browser to a halt)

Comment 9 by dmazz...@chromium.org, Mar 27 2017

Labels: NewComponent-Accessibility-Internals NewComponent-Accessibility

Comment 10 by dmazz...@chromium.org, Apr 21 2017

Components: Internals>Accessibility

Comment 11 by dmazz...@chromium.org, Apr 21 2017

Components: -UI>Accessibility
Labels: -newcomponent-accessibility-internals -newcomponent-accessibility

Comment 12 by dmazz...@chromium.org, Aug 10 2017

Status: WontFix (was: Assigned)
Closing this since we have other bugs tracking performance, and debug mode is not expected to be fast.
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