1448405 - Firefox takes 100% CPU for 5-10 seconds when opening

Status: RESOLVED INCOMPLETE

(Toolkit :: Startup and Profile System, defect)

Description

[Hans S.]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Steps to reproduce:

Open Firefox


Actual results:

100% CPU for 5-10 seconds


Expected results:

Low to mediocre CPU usage.

Why is this happening? Because the devs have STILL NOT IMPLEMENTED an option, to keep Firefox persistence in memory in the background, like Edge and Chrome do.

Give option to let Firefox stay in memory/background/systray.

Comment 1

[Daniel_A[:daschilean] [Please contact - [e-mail]]]

Hi Hans S.,

I verified this issue on Windows 10 64bit with FF 59.0.2 (2018-03-27) and I cannot reproduce it.

Please test if the issue is reproducible in safe mode, here is a link that can help you:
https://support.mozilla.org/t5/Procedures-to-diagnose-and-fix/Troubleshoot-Firefox-issues-using-Safe-Mode/ta-p/1687#w_how-to-start-firefox-in-safe-mode.
I the issue is still reproducible, please download Firefox Nightly from here: https://nightly.mozilla.org/ and retest the problem. 
 If you still have the issue please create a new profile, you have the steps here:https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles?redirectlocale=en-US&redirectslug=Managing-profiles#w_starting-the-profile-manager

Comment 2

[Hans S.]

(In reply to Daniel_A from comment #1)
> Hi Hans S.,
> 
> I verified this issue on Windows 10 64bit with FF 59.0.2 (2018-03-27) and I
> cannot reproduce it.
> 
> Please test if the issue is reproducible in safe mode, here is a link that
> can help you:
> https://support.mozilla.org/t5/Procedures-to-diagnose-and-fix/Troubleshoot-
> Firefox-issues-using-Safe-Mode/ta-p/1687#w_how-to-start-firefox-in-safe-mode.
> I the issue is still reproducible, please download Firefox Nightly from
> here: https://nightly.mozilla.org/ and retest the problem. 
>  If you still have the issue please create a new profile, you have the steps
> here:https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-
> firefox-profiles?redirectlocale=en-US&redirectslug=Managing-
> profiles#w_starting-the-profile-manager

Please test it on a tablet with a 4Watt CPU (Core M for example, Broadwell-y) and not on a desktop with a 90Watt CPU, where you can't see the CPU usage...

Comment 3

[Daniel_A[:daschilean] [Please contact - [e-mail]]]

Can you please capture a performance profile? You can get more info on how to install and use the Cleopatra add-on (that helps you get the performance profile) by going to:
https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler
https://perf-html.io/

Comment 4

[Hans S.]

(In reply to Daniel_A from comment #3)
> Can you please capture a performance profile? You can get more info on how
> to install and use the Cleopatra add-on (that helps you get the performance
> profile) by going to:
> https://developer.mozilla.org/en-US/docs/Mozilla/Performance/
> Profiling_with_the_Built-in_Profiler
> https://perf-html.io/

That wont help anything. The issue here is Firefox starting up, not a site loading this addon can analyze. Firefox does "too much" when it starts, the addon would just even be loaded after this, so it wont give an insight of what Firefox does when it starts in its first seconds. I tried to set a blank page when Firefox starts, this helps a little bit, maybe takes 30-50% of the time of 100% CPU usage away, still there's is a peak. The only good solution to this is in my understanding, to give an option, to keep Firefox in memory/systray, after it is loaded once. I don't want to keep an empty tab open all the time, just to keep Firefox open faster once it was loaded. This wont be a problem on desktops, but on "slower" machines like a tablet, it is a huge issue. You close a browser all the time on a tablet, and you don't want to have it take 100% every time you open it for 2-3 seconds.

Comment 5

[Daniel_A[:daschilean] [Please contact - [e-mail]]]

Hi Hans S.,

I manage to reproduce this issue with Tablet Acer Iconia w3-810 on Windows 8 32bit with Firefox Beta 60.0b8(2018-03-29) and	Firefox Nightly 61.0a1(2018-04-01). Please note that the 99% CPU is displayed for 2-3 seconds.

Comment 6

[:Paolo Amadini]

(In reply to Hans S. from comment #4)
> That wont help anything. The issue here is Firefox starting up, not a site
> loading this addon can analyze.

Mike might have suggestions on how to capture a profile for the startup phase of Firefox.

Comment 7

[Hans S.]

A simple workaround for this would be (also wanted feature request), to give option to let Firefox run in the background (minimized to systray), after all windows/tabs are closed. Chrome has it, Edge has it (integrated into Windows). The startup time of Firefox is too long and takes too much CPU especially on smaller devices like tablets.

Comment 8

[Mike Conley (:mconley) (:⚙️)]

Hi Daniel_A,

Would you be able to reproduce again on a Nightly build, but with the Gecko Profiler installed, and MOZ_PROFILER_STARTUP environment variable set to 1? That will capture samples starting from very early on in the Firefox lifecycle, and then the Gecko Profiler add-on can be used to dump the profile. Could you then please post it to this bug?

(In reply to Hans S. from comment #7)
> A simple workaround for this would be (also wanted feature request), to give
> option to let Firefox run in the background (minimized to systray), after
> all windows/tabs are closed.

Hi Hans S,

Thanks for reporting this issue.

Yes, I would consider that a feature request - and while that might wallpaper over the CPU usage here, let's have this bug be the CPU usage investigation in general. I encourage you to file a new bug for the feature request.

Comment 9

[Hans S.]

There are already enough feature requests for this since years and no one cared. Care for it, or consider Firefox unusable on tablets and ultrabooks.

Comment 10

[Mike Conley (:mconley) (:⚙️)]

(In reply to Hans S. from comment #9)
> There are already enough feature requests for this since years and no one
> cared. Care for it, or consider Firefox unusable on tablets and ultrabooks.

Great, thanks Hans. I'm glad to hear that this is already being tracked in Bugzilla. Do you have a bug number handy so we can reference it here?