1383444 - 3.01ms uninterruptible reflow at nextStep@chrome://global/content/bindings/progressmeter.xml:83:19

Status: RESOLVED INVALID

(Toolkit :: UI Widgets, defect, P4)

Description

[Kris Maglione [:kmag]]

Here's the stack:

nextStep@chrome://global/content/bindings/progressmeter.xml:83:19
FrameRequestCallback*nextStep@chrome://global/content/bindings/progressmeter.xml:105:15
FrameRequestCallback*nextStep@chrome://global/content/bindings/progressmeter.xml:105:15
FrameRequestCallback*_init@chrome://global/content/bindings/progressmeter.xml:109:11
progressmeter-undetermined_XBL_Constructor@chrome://global/content/bindings/progressmeter.xml:113:1
PopupNotifications_showPanel@resource://gre/modules/PopupNotifications.jsm:932:9
PopupNotifications_update@resource://gre/modules/PopupNotifications.jsm:1097:9
_onButtonEvent@resource://gre/modules/PopupNotifications.jsm:1480:5
oncommand@chrome://browser/content/browser.xul:1:1

Comment 1

[Daniel Holbert [:dholbert]]

The layout flush comes from the call to "stack.boxObject.width" here:
https://dxr.mozilla.org/mozilla-central/rev/7d2e89fb92331d7e4296391213c1e63db628e046/toolkit/content/widgets/progressmeter.xml#82

...in the progressmeter-undetermined "_init" method.

That .width accessor does indeed flush layout (unsurprisingly), via a call from BoxObject::Width() to BoxObject::GetOffsetRect() to BoxObject::GetFrame(), which calls GetPresShell() with aFlushLayout==true:
https://dxr.mozilla.org/mozilla-central/rev/7d2e89fb92331d7e4296391213c1e63db628e046/layout/xul/BoxObject.cpp#110

Comment 2

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #1)
> The layout flush comes from the call to "stack.boxObject.width" here:
[...]
> ...in the progressmeter-undetermined "_init" method.

Sorry, I meant it's in the <method name="_init"> tag -- but really the flush happens every refresh driver tick (!) via  a requestAnimationFrame callback called "nextStep"

Comment 3

[Florian Quèze [:florian]]

(In reply to Daniel Holbert [:dholbert] from comment #2)
> the flush happens every refresh driver tick (!) via  a requestAnimationFrame callback
> called "nextStep"

Ugh :-(.

But this binding seems to only be referenced on Linux: http://searchfox.org/mozilla-central/search?q=progressmeter-undetermined

Comment 4

[Kris Maglione [:kmag]]

(In reply to Florian Quèze [:florian] [:flo] (away until August 7th) from comment #3)
> (In reply to Daniel Holbert [:dholbert] from comment #2)
> > the flush happens every refresh driver tick (!) via  a requestAnimationFrame callback
> > called "nextStep"
> 
> Ugh :-(.

Yeah, that seemed particularly terrible to me, too...

> But this binding seems to only be referenced on Linux:
> http://searchfox.org/mozilla-central/search?q=progressmeter-undetermined

Huh. Interesting. I wonder why that is...

Comment 5

[Kris Maglione [:kmag]]

Apparently bug 658829 switched to native progress meters on other platforms.

Comment 6

[Florian Quèze [:florian]]

fxperf:p3 because Linux-only, I would have made it a p2 if other platforms were affected.

Comment 7

[Gregory Pappas [:gregp]]

I think it's safe to close this bug because the progressmeter element was removed in bug 1499947.