1279724 - Firefox severly slows down when playing video on youtube with Inspector on

Status: RESOLVED WORKSFORME

(DevTools :: Inspector, defect, P3)

Description

[hello]

User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0
Build ID: 20160604131506

Steps to reproduce:

I play a youtube video while inspecting elements (inspector/developer tools).

Real life example: i am developing a website and i am debugging it's css, while listening to youtube music in another tab.

It can be reproduced in a clean install or when all addons are disabled and in safe mode.


Actual results:

It slows down to a halt and becomes unresponsive unless I close the inspector. If the inspector is closed firefox goes back to normal.


Expected results:

Should be slowing down.

Comment 1

[hello]

Also the bug is constant with the Web Developer addon.

Comment 2

[ovidiu boca[:Ovidiu]]

Hi,

i tested this issue on Win 10 x64 with FF 47 release and FF 50.0a1 and I can't reproduce it. Everything works as expected.

Comment 3

[Patrick Brosset <:pbro>]

I couldn't reproduce this bug on macOS with FF48 and FF50 either.
I've tried using devtools in the same youtube tab and in another tab as described in comment 0.

Is it the whole Firefox UI that becomes slow? Or just the devtools UI?
Are there any errors shown in the browser console when Firefox is slow (you can open this console with ctrl+shift+J or cmd+shift+J).

This should really be a P1, but since we're not finding reliable ways to reproduce this so far, let's keep it as an unconfirmed P3 for now.

Comment 4

[julesmyers2011]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:47.0) Gecko/20100101 Firefox/47.0

Unable to reproduce the issue. Tried to reproduce in both Firefox 47.0 and Nightly Build 50.01a, but unable too. 

I constantly had youtube playing Madonna while in the other tab going to different websites while the inspector was open and clicking around in the inspector. At some point I had the inspector open in the youtube tab once again clicking around in the inspector while a video was playing. Unable to reproduce the issue.

Comment 5

[Mike Taylor [:miketaylr]]

hello, can you clarify on steps to reproduce?

Do you have youtube playing in a background tab, or in a separate window?
Do you have e10s enabled/disabled?
Does this still reproduce?
Any specific pages you can give us to test would be helpful, thanks!

Comment 6

[Patrick Brosset <:pbro>]

Going to close this since I don't think anyone has been able to reproduce and we didn't get more info from the logger.