Open Bug 854100 Opened 9 years ago Updated 3 years ago

Firefox is laggy when wiping the background on


(Core :: DOM: Core & HTML, defect, P5)

22 Branch





(Reporter: beta, Unassigned)


(Keywords: perf)


(1 file)

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:22.0) Gecko/20130322 Firefox/22.0
Build ID: 20130322031028

Steps to reproduce:

Visit the site for the reveal of Battlefield 4.
They have an interesting background which is a window above an image, the user swipes the cursor across the page to reveal whats behind, for the condensation to return after a time…
The animation isn’t as smooth as it could be, with Chromium 25 performing better.

Need to investigate if this is a Firefox issue or how they have coded the behaviour to prefer webkit/v8.
Keywords: perf
Attached file ‘minimal’ testcase
Site is closing soon, so keep a pared* down version as a test case.
Depends on jQuery from and two images on

*for whatever minimal is accepted, HTML is bare-bones, JS is scarily wasteful but likely a chunk of the perf issue.
Attachment #729623 - Attachment mime type: text/plain → text/html
Captured a profile of this lulls in graph is where I am pausing the mouse cursor for a few seconds to allow the swipe to fade and just to make the sampling clearer. Is this capturing useful info?
Mixed content blocking breaks this testcase... do you know if this is still an issue?
Flags: needinfo?(john)
On the most recent Nightly, yes, it still has jank. should have all the files to run locally
Flags: needinfo?(john)
Component: Untriaged → DOM
Product: Firefox → Core
I can't reproduce using 64-linux-nightly
Still there for me in Nightly 2013-08-26; Chrome still performs better in responsiveness and smoothness of drawing. Tried with OMTC about:config flags which improves the smoothness of animation and doesnt have the sudden pauses but latency is much worse - mouse cursor can be ahead by ~100 pixels

Adapter Description	NVIDIA Corporation -- GeForce GT 630/PCIe/SSE2
Device ID	GeForce GT 630/PCIe/SSE2
Driver Version	4.3.0 NVIDIA 325.08
GPU Accelerated Windows	0/1 Basic
windowLayerManagerRemote	false
AzureCanvasBackend	cairo
AzureContentBackend	none
AzureFallbackCanvasBackend	none
AzureSkiaAccelerated	0

Move all DOM bugs that haven’t been updated in more than 3 years and has no one currently assigned to P5.

If you have questions, please contact :mdaly.
Priority: -- → P5
Component: DOM → DOM: Core & HTML
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