New Firefox release hogging CPU

[Michał Sawicz]

Since the new Firefox release into 16.04 yesterday [1] Firefox is constantly using more than 100% CPU.

[1] https://launchpad.net/ubuntu/+source/firefox/46.0+build5-0ubuntu0.16.04.2

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: firefox 46.0+build5-0ubuntu0.16.04.2
ProcVersionSignature: Ubuntu 4.4.0-22.38-generic 4.4.8
Uname: Linux 4.4.0-22-generic x86_64
AddonCompatCheckDisabled: False
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: michal 8674 F.... pulseaudio
 /dev/snd/controlC0: michal 8674 F.... pulseaudio
BrokenPermissions:
 <email address hidden>/indexes/exclude.dat (0o400)
 <email address hidden>/indexes/include.dat (0o400)
 <email address hidden>/indexes/info.ini (0o400)
 <email address hidden>/indexes/scripts.db (0o400)
BuildID: 20160425114621
Channel: Unavailable
CurrentDesktop: Unity
Date: Fri Apr 29 10:35:53 2016
ForcedLayersAccel: False
IncompatibleExtensions:
 Polski Language Pack - <email address hidden>
 Default - {972ce4c6-7e08-4474-a285-3208198ce6fd}
Plugins:
 Google Talk Plugin Video Renderer - /opt/google/talkplugin/libnpo1d.so (google-talkplugin)
 Google Talk Plugin - /opt/google/talkplugin/libnpgoogletalk.so (google-talkplugin)
 Shockwave Flash - /usr/lib/flashplugin-installer/libflashplayer.so
 IcedTea-Web Plugin (using IcedTea-Web 1.6.2 (1.6.2-3ubuntu1)) - /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so (icedtea-8-plugin)
PrefSources:
 prefs.js
 [Profile]/<email address hidden>/defaults/preferences/preferences.js
Profiles: Profile0 (Default) - LastVersion=46.0/20160425114621 (In use)
RelatedPackageVersions:
 google-talkplugin 5.41.0.0-1
 icedtea-8-plugin 1.6.2-3ubuntu1
RunningIncompatibleAddons: True
SourcePackage: firefox
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/15/2014
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A06
dmi.board.name: XPS 12-9Q33
dmi.board.vendor: Dell Inc.
dmi.board.version: A06
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: Not Specified
dmi.modalias: dmi:bvnDellInc.:bvrA06:bd04/15/2014:svnDellInc.:pnXPS12-9Q33:pvrA06:rvnDellInc.:rnXPS12-9Q33:rvrA06:cvnDellInc.:ct8:cvrNotSpecified:
dmi.product.name: XPS 12-9Q33
dmi.product.version: A06
dmi.sys.vendor: Dell Inc.

[Michał Sawicz (saviq)]

   9,45% DOM Worker libxul.so [.] _ZL27TypedArray_byteLengthGetterP9JSContextjPN2JS5ValueE

This is the top offender by perf, see the top part of perf report for a spinning firefox process.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[fermulator (fermulator)]

following the firefox PID
{{{
top - 11:46:42 up 1 day, 13:37, 3 users, load average: 4.20, 4.02, 4.04
Threads: 64 total, 3 running, 61 sleeping, 0 stopped, 0 zombie
%Cpu(s): 20.5 us, 9.1 sy, 0.0 ni, 64.7 id, 5.6 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 32777012 total, 4357160 free, 12640692 used, 15779160 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 18872148 avail Mem

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
12094 fermula+ 20 0 2886256 657056 130136 R 90.3 2.0 6:14.75 DOM Worker <--- THIS
11838 fermula+ 20 0 2886256 657056 130136 R 50.3 2.0 3:21.63 Timer
11819 fermula+ 20 0 2886256 657056 130136 R 5.3 2.0 1:33.61 firefox
11853 fermula+ 20 0 2886256 657056 130136 S 0.7 2.0 0:00.77 JS Helper
11889 fermula+ 20 0 2886256 657056 130136 S 0.7 2.0 0:01.42 GLXVsyncThread
11890 fermula+ 20 0 2886256 657056 130136 S 0.7 2.0 0:02.52 GLXVsyncThread
11844 fermula+ 20 0 2886256 657056 130136 S 0.3 2.0 0:00.87 JS Helper
11848 fermula+ 20 0 2886256 657056 130136 S 0.3 2.0 0:00.89 JS Helper
11850 fermula+ 20 0 2886256 657056 130136 S 0.3 2.0 0:00.95 JS Helper
11880 fermula+ 20 0 2886256 657056 130136 S 0.3 2.0 0:04.57 Compositor
}}}

[fermulator (fermulator)]

$ dpkg --list | grep firefox
ii firefox 54.0+build3-0ubuntu0.16.04.1 amd64 Safe and easy web browser from Mozilla

[fermulator (fermulator)]

Mozilla Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1349874

[fermulator (fermulator)]

For now, workaround = disable gnome shell extension

[Paul White (paulw2u)]

Upstream bug #1349874 was closed "RESOLVED WORKSFORME" on 2017-03-23
with the implication that the problem was fixed in or around Firefox 55.

Now that Firefox 67 is the currently supported release in Ubuntu, is
there any reason for this bug report to remain open or can the issue
now be regarded as being fixed?

[Paul White (paulw2u)]

Bug report did not expire due to bug watch.
Further to comment #8, now closing as fixed.