1633864 - Refreshdriver took 4.6 seconds to tick when doing 2d canvas text rendering

Status: NEW

(Core :: Graphics: Canvas2D, defect, P3)

Description

[Sean Feng [:sefeng211]]

The issue was originally reported in bug 1313675.
Here's the profile. https://bit.ly/2yb4aQP

What was happening here was that when the content of danmaku was light, Firefox played them well, and started to be sluggish when the content was heavy as it started to take longer to paint.

I tried to play the same video in Chrome and it worked well.

Based on the profile, during this 4.6 seconds, most of the time consumed by Gfx. 52% from mozilla::gfx::AlphaBoxBlur::BoxBlur_SSE2, 15% was convert_to_alpha8 and 11% was ssse3::blit_mask_d32_a8.

I think these functions are good starting points to fix the problem.

Comment 1

[Timothy Nikkel (:tnikkel)]

Is this because Chrome uses accelerated canvas and we don't?

Comment 2

[Kelsey Gilbert [:jgilbert]]

Yes.

Comment 3

[Sean Feng [:sefeng211]]

Are there some directions/guesses/hypothesis about this bug that can be brought up to move this bug forward?

I'd like to spend some time on this if possible. Thanks!

Comment 4

[Timothy Nikkel (:tnikkel)]

I think the idea is that if performance is important (ie they want acceleration) than authors should be using webgl instead of canvas 2d. But don't quote me on that.

Comment 5

[Sean Feng [:sefeng211]]

hmm...okay..I'd guess there are still rooms for improvements?

Bas seems to know the blurring code well. Bas, would you be able to see some potential improvements we can make?

Comment 6

[Bas Schouten (:bas.schouten)]

(In reply to Sean Feng [:sefeng] from comment #5)

hmm...okay..I'd guess there are still rooms for improvements?

Bas seems to know the blurring code well. Bas, would you be able to see some potential improvements we can make?

I think we should accelerate this :P. But aiui tn that's not what we want, so I guess we just get to be slow. :)

Comment 7

[Timothy Nikkel (:tnikkel)]

I'm just repeating what I think I heard in an effort to try to help this bug, it's not my proclamation. So if I've got something wrong I apologize.