1621312 - Massive Lag When Switching Languages while having Firefox Active on Windows

Status: RESOLVED INVALID

(Core :: Widget: Win32, defect)

Description

[Ringil]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:74.0) Gecko/20100101 Firefox/74.0

Steps to reproduce:

1. Leave Firefox on for some time (typically this happens after 1-2 days of the program running)
2. Switch Language Input via language bar hotkey from English to Japanese on Windows.

Actual results:

Massive Lag that freezes up Firefox for over 10 seconds

Expected results:

No/minimal lag. Switching languages does not cause other applications such as Chrome from lagging.

Comment 1

[Seba S.]

Hi, ringil.sword!

Thanks for your contribution!

I couldn't reproduce the described behavior in:

Windows 10 Pro
Firefox 75.0b3 (64-bit)
Firefox Nightly 76.0a1 (2020-03-18) (64-bit)

Please let us know if this issue is reproduced in the latest Nightly edition. You can download it from here: https://nightly.mozilla.org/

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
support.mozilla.orgsupport.mozilla.org

Once you have all this information, please let us know so we can continue investigating.

Regards,

Comment 2

[Ringil]

Hi,

I tried on the latest Nightly and it was still an issue. I record a profiler on the developer edition. As you can see there is an approximate delay of 6 seconds before Firefox responds again after I activate the language switch.

https://bit.ly/33HTzYY

Comment 3

[Ringil]

Hello,

I created a fresh profile with Nightly and have set up the situation.

Here's a profiler run
https://profiler.firefox.com/public/8dcf972772ef02c6eab4c489cc43489717b3587e/calltree/?globalTrackOrder=14-15-0-1-2-3-4-5-6-7-8-9-10-11-12-13&hiddenGlobalTracks=1-2-3-4-5-6-7-8-9-10-11-12&hiddenLocalTracksByPid=1168172-1-2&localTrackOrderByPid=60484-1-2-0~73036-0~69708-0~817116-0-1~949668-0-1~588104-0~82020-0~946552-0-1~945068-0~81396-0-1~74188-0-1~74564-0-1~63684-0~1168172-3-0-1-2~&thread=0&v=4

As you can see there are long parent process event processing delay of around 1 second. It gets worse as the process is alive longer.

I'm willing to create a memory dump for the process. However, attempting to follow the instructions https://developer.mozilla.org/en-US/docs/Mozilla/Debugging/Capturing_a_minidump do not work as the debugger cannot attach to the Nightly. Do I need to enable a debug setting for the Nightly build to allow debugging? If so can you direct me to any documentation for that?

Thanks

Comment 4

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

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 5

[Jessie [:jbonisteel] pls NI]

Can you attach the contents of about:support as a text file?

Comment 6

[Ringil]

Attachment: support.txt

Comment 7

[Ringil]

Attachment: support-text.txt

Comment 8

[Jeff Muizelaar [:jrmuizel]]

The profile has big chunks of time spent in imetip.dll. This looks like an IME problem.

Comment 9

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

The priority flag is not set for this bug.
:jimm, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 10

[Firefox Bug Husbandry Bot]

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is -- (Backlog,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

Comment 11

[Firefox Bug Husbandry Bot]

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is -- (Backlog,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

Comment 12

[Firefox Bug Husbandry Bot]

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is -- (Backlog,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

Comment 13

[Firefox Bug Husbandry Bot]

The severity of these bugs was changed, mistakenly, from normal to S3.

Because these bugs have a priority of --, indicating that they have not been previously triaged, these bugs should be changed to Severity of --.

Comment 14

[Ringil]

Okay it does appear to be a Microsoft IME bug. Thanks for the assistance.