1669376 - Extremely elevated memory usage by Facebook

Status: UNCONFIRMED

(Core :: JavaScript Engine, defect, P2)

Description

[warhorus]

Attachment: memory-report.json.gz

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0

Steps to reproduce:

Started Firefox in Safe Mode with Facebook in a pinned tab. Proceeded to use it for chatting and scrolling the home feed off-and-on for a few hours.

Actual results:

The tab became sluggish and borderline unusable, and in about:performance I can see that the tab has crept up to over a gig's worth of memory, with the next highest tab being 120MB.

Expected results:

Within a few hours worth of usage, it shouldn't be necessary to manually run "Minimize memory usage" over in about:memory?verbose or kill the thread associated with the Facebook tab through task manager. Unfortunately it currently requires me to do this multiple times a day.

Comment 1

[warhorus]

Attachment: Results of about:support

Comment 2

[Andrew McCreight [:mccr8]]

The memory report here looks very similar to the one in bug 1674295: over a GB of JS classes and 256MB of JS strings.

Comment 3

[Andrew McCreight [:mccr8]]

Steven, is there anybody who could look at this? Between this and bug 1674295 there are two reports of very high JS memory on Facebook, which seems bad. It would be good if we could understand the issue better. Thanks.

I'll try leaving a pinned tab with Facebook in it to see if I can reproduce the issue.

Comment 4

[Steven DeTar [:sdetar]]

Jonco, is this something you could investigate? Or help me identify who on our team might be the best person to look at it?

Comment 5

[Jon Coppeard (:jonco)]

I don't think this is a GC problem per se. It's more that facebook allocates tons of memory and we don't always handle that well. I think there are likely improvements we can make both in the GC and more generally across the browser.