1738148 - Firefox very slow with several Google Docs tabs open Zoom desktop app running

Status: RESOLVED INVALID

(Core :: Performance, defect)

Description

[Haik Aftandilian [:haik]]

Attachment: about:support

Basic information

I'm filing this bug on behalf of a colleague experiencing very slow responsiveness in Firefox 93 (Fission not enabled) when several Google docs tabs are loaded. User notices the problem more when the Zoom desktop app is running. At least one doc is a ~100 pages long. Sometimes the delay when entering text is several seconds.

On opening the doc, CPU usage of a Web Content process was over 100% for (I estimate) a minute before reducing.

More information

Profile collected with one 100 page Google doc open: https://share.firefox.dev/30YO0rG

Basic systems configuration:

MacBook Pro 15-inch 2018
2.8 GHz 6-Core Intel Core i9
Radeon Pro 560X 4 GB
Intel UHD Graphics 630 1536 MB
macOS 12.0.1 (problem was occurring with macOS 11 too)
32GB

Comment 1

[Haik Aftandilian [:haik]]

With a large number of Google docs open, the limit of 8 content processes might be limiting for this laptop. I'll ask to test with a higher process count.

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

Responsiveness problem....
Paul - this seems similar to the problems you were having in webrtc calls

Comment 3

[Paul Adenot (:padenot)]

I see it's making a lot of network requests to fetch part of the document, and executing lots of js, and of course the event loop is delayed very frequently.

It seems like network requests are delayed a lot, for example an icon taking 3s to arrive, or waits for 300ms for the socket thread, this kind of thing. This seem to indicate a rather extreme load and Firefox's main thread isn't being scheduled, or is context switching too much.

Comment 4

[Randell Jesup [:jesup] (needinfo me)]

Was this profile taken with Zoom running? How many people in Zoom? screensharing?
What did system CPU monitor say during this? 100%? Does it show how much zoom is using when firefox is idle-ish? (and how much CPU is free)
Was the system under memory pressure? (Memory tab in activity monitor)

Does the doc have pagebreaks, or does it flow to the end of the 100 page doc?

Thanks

Comment 5

[Randell Jesup [:jesup] (needinfo me)]

Also: this profile is very limited. Looks like it was taken with something like a JS preset, and maybe was restricted to only a single visible thread. A Platform preset would be far more helpful. (You could also add IPC logging, though that's not required). For example, we can't see the main process at all here, so if there are issues there we can't see them

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

Yeah, that profile doesn't give much information.

Steps to reproduce would be really great here.

Comment 7

[Haik Aftandilian [:haik]]

I'll work on getting answers to more of these questions.

(In reply to Randell Jesup [:jesup] (needinfo me) from comment #4)

Was this profile taken with Zoom running? How many people in Zoom? screensharing?

I believe this profile was with Zoom running with a two-person meeting without screensharing.

What did system CPU monitor say during this? 100%? Does it show how much zoom is using when firefox is idle-ish? (and how much CPU is free)
Was the system under memory pressure? (Memory tab in activity monitor)

Activity Monitor showed Zoom using less than 100% and some Firefox Content processes staying at high CPU (over 100% and up to 250%) for 1 or 2 minutes.

Does the doc have pagebreaks, or does it flow to the end of the 100 page doc?

I'll work with Phyllis to get access to the document or a similar document that reproduces the problem.

Comment 8

[Alex Thayer [:alexical] (she/her)]

Haik - just checking in in case this fell off your radar, but are you still working on getting more information?

Comment 9

[Haik Aftandilian [:haik]]

(In reply to Doug Thayer [:dthayer] (he/him) from comment #8)

Haik - just checking in in case this fell off your radar, but are you still working on getting more information?

Yes, still working on this. We had trouble scheduling debug time before the holidays but we will pick this back up.

Comment 10

[Haik Aftandilian [:haik]]

The MacBook Pro being used turned out to have a swollen battery and was serviced and then donated. The replacement machine is an M1 Max and not exhibiting any of the earlier problems (which isn't surprising given it is a faster machine).

The large Google doc that seemed to be triggering the problem has private information and can't be shared, but the linked Google doc below is considered similar. It is approximately 70 pages and contains a mix of text, pictures, styles, and fonts.

https://docs.google.com/document/d/1SlqylSD_XQ0Gp5SO5NQXqLSuHx7-iM8WXHwfCZeyvF0/edit?usp=sharing

It is plausible that the swollen battery on the original machine was causing or triggered by overheating which could have caused CPU throttling leading to the lack of responsiveness, but we can't be sure as the machine is no longer available.

On the same model of MacBook Pro, I have not been able to reproduce the problem.