1939920 - High RAM usage and performance degradation on YouTube

Status: UNCONFIRMED

(Core :: Performance, defect)

Description

[Almtst]

Attachment: Memory Report

When repeatedly opening multiple YouTube channels in the same tab, RAM usage steadily increases, leading to significant performance degradation. This manifests as noticeable delays when performing actions like pausing or fast-forwarding videos. While Microsoft Edge also exhibits increased RAM usage under similar conditions, it eventually releases the memory and maintains smooth performance, unlike Firefox.

Steps to Reproduce:

1. Install the uBlock Origin extension (without this extension, the issue is not consistently reproducible).
2. Bookmark a YouTube channel (e.g., https://www.youtube.com/@veritasium/videos).
3. Open the bookmarked channel from the bookmarks bar and wait for all page elements to load completely.
4. Repeat step 3 approximately 15 times in the same tab (more repetitions may be required depending on the system).
5. Open any video from the channel in the same tab.

Actual Results:

• RAM usage increases steadily with each repetition.
• Actions like pausing or fast-forwarding videos have a delay of several seconds.
• The memory is not freed up, and performance continues to degrade over time.

Expected Results:

• RAM usage should stabilize after each operation.
• Video playback and controls should remain responsive regardless of the number of repetitions.
• Memory should be released efficiently, as observed in Microsoft Edge.

Additional Information:
Setting the browser.sessionhistory.max_total_viewers preference to 0 seems to reduce the issue's impact but does not fully resolve it.

Profile: https://share.firefox.dev/3DJN9yz

Comment 1

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

This bug was moved into the Performance component.

:alamalo.exe, could you make sure the following information is on this bug?

• ✅ For slowness or high CPU usage, capture a profile with http://profiler.firefox.com/, upload it and share the link here.
• ✅ For memory usage issues, capture a memory dump from about:memory and attach it to this bug.
• Troubleshooting information: Go to about:support, click "Copy raw data to clipboard", paste it into a file, save it, and attach the file here.

If the requested information is already in the bug, please confirm it is recent.

Thank you.

Comment 2

[Andrew McCreight [:mccr8]]

The profile shows that the heavy CPU usage is happening with the cycle collector. The memory report doesn't show ghost windows, but there are a lot of windows alive. This could be another instance of bug 1930031. We released an update that fixes at least one YouTube issue, two days ago. Please update your Firefox and see if you are still experiencing this issue. Thanks.

Comment 3

[Andrew McCreight [:mccr8]]

Sorry, I meant bug 939295.

Comment 4

[Andrew McCreight [:mccr8]]

Eventually I'll get the right bug. I meant bug 1939295.