Tested, and if anything the %CPU of kworker threads is even higher,
often staying around 65% in 'top'.
An easy way to get the screen to update is to run glxgears, which should
run at screen refresh rate with very low CPU usage.
** Tags added: kernel-bug-exists-upstream
** Changed in: linux (Ubuntu)
Status: Incomplete => Confirmed
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https://bugs.launchpad.net/bugs/1744543
Title:
Screen updating with Compiz causes high-CPU kworker thread in 4.13 or
earlier
Status in linux package in Ubuntu:
Confirmed
Bug description:
This duplicates the information in
https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1744515. Filing
this to get more exposure.
The automatically-included information for this reports notes that I'm
using kernel 4.8, where this issue doesn't occur. I don't have any
other kernels to test with.
When the screen updates in 4.13 while running Compiz, it causes high
CPU usage in a kworker thread. This was 30~40% of a CPU core on my
system. This doesn't happen with other window managers tested, like
Metacity, or whatever non-Compiz Gnome and Ubuntu use (gnome-shell
maybe, though that 15% CPU load more than Metacity when I checked).
Since Unity uses Compiz, it happens there as well as with 'Ubuntu
flashback Compiz'.
This seems unrelated to how much of the screen is being repainted, as
the 'Show Repaint' plugin in Compiz can show that only a few pixels
are being updated and the kworker load is the same.
ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: linux-generic 4.13.0.25.26
ProcVersionSignature: Ubuntu 4.8.0-34.36-generic 4.8.11
Uname: Linux 4.8.0-34-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/pcmC0D0p: misaki 1685 F...m pulseaudio
/dev/snd/controlC0: misaki 1685 F.... pulseaudio
CurrentDesktop: GNOME-Flashback:GNOME
Date: Sun Jan 21 00:17:16 2018
HibernationDevice: RESUME=UUID=ea8d7b22-9a3e-412e-af6a-8fc260a76a2c
MachineType: ASUSTeK Computer Inc. N50Vn
ProcFB: 0 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.8.0-34-generic
root=UUID=b09dc720-93ec-4fdf-a42f-7ea19a9af555 ro quiet splash vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-4.8.0-34-generic N/A
linux-backports-modules-4.8.0-34-generic N/A
linux-firmware 1.169.1
SourcePackage: linux
UpgradeStatus: Upgraded to artful on 2018-01-09 (12 days ago)
WpaSupplicantLog:
dmi.bios.date: 03/05/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 211
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: N50Vn
dmi.board.vendor: ASUSTeK Computer Inc.
dmi.board.version: 1.0
dmi.chassis.asset.tag: ATN12345678901234567
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer Inc.
dmi.chassis.version: 1.0
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvr211:bd03/05/2009:svnASUSTeKComputerInc.:pnN50Vn:pvr1.0:rvnASUSTeKComputerInc.:rnN50Vn:rvr1.0:cvnASUSTeKComputerInc.:ct10:cvr1.0:
dmi.product.name: N50Vn
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK Computer Inc.
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