1448278 - Web Twitter spends multiple seconds performing GC and CCs due to orphan nodes

Status: RESOLVED DUPLICATE of bug 1447871

(Core :: JavaScript: GC, defect, P1)

Description

[Katelyn Gadd (:kael)]

Attachment: memory-report.json.gz

As of late web twitter is performing very badly in Firefox. It hitches up for hundreds to thousands of milliseconds and it's using a lot of memory. Performance profiles show the hitches are GCs/CCs (some of the collections block for over a second). According to about:memory it looks like my twitter tab has hundreds of megabytes worth of orphaned nodes even though I've reloaded the tab recently.

Comment 1

[Katelyn Gadd (:kael)]

Attachment: twitter.profile.json

Attaching a performance profile as well.

Comment 2

[Katelyn Gadd (:kael)]

Shift-reloading the tab actually makes it worse, leaking additional memory. Mashing GC/CC/Minimize on the about:memory page does not free any of the leaked memory, but does make the browser considerably slower.

Comment 3

[Jon Coppeard (:jonco)]

(In reply to K. Gadd (:kael) from comment #2)
The profile shows 9% of time in CC and 5% in GC (CC_WAITING).

> Mashing GC/CC/Minimize on the about:memory page does not free any of the
> leaked memory

This implies that it might be a leak in the page, and not a GC/CC issue.

CC Andrew for cycle collector relevance.

Comment 4

[Ryan VanderMeulen [:RyanVM]]

This is marked as a P1, so I went ahead and took it as tracking61+ as well, but it doesn't seem very clear who owns the next step here either.

Comment 5

[Andrew McCreight [:mccr8]]

(In reply to K. Gadd (:kael) from comment #0)
> Created attachment 8961688 [details]
> memory-report.json.gz
> 
> As of late web twitter is performing very badly in Firefox. It hitches up
> for hundreds to thousands of milliseconds and it's using a lot of memory.
> Performance profiles show the hitches are GCs/CCs (some of the collections
> block for over a second). According to about:memory it looks like my twitter
> tab has hundreds of megabytes worth of orphaned nodes even though I've
> reloaded the tab recently.

Are you still seeing this? 60 and 61 were affected by bug 1447871, which causes ghost windows, and I see a few ghost windows in your about:memory report. Ghost windows are the most common cause of long CCs. RyanVM told me that they should both have a fix now.

Comment 6

[Katelyn Gadd (:kael)]

My dev edition channel is still on 60.0b9, so would I need 62?

Comment 7

[Ryan VanderMeulen [:RyanVM]]

DevEdition tracks Beta these days. 60.0b9 has the fix in question.

Comment 8

[Katelyn Gadd (:kael)]

Seems fixed now.

Comment 9

[Ryan VanderMeulen [:RyanVM]]

Thanks for double-checking!