1164601 - very jerky scrolling due to drawing background image slowly

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Timothy Nikkel (:tnikkel)]

Load http://redrockbiblecamp.com/cyclathon/
Increase the zoom (cmd-+).
Scroll.
Very jerky scrolling.
A profile says the time is spent drawing the page background image. The page background doesn't appear to be complicated in anyway.

Bisected to http://hg.mozilla.org/mozilla-central/rev/2d97da8feb72 using inbound builds.

Comment 1

[Mason Chang [Inactive] [:mchang]]

Is this on a mac?

I just tried adding create sampling restricted drawable back and it's still pretty janky on a retina display. It's not any jankier than without CSRD and deleting CSRD should be making background images a lot faster. It's also really slow on Firefox Dev Edition (Gecko 39). I don't think this is a regression from CSRD versus we just always paint background images slowly. 

I also tried scrolling with APZ and it checkerboards for a few seconds. I'll take a look at it, making background images paint faster is still good.

Comment 2

[Timothy Nikkel (:tnikkel)]

Yes on a mac. It's definitely a regression from http://hg.mozilla.org/mozilla-central/rev/2d97da8feb72 The difference is night and day for me. Like in the bad case we are talking almost unusable (not "it could be smoothly"). I'm not on a retina screen though. Firefox Dev, Beta and release are all fast for me.

Comment 3

[Timothy Nikkel (:tnikkel)]

(In reply to Timothy Nikkel (:tn) from comment #2)
> "it could be smoothly"

"it could be smoother"

Comment 4

[Timothy Nikkel (:tnikkel)]

And the profiler showed it was under nsDisplayCanvasBackgroundImage, indicating the root background specifically. The other background images were okay.

Comment 5

[Mason Chang [Inactive] [:mchang]]

(In reply to Timothy Nikkel (:tn) from comment #2)
> Yes on a mac. It's definitely a regression from
> http://hg.mozilla.org/mozilla-central/rev/2d97da8feb72 The difference is
> night and day for me. Like in the bad case we are talking almost unusable
> (not "it could be smoothly"). I'm not on a retina screen though. Firefox
> Dev, Beta and release are all fast for me.

Oh wow... hmm. I just tried on my external 27" monitor and it's usable, but not terrible. Both aren't smooth. What kind of external monitor do you have?

Comment 6

[Timothy Nikkel (:tnikkel)]

(In reply to Mason Chang [:mchang] from comment #5)
> Oh wow... hmm. I just tried on my external 27" monitor and it's usable, but
> not terrible. Both aren't smooth. What kind of external monitor do you have?

It's the same on my external monitor or on my laptop screen (neither is retina).

Comment 7

[Mason Chang [Inactive] [:mchang]]

@mstange: Can you please try the site http://redrockbiblecamp.com/cyclathon/ on your mac and see if it's significantly jankier on nightly versus dev, beta, or release edition? Thanks!

Comment 8

[Mason Chang [Inactive] [:mchang]]

So before with CSRD, we would have a giant image and paint that into one surface with CreateSamplingRestrictedDrawable, then draw each tile. with a portion of the surface. Now we have the image and create an image with a sampling rect and draw that. The performance of a repeated image will depend a lot on the tile size. I wonder if it's better to just create one giant surface, do the repeated image in one big swoop with a call to the native draw target and bypass tiling all together.

Comment 9

[u279076]

Does this bug still reproduce?

Comment 10

[Timothy Nikkel (:tnikkel)]

Tested on the original machine that I saw this, page scrolls fine now (with and without e10s).