Closed
Bug 1128342
Opened 9 years ago
Closed 5 years ago
Scrolling on http://2015.jsconf.eu/ is not smooth
Categories
(Core :: Graphics, defect)
Tracking
()
RESOLVED
WORKSFORME
People
(Reporter: julian.viereck, Unassigned)
References
Details
(Whiteboard: [gfx-noted])
Using the latest Nightly build and Firefox 35 release channel, there is a drop in the frame rate from 73 to temporary 5 frames on my MacBook 15" when scrolling down the page on http://2015.jsconf.eu/. (I measured the frame rate using the DevTools profiler.) Scrolling the same page on Google Chrome yields smooth scrolling behavior. As the results show up on Firefox 35 as well, I guess this is not related to e10s.
Comment 1•9 years ago
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Platform performance profile: http://people.mozilla.org/~bgirard/cleopatra_staging/#report=496b8c07f65516ce0ddaa8fdfefec6efe5ccc716&filter=[{"type"%3A"RangeSampleFilter","start"%3A976,"end"%3A1811}]&selection=0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,234,235,236,237,238,239,240,241,242,243,116,117,133,134,135,136,137,138,139,140,339,808,809,810,810,811,1106,1107,1108,1110,170,171,1408,173,696,186,187,188,697,698,699,700,701,702,703,1112,704,705,706 I'd guess we're making a large layer tree mutation during the scroll will cause us to rebuild a large layer container a gradient. Ideally better gradient performance would help but better layer heuristics would help too. The page could simplify the gradient if you know the author.
Comment 2•9 years ago
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CSS line responsible for the slow down: background-image:linear-gradient(to left, rgba(0,0,0,0),rgba(0,0,0,0) calc((.75 * 1280px) + ((100% - 1280px)/2)),#e10079 calc((.75 * 1280px) + ((100% - 1280px)/2)),#e10079 100%) This is a linear-gradient so I'm not sure why it's that slow to paint. Jeff?
Flags: needinfo?(jmuizelaar)
Comment 3•9 years ago
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Maybe there's a colorspace mismatch. The CoreGraphics symbols in the profile don't make a lot of sense...
Flags: needinfo?(jmuizelaar)
Comment 4•9 years ago
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Yeah, the CoreGraphics symbols in that profile look wrong. I get something saner from Instruments. Anyways, perhaps Chrome is hiding the problem better with async scrolling? The page is sort of dumb for using a linear gradient to get a solid color bar... but I guess it's easy to allow the size of the gradient to change then...
Comment 5•9 years ago
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bug 913443 would get us to avoid the paint when making the transition which is another way to make this fast.
Blocks: 913443
Updated•9 years ago
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Whiteboard: [gfx-noted]
Comment 6•5 years ago
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This is pretty smooth now with APZ and all.
Status: NEW → RESOLVED
Closed: 5 years ago
Resolution: --- → WORKSFORME
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Description
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