Xorg consuming 50% CPU for no good reason, at-spi2-registr another 20%, non-stop since boot

[teo1978]

I have booted the computer about half an hour ago. Since the very beginning, I noticed the fan spinning at high spin so I launched "top", and noticed that Xorg was consuming about 50% CPU and another process called "at-spi2-registr" is consuming another 20%.

Since then, They have continued consuming that amount of CPU constantly, all the time, whether or not I was doing anything. The only applications I opened are a terminal where I'm running top and the browser where I've been browsing Facebook. Before I launched the browser and after I closed it, CPU usage by these processed has never gone below 50% and 20% respectively.

This is fucking ridiculous.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-122.146-generic 4.4.117
Uname: Linux 4.4.0-122-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
.proc.driver.nvidia.gpus.0000.01.00.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0000:01:00.0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 340.104 Thu Sep 14 17:13:13 PDT 2017
 GCC version: gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.9)
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.16
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Fri May 18 22:17:40 2018
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] 3rd Gen Core processor Graphics Controller [1025:0647]
 NVIDIA Corporation GF117M [GeForce 610M/710M/810M/820M / GT 620M/625M/630M/720M] [10de:1140] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] GeForce 710M [1025:0691]
InstallationDate: Installed on 2013-10-11 (1680 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: Acer Aspire V3-571G
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-122-generic.efi.signed root=UUID=5830b30e-69e8-4bb4-8a2b-bc2b43c7414a ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/15/2012
dmi.bios.vendor: Acer
dmi.bios.version: V2.07
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: VA50_HC_CR
dmi.board.vendor: Acer
dmi.board.version: Type2 - Board Version
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V2.07
dmi.modalias: dmi:bvnAcer:bvrV2.07:bd10/15/2012:svnAcer:pnAspireV3-571G:pvrV2.07:rvnAcer:rnVA50_HC_CR:rvrType2-BoardVersion:cvnAcer:ct10:cvrV2.07:
dmi.product.name: Aspire V3-571G
dmi.product.version: V2.07
dmi.sys.vendor: Acer
version.compiz: compiz 1:0.9.12.3+16.04.20180221-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.83-1~16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 17.2.8-0ubuntu0~16.04.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 17.2.8-0ubuntu0~16.04.1
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.18.4-0ubuntu0.7
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Fri May 18 21:44:15 2018
xserver.configfile: /etc/X11/xorg.conf
xserver.errors:
 NVIDIA(0): Failed to initiate mode change.
 NVIDIA(0): Failed to complete mode change
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.4-0ubuntu0.7

[teo1978 (teo8976)]

Interestingly, killing the "at-spi2-registr" process has made Xorg's CPU consumption go down to normal.

[Paul White (paulw2u)]

Ubuntu 16.04 (xenial) reached end-of-standard-support on April 29, 2021.
User was removed from Launchpad some time ago so closing.