1933343 - Typing in the console causes lag on already resource intensive pages

Status: UNCONFIRMED

(DevTools :: Console, defect)

Description

[Antti Ellilä]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0

Steps to reproduce:

Not sure what kind of pages exactly this issue happens on but I stumbled upon it working with resource intensive Three.js pages.

• Open https://threejs.org/examples/webgl_instancing_performance.html
• Set method to naive and count to something like 5000 where your device still runs it smoothly
• Observe fps still being 60 (or whatever)
• Open the console (Ctrl + Shift + K)
• Input anything such as a single symbol "1"
• Observe fps dropping to below 10

Actual results:

Typing anything in the console causes the page to lag a lot.

Expected results:

The page shouldn't lag.

Comment 1

[Antti Ellilä]

The bug submission form forced that format so here's extra info as a comment:

This is a regression as this used to work properly
Bisected this on mozilla-unified with git
This bug was introduced by

• git commit 6341e910024ce8993f5ecbb0fe9b23a1e3281fcc
• https://phabricator.services.mozilla.com/D195178
• https://hg.mozilla.org/mozilla-central/rev/97f759dedbc9028323bba1817bba400e8c09e9de

Here's a profile of the issue on 133:

• https://share.firefox.dev/4fM8dTk
  Here's a profile from the previous commit (git 47d2eb542e1931694f2532e65c4afe0a27b46d08):
• https://share.firefox.dev/4eOXAOe

Comment 2

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

The Bugbug bot thinks this bug should belong to the 'DevTools::Console' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

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

:ochameau, since you are the author of the regressor, bug 1867668, could you take a look? Also, could you set the severity field?

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