1671498 - Slow/janky scroll on vanity fair article

Status: RESOLVED WORKSFORME

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

Description

[Asif Youssuff]

Basic information

Steps to Reproduce:

1. Visit https://www.vanityfair.com/style/2020/10/rudy-giulianis-daughter-on-voting-for-biden
2. Scroll down page

Expected Results:

Smooth scroll.

Actual Results:

Lots of judder.

---

More information

Profile URL: https://share.firefox.dev/317CnvF

Basic systems configuration:

OS version: Windows 10

GPU model: Intel(R) UHD Graphics 600

Number of cores: 2

Amount of memory (RAM): 8GB

Thanks so much for your help.

Comment 1

[Asif Youssuff]

Attachment: about:support

Comment 2

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

:yoasif, if you think that's a regression, then could you try to find a regression range in using for example mozregression?

Comment 3

[Markus Stange [:mstange]]

Slow composites on the renderer thread, and the profiler wasn't able to obtain a lot of samples from the GPU process. Raising the priority of the GPU process might help (bug 1671490). But I wonder why the discrepancy in the sampling rate between the parent process and the GPU process is so large. Is the priority of the GPU process currently lower than the priority of the parent process?

Comment 4

[Asif Youssuff]

Fresh profile after disabling some Windows services that helped lower my idle CPU use: https://share.firefox.dev/2KeX6bp

Comment 5

[Markus Stange [:mstange]]

Similar effect as before: The parent process is getting sampled consistently but the GPU process only has very sporadic samples.
Also, for some reason I don't see any "Composite" markers in the Renderer thread. That's weird.

Asif, could you get another profile where you sample fewer threads on the GPU process? Remove "RenderBackend,SceneBuilder,WrWorker" from the profiled thread list.

Also, the profile shows some input events getting delayed by D3D11DXVA2Manager code, and D3D11DXVA2Manager::Init runs at least 6 times.

Comment 6

[Asif Youssuff]

Markus, grabbed a new profile - removing RenderBackend,SceneBuilder,WrWorker

Take a look: https://share.firefox.dev/35Oa0p4

Comment 7

[Markus Stange [:mstange]]

Thanks, we're getting more samples now but still not a lot. I'm curious, does the profiler noticeably impact scrolling smoothness on this page? I'd also be curious in a profile with a much longer sampling interval, e.g. 100ms.

Comment 8

[Asif Youssuff]

I'm curious, does the profiler noticeably impact scrolling smoothness on this page?

Not really - maybe a tiny amount.

I'd also be curious in a profile with a much longer sampling interval, e.g. 100ms.

Here you go: https://share.firefox.dev/2UOQQsQ

Comment 9

[Markus Stange [:mstange]]

Thanks. Once we have the markers back (bug 1678698) we'll need to take a look at the duration and timing of the "Composite" markers on the renderer thread.

Comment 10

[Jean-Yves Avenard [:jya]]

(In reply to Markus Stange [:mstange] from comment #5)

Similar effect as before: The parent process is getting sampled consistently but the GPU process only has very sporadic samples.
Also, for some reason I don't see any "Composite" markers in the Renderer thread. That's weird.

Asif, could you get another profile where you sample fewer threads on the GPU process? Remove "RenderBackend,SceneBuilder,WrWorker" from the profiled thread list.

Also, the profile shows some input events getting delayed by D3D11DXVA2Manager code, and D3D11DXVA2Manager::Init runs at least 6 times.

D3D11DXVA2Manager::Init will only ever be called on either the RemoteDecoderManagerThread in the GPU/RDD process (to check if hardware decoder is available) or the "decoder" media threadpool (to do the actual creation of the decoder and the decoding)

It's never called on the main thread, regarding of the process.

It used to, not anymore.

Comment 11

[Markus Stange [:mstange]]

I've filed bug 1678684 on the D3D11DXVA2Manager issue. Jya, I'm moving your comment there.

Comment 12

[Glenn Watson [:gw]]

Seems very smooth now on a couple of machines I tested, not much going on in any of the WR profiler buckets.