1538195 - AV1 playback uses significantly more CPU when RDD is enabled

Status: RESOLVED DUPLICATE of bug 1538474

(Core :: Audio/Video: Playback, defect, P2)

Description

[tgn-ff]

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

Steps to reproduce:

1. Start Firefox with a clean profile.
2. Play an AV1 video from yt.
3. Disable the RDD process, restart Firefox and repeat 2.

Observe the CPU usage in both steps 2 and 3.

Actual results:

When RDD is disabled, I can see almost the same CPU usage as VP9 for the same content (720p@24fps yt video). Observing the system monitor, I'm seeing ~5% for the Web content process regardless of the status of the RDD process. What changes when RDD is enabled is that, in addition to that ~5%, there is another ~11% used by RDD. The average total CPU usage rises from ~10% to ~25% (laptop with 4cores 8threads).

Expected results:

I would have expected AV1 playback to use about the same CPU regardless of the RDD process being enabled or disabled. Not sure if that's a valid expectation, but I thought it was better to file a bug, just in case.

This doesn't seem to be a regression. I wasn't sure if a performance profile would be useful or what threads to capture so I won't include one unless it's asked, in which case, please, specify the needed threads.

Comment 1

[Jean-Yves Avenard [:jya]]

Extra CPU usage is to be expected with the RDD as now everything needs to be copied 2 times more (content->rdd->content->gpu)

Comment 2

[Nils Ohlmeier [:drno]]

My guess is that the extra overhead is basically what is described in bug 1539043

Comment 3

[Michael Froman [:mjf]]

We're currently using AOM to decode on RDD, not DAV1D. Alex is working this in Bug 1538474.

Comment 4

[Alex Chronopoulos [:achronop]]

I think we can make this one a dup of 1538474.