I've worked around this issue in Kubuntu Utopic 14.04 with kubuntu- settings 1:14.10ubuntu3 [1]
It would be awesome if someone from the foundations team could have a look into why Ubuntu can't switch back to CFQ. [1] https://launchpad.net/ubuntu/+source/kubuntu-settings/1:14.10ubuntu3 -- 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/1310402 Title: Userland depends on ionice idle but default scheduler is "deadline". Status in “linux” package in Ubuntu: Triaged Bug description: Userland depends upon the idle feature of the CFQ scheduler, this can lead to extreme desktop sluggishness with the default deadline scheduler due to IO blocking. In my case, the KDE baloo indexer was indexing all of my files, and making other desktop processes block. The baloo processes are set to idle IO priority to avoid this problem but this was not being honored. From the information I have found online and in the ionice man page, the idle priority only is useful with the CFQ scheduler. KDE Baloo indexer sets it's processes to use "idle" priority the man-db cronjobs also use idle priority root@sirius:/etc# grep idle cron.daily/man-db iosched_idle= iosched_idle='--iosched idle' --oknodo --chuid man $iosched_idle -- -c \ $iosched_idle \ The compiled in default scheduler is "deadline" root@sirius:/boot# grep DEFAULT_IOSCHED config-3.13.0-24-generic CONFIG_DEFAULT_IOSCHED="deadline" from the ionice man page: Linux supports I/O scheduling priorities and classes since 2.6.13 with the CFQ I/O scheduler. root@sirius:/boot# uname -a Linux sirius 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-generic 3.13.0.24.28 ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9 Uname: Linux 3.13.0-24-generic x86_64 ApportVersion: 2.14.1-0ubuntu3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: zmc 2658 F.... pulseaudio zmc 3010 F.... pulseaudio /dev/snd/controlC0: zmc 2658 F.... pulseaudio zmc 3010 F.... pulseaudio CurrentDesktop: KDE Date: Sun Apr 20 17:23:28 2014 HibernationDevice: RESUME=UUID=dea47071-fda3-4725-a9c5-1f4fc531e6ef InstallationDate: Installed on 2014-04-18 (2 days ago) InstallationMedia: Kubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.1) MachineType: Acer Aspire 7551 ProcFB: 0 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-24-generic root=/dev/mapper/hostname-root ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.13.0-24-generic N/A linux-backports-modules-3.13.0-24-generic N/A linux-firmware 1.127 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/26/2010 dmi.bios.vendor: Phoenix Technologies LTD dmi.bios.version: V1.15 dmi.board.asset.tag: No Asset Tag dmi.board.name: Aspire 7551 dmi.board.vendor: Acer dmi.board.version: V1.15 dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: Acer dmi.chassis.version: V1.15 dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrV1.15:bd10/26/2010:svnAcer:pnAspire7551:pvrV1.15:rvnAcer:rnAspire7551:rvrV1.15:cvnAcer:ct10:cvrV1.15: dmi.product.name: Aspire 7551 dmi.product.version: V1.15 dmi.sys.vendor: Acer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1310402/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
