1540587 - After a playback of AV1 video, RDD isn't used for video in tabs in other content processes

Status: VERIFIED FIXED

(Core :: Audio/Video: Playback, defect, P1)

Description

[tgn-ff]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

1. Open Firefox with a clean profile.
2. Play an AV1 video in a tab.
3. Open a second tab and ensure that it's in a different content process, then load to play the same or another video.
4. Observe the CPU usage and the number of threads of RDD through a system monitor at steps (2) and (3).

Actual results:

At step (2), normally, there's some CPU usage for the RDD process, and 11 threads are counted. At step (3) there's no CPU usage at all, and 6 threads are counted.

Expected results:

Similar results at both steps.

It's a regression. Bisection points to Bug 1539030.

23:09.01 INFO: No more inbound revisions, bisection finished.
23:09.01 INFO: Last good revision: 105411e3cf06b2fca98d4e0507efb80875103228
23:09.01 INFO: First bad revision: a0bed49e8b107a7dc6f1f74dcddd5353ae177130
23:09.01 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=105411e3cf06b2fca98d4e0507efb80875103228&tochange=a0bed49e8b107a7dc6f1f74dcddd5353ae177130

Comment 1

[Michael Froman [:mjf]]

I'll take a look.

Comment 2

[Michael Froman [:mjf]]

Yep - I missed that. Thank you for catching this!

Comment 3

[Michael Froman [:mjf]]

Attachment: Bug 1540587 - remove patch for 1539030 to fix decoding on additional tabs. r?jya!

The patch for 1539030 didn't do what I'd hoped, and caused issues
with decoding av1 on additional tabs so I'm removing the "fix".

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a8474c6fd9a3
remove patch for 1539030 to fix decoding on additional tabs. r=jya

Comment 5

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/a8474c6fd9a3

Comment 6

[Alexandru Trif, Desktop QA [:atrif]]

Hello!
I successfully reproduced the issue using Firefox 68.0a1 (20190331215222) using Ubuntu 18.0.4 when playing an AV1 video just having 13 threads for RDD process after Step2 and no CPU usage at all and 6 threads counted after Step3 from comment 0.

Can I get a confirmation that the present behavior in the following video is the expected one? Made a screen recording with the results using Firefox 68.0 (20190705220548): link.

Thank you!

Comment 7

[Michael Froman [:mjf]]

:atrif, would you mind describing the current behavior you're asking to verify in the video? Thanks!

Comment 8

[Alexandru Trif, Desktop QA [:atrif]]

Yes ofc, sorry for not doing that in the first place. Using the same STR as in comment 0 to compare the results:

(In reply to tgn-ff from comment #0)

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

1. Open Firefox with a clean profile.
2. Play an AV1 video in a tab.
3. Open a second tab and ensure that it's in a different content process, then load to play the same or another video.
4. Observe the CPU usage and the number of threads of RDD through a system monitor at steps (2) and (3).

Actual results:

At step (2), normally, there's some CPU usage for the RDD process, and 11 threads are counted. At step (3) there's no CPU usage at all, and 6 threads are counted.

Expected results:

Similar results at both steps.

After step 2 the thread count for the RDD process is set to 11 and uses some CPU.

After step 3 the thread count remains the same and the RDD process is still using almost the same amount of CPU.

Changing video tabs between them increase the thread count and CPU usage but after waiting for a while it comes back to normal.
If there more information needed please let me know. Thank you!

Comment 9

[Michael Froman [:mjf]]

That all sounds like I'd expect.

Comment 10

[Alexandru Trif, Desktop QA [:atrif]]

Thank you!
As per comment 8 and comment 9, the issue is verified fixed using Firefox 68.0 (20190705220548) on Ubuntu 18.04.