Mio, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com /daily-live/current/ .
If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report: apport-collect -p linux <replace-with-bug-number> Also, could you please test the latest upstream kernel available following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Please do not test the daily folder, but the one all the way at the bottom. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags: kernel-fixed-upstream kernel-fixed-upstream-VERSION-NUMBER where VERSION-NUMBER is the version number of the kernel you tested. For example: kernel-fixed-upstream-v3.11-rc5 This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag: needs-upstream-testing If the mainline kernel does not fix this bug, please add the following tags: kernel-bug-exists-upstream kernel-bug-exists-upstream-VERSION-NUMBER As well, please remove the tag: needs-upstream-testing Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding. ** This bug is no longer a duplicate of bug 887793 Kworker constantly taking about 100% CPU ** Tags added: needs-full-computer-model needs-upstream-testing regression-potential -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1087010 Title: kworker uses 70-90% of a CPU core (hyperthreaded) Status in “linux” package in Ubuntu: Incomplete 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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