Note: There are a few cases of duplicates in user autocompletion which are being worked on.

Large (1000x1000px) SVG backgrounds are extremely slow to scroll




6 years ago
3 years ago


(Reporter: atul, Unassigned)



Firefox Tracking Flags

(Not tracked)




(2 attachments)



6 years ago
Created attachment 569727 [details]
Simple HTML page with DIVs that contain SVGs as backgrounds

The following attachment doesn't phase Mobile Safari on an iPhone 4, yet it brings my Macbook Air to a crawl when viewed using the latest Firefox Nightly.

Comment 1

6 years ago
Hmm.  Seems to work OK here, but on an mbp, not an air.

Would you be willing to use a shark nightly and generate a sample?
(Works fine for me on my Linux desktop, too, but it's got a good bit more power than the Air.)

Comment 3

6 years ago
No problem on Windows either.

Comment 4

6 years ago
Sure, where can I get a shark nightly and how do I generate a sample?

Comment 5

6 years ago
Oh, I should also mention that just having the page open doesn't slow down my air--it's specifically the act of scrolling w/ a mousewheel that causes lots of stuttering and such. (Most pages scroll just fine with the mouse wheel.)
Yup, I figured that from the bug title -- I was referring to mousewheel scrolling in comment 2.  FWIW, my firefox CPU usage doesn't go over ~20% while I'm scrolling.  (This is true even if I enable the 'general.smoothScroll' pref - still nice and smooth & CPU usage doesn't go over around 20%)

Comment 7

6 years ago
You can get the latest shark nightly at

As far as generating a sample, the simplest thing to do is to open Activity Monitor, select Nightly in the list, click the "Sample Process" button, and in the next several seconds do a bunch of scrolling over in the Firefox window.  Once the sample has been generated, copy and paste it into a text file and attach the file here.
Keywords: perf
Hmm, the attachment doesn't work anymore because the:

  <base href="">

isn't being used when resolving the path for the:

  <link rel="stylesheet" href="floors.css">

Was that an intentional change at some point?

Comment 9

4 years ago
The <base> is in fact being used.  It's just that non-https subresource loads from an https page (like the bugzilla attachment page) are blocked by default in current nightlies.  You can unblock it for one load by clicking the little near-invisible shield icon to the left of the lock icon in your url bar and selecting "Disable Protection on This Page" from the dropdown.
Created attachment 754166 [details]
zip of live example
For what it's worth paint-flashing isn't showing any invalidation issues.

Maybe bug 764299 will make the scrolling a bit smoother.
Depends on: 764299
Atul, since you were the only person who experienced this, can you retest this using latest Nightly, both with with image.mem.surfacecache.max_size_kb set to its default value, and with it set to zero. (To help distinguish between whether bug 764299 helped or not.)
Flags: needinfo?(avarma)
Atul, if you still experience this please do reopen.
Last Resolved: 3 years ago
Flags: needinfo?(avarma)
Resolution: --- → INCOMPLETE
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