925656 - [B2G][Browser] Content of webpage shows up slowly while swiping around the page.

Status: RESOLVED WONTFIX

(Core :: Graphics, defect)

Description

[Vincent Lin[:vilin]]

Attachment: IMG_2149.MOV

Steps to reproduce:

1. open browser,enter a website address and go
2. "after the webpage loaded", zooming the webpage
3. swiping around the page

Actual results:

The webpage shows up slowly and background color will be shown before the content.

Expected results:

The webpage will show up seamlessly.

Comment 1

[Vincent Lin[:vilin]]

Partner reported this issue on V1.1. We can also easily reproduce it on V1.2 or latest master, especially on high display resolution device. 

It seems the invisible part of webpage will be cleaned up and repainted again while becomes visible.

Looks like a performance issue on content rendering ? 

Is there any ongoing Bug related to this one ?

Comment 2

[Vincent Lin[:vilin]]

I found the latency is often too long(>10ms) here. It seams UI thread can't digest the task in time.
http://dxr.mozilla.org/mozilla-central/source/layout/ipc/RenderFrameParent.cpp#l498

Here are my locally-appended logging points.

10-14 05:37:28.272: I/Gecko(8846): APZC: Call GeckoContentController::RequestContentRepaint
@ http://dxr.mozilla.org/mozilla-central/source/gfx/layers/ipc/AsyncPanZoomController.cpp#l1022

10-14 05:37:28.272: I/Gecko(8846): APZC: Receive RequestContentRepaint@RemoteContentController then call DoRequestContentRepaint
@ http://dxr.mozilla.org/mozilla-central/source/layout/ipc/RenderFrameParent.cpp#l498

10-14 05:37:28.282: I/Gecko(8846): APZC: Receive DoRequestContentRepaint
@ http://dxr.mozilla.org/mozilla-central/source/layout/ipc/RenderFrameParent.cpp#l606

Comment 3

[Vincent Lin[:vilin]]

Attachment: Gecko profiler

Something wrong with dumped captured.sym.
Opening browser.sym is fine.

Comment 4

[Vincent Lin[:vilin]]

Attachment: Android profiler

It shows Browser's Paint() takes 1221.7 ms after receiving B2G's SendUpdateFrame() call here.

http://mxr.mozilla.org/mozilla-central/source/layout/ipc/RenderFrameParent.cpp#608

Paint() was dominated by DrawBufferWithRotation(), PlatformAllocSurfaceDescriptor() and DrawThebesLayer(). The root cause of this issue might be the same as Bug 920921.

Comment 5

[Benoit Girard (:BenWa)]

The APZC should be pre-rendering content outside the screen and make this less obvious. Kats would know the latest state of the APZC in the b2g browser.

Comment 6

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

From the video it looks like there is almost no displayport being used here. Is this reproducible on other pages too or just this one? It would help to get the checkerboard visualization tool up and running again to better see what's going on here and determine if the displayport heuristics need fixing.

Comment 7

[Sylvestre Ledru [:Sylvestre]]

Closing as we are not working on Firefox OS anymore.