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Message #44323
[Bug 1087010] Re: kworker uses 70-90% of a CPU core (hyperthreaded)
I have 12.04, but I try all availiable kernels from 12.10, 13.04, 13.10
and this bug affect me
** Changed in: linux (Ubuntu)
Status: Expired => New
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https://bugs.launchpad.net/bugs/1087010
Title:
kworker uses 70-90% of a CPU core (hyperthreaded)
Status in “linux” package in Ubuntu:
Confirmed
Bug description:
I see high cpu usage from a kworker thread. Usually kworker/0:1 or kworker/0:2. I tested various kernels from Ubuntu and mainline (3.5.0-x, 3.6.x, 3.7.0-rcx) and they all showed the same behavior. This does not always happen.
I wasn't able to determine on which basis it happens. Some observations that may as well be wrong (duh!):
On some boot all is fine but once it shows, no matter how many reboots it does not seem to want to go away again.
The laptop seems to have to rest a while to have a chance that it won't happen.
If it does not happen a reboot will show the behavior.
I saw similar bug reports in various places but it seems that this can
have a multitude of causes and the presented workarounds or fixes did
not apply to me.
ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: linux-image-3.5.0-19-generic 3.5.0-19.30
ProcVersionSignature: Ubuntu 3.5.0-19.30-generic 3.5.7
Uname: Linux 3.5.0-19-generic x86_64
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: mio 1965 F.... pulseaudio
/dev/snd/pcmC0D0p: mio 1965 F...m pulseaudio
Date: Wed Dec 5 22:37:00 2012
HibernationDevice: RESUME=UUID=a371882c-0fe7-45e5-9adb-83da8374bc11
InstallationDate: Installed on 2012-10-10 (55 days ago)
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
MachineType: SAMSUNG ELECTRONICS CO., LTD. 700Z7C
MarkForUpload: True
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-19-generic root=UUID=79674508-93de-43e0-b313-f6a9b480c606 ro crashkernel=384M-2G:64M,2G-:128M acpi_osi=Linux pcie_aspm=force i915.modeset=1 i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.semaphores=1 i915.powersave=1 snd_hda_intel.power_save_controller=1 snd_hda_intel.power_save=1 quiet splash vt.handoff=7
PulseList:
Error: command ['pacmd', 'list'] failed with exit code 1: Home directory /home/mio not ours.
No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-3.5.0-19-generic N/A
linux-backports-modules-3.5.0-19-generic N/A
linux-firmware 1.95
SourcePackage: linux
UpgradeStatus: Upgraded to quantal on 2012-10-11 (55 days ago)
dmi.bios.date: 08/02/2012
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: P04AAE
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: SAMSUNG_NP1234567890
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: FAB1
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnPhoenixTechnologiesLtd.:bvrP04AAE:bd08/02/2012:svnSAMSUNGELECTRONICSCO.,LTD.:pn700Z7C:pvr0.1:rvnSAMSUNGELECTRONICSCO.,LTD.:rnSAMSUNG_NP1234567890:rvrFAB1:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvr0.1:
dmi.product.name: 700Z7C
dmi.product.version: 0.1
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.
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