1758582 - The fancy apple product pages stutter heavily during scroll animation

Status: NEW

(Core :: Graphics: WebRender, defect)

Description

[Simonas Kazlauskas [:nagisa/:simukis]]

​​### Basic information

Steps to Reproduce:

1. Turn on resistFingerprinting to make Apple show the fancy product pages on Firefox.
2. Scroll around one of the pages for the new apple product announcements: https://www.apple.com/ipad-air/ https://www.apple.com/mac-studio/.

Expected Results:

Experience is a 60FPS butter.

Actual Results:

The scrolling is quite smooth during the first part of the profile where I'm scrolling through regular page. The framerate(?) tanks when scrolling through the page with the ipads animating in. The poor performance is particularly noticeable when large parts of the page are being animated at once. When smaller elements are being animated, the performance is more satisfactory.

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Performance recording (profile)

Profile URL:

https://share.firefox.dev/3Ks2Qs9. See in particular the screenshots.

System configuration:

OS version: NixOS
GPU model: Intel Cometlake (Gen9)
Number of cores: 8 logical
Amount of memory (RAM): plenty

More information

• Screenshot / screen recording: see profile screenshots
• Anonymized about:memory dump, for issues with memory usage: Not applicable
• Troubleshooting information: Go to about:support, click "Copy text to clipboard", paste it to a file, save it, and attach the file here.

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Thanks so much for your help.

Comment 1

[Simonas Kazlauskas [:nagisa/:simukis]]

A region of particular interest in the profile may be between the 5 seconds and 5.5second second mark where just 12 frames were produced, even though the profile doesn't demonstrate any particular resource shortage… Curious.

Comment 2

[Markus Stange [:mstange]]

The profile shows that the Renderer thread is blocked in mozilla::gl::GLContextEGL::SwapBuffers, which indicates that the resource shortage is on the GPU side.
So WebRender is creating too much work for the GPU on this page.

Comment 3

[Simonas Kazlauskas [:nagisa/:simukis]]

Aha, that could be the case. intel_gpu_top shows about about 90% utilization in Render/3D while scrolling around with the frequency being reported (1030~1090MHz) getting close to the maximum spec (1.1GHz) for the CPU in question.

Comment 4

[Gregory Pappas [:gregp]]

What do you mean by "fancy"? Apple.com is serving identical pages to Firefox Nightly and Chrome Dev (on my machine).

Comment 5

[Simonas Kazlauskas [:nagisa/:simukis]]

On my system, Apple delivers a page that animates elements during scrolling when resistFingerprinting is enabled (see reproduction steps and the screenshots in the profile) and a regular page without any animations when resistFingerprinting is disabled. It always delivers a page without any animations on Chromium for me.

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

How do I enable resistFingerprinting?
Do you mean privacy.resistFingerprinting pref?
(with or without the pref I get the same pages)

The animations do look very smooth on a Ryzen 5850U / Linux.

Moving this to gfx.

Comment 7

[Simonas Kazlauskas [:nagisa/:simukis]]

Yeah, I meant the privacy.resistFingerprinting about:config pref, sorry for not making it clearer initially.

Comment 8

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:bhood, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 9

[Bob Hood [:bhood]]

Glenn, let's start with WR here. Please tag somebody else if you feel it more appropriate.

Comment 10

[Bob Hood [:bhood]]

Can you attach your about:support output to this report, please?

Comment 11

[Glenn Watson [:gw]]

In addition to the about:support which we'll need, could you also please try enabling gfx.webrender.debug.gpu-time-queries and gfx.webrender.debug.profiler ? This will bring on an on-screen GPU profiler, some screenshots of what that looks like during the slow / heavy GPU part of the page might identify what the main bottleneck is here on your system.

Comment 12

[Simonas Kazlauskas [:nagisa/:simukis]]

Attachment: about:support

Comment 13

[Simonas Kazlauskas [:nagisa/:simukis]]

Attachment: Recording of the gfx profiler