Pavol Domin, in order to maximize the probability of upstream addressing this issue as fast as possible, you would want to fully commit bisect from kernel 3.19 to 4.2 in order to identify the last good kernel commit, followed immediately by the first bad one. Could you please do this at your convenience following https://wiki.ubuntu.com/Kernel/KernelBisection ?
Please note, finding adjacent kernel versions is not fully commit bisecting. Thank you for your understanding. -- 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/1531951 Title: A severe performance degradation while syncing md raid after the upgrade to 15.10 Status in linux package in Ubuntu: Triaged Bug description: I run Ubuntu from the fakerade (imsm) raid5 volume. If the volume is syncing, the system response is severely degraded. There is no problem if I boot the same system from the previous kernel 3.19.0-32. Some numbers: [md125_resync] kernel thread CPU consumption: 94 per-mill compared to 10 in 3.19 kernel [md125_raid5] kernel thread CPU consumption: 243 per-mill compared to 86 in 3.19 kernel 1MB direct read from md array: 0.5s compared to 0.01s in 3.19 kernel 1MB direct read from md raid member: 2.2s compared to 0.02s in 3.19 kernel As a result, it's practically impossible to work in 4.2 kernel if md raid is syncing (even the boot takes several minutes here), whereas in 3.19 I don't feel any performance degradation at all, regardless the raid volume is syncing or not. ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: linux-image-4.2.0-22-generic 4.2.0-22.27 ProcVersionSignature: Ubuntu 4.2.0-22.27-generic 4.2.6 Uname: Linux 4.2.0-22-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: palo 3869 F.... pulseaudio /dev/snd/pcmC0D0p: palo 3869 F...m pulseaudio /dev/snd/controlC0: palo 3869 F.... pulseaudio CurrentDesktop: Unity Date: Thu Jan 7 18:51:39 2016 HibernationDevice: RESUME=UUID=f9900a93-c16d-4cae-9098-194fdf3abbfe InstallationDate: Installed on 2011-09-16 (1574 days ago) InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1) MachineType: System manufacturer System Product Name ProcFB: 0 VESA VGA ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.2.0-22-generic root=/dev/mapper/vg00-lv_ubuntu_root ro init=/sbin/upstart RelatedPackageVersions: linux-restricted-modules-4.2.0-22-generic N/A linux-backports-modules-4.2.0-22-generic N/A linux-firmware 1.149.3 RfKill: SourcePackage: linux UpgradeStatus: Upgraded to wily on 2016-01-02 (4 days ago) dmi.bios.date: 02/23/2009 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 2102 dmi.board.asset.tag: To Be Filled By O.E.M. dmi.board.name: P5Q-PRO dmi.board.vendor: ASUSTeK Computer INC. dmi.board.version: Rev 1.xx dmi.chassis.asset.tag: Asset-1234567890 dmi.chassis.type: 3 dmi.chassis.vendor: Chassis Manufacture dmi.chassis.version: Chassis Version dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2102:bd02/23/2009:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP5Q-PRO:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion: dmi.product.name: System Product Name dmi.product.version: System Version dmi.sys.vendor: System manufacturer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1531951/+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