apport information ** Attachment added: "ProcInterrupts.txt" https://bugs.launchpad.net/bugs/1219548/+attachment/3798374/+files/ProcInterrupts.txt
-- 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/1219548 Title: sched_autogroup_enabled breaks niceness Status in “linux” package in Ubuntu: Confirmed Bug description: With the default Ubuntu 13.04 sysctl settings and boot parameters, positively niced tasks are very clearly given a larger share of CPU time than they ought to be. The update-apt-xapian-index process, for instance, runs at niceness +19; but it still slows my Celeron M520 laptop to a crawl. Likewise for other positively niced tasks. If, on the other hand, I boot with the 'noautogroup' kernel parameter (which sets kernel.sched_autogroup_enabled to 0), responsiveness is much better when running CPU heavy tasks at positive niceness. In both cases, processes are reported by top and ps as running at the correct niceness; it appears that the nice level is ignored silently. Autogrouping is supposed to provide better responsiveness under some loads, but I believe that breaking nice settings is too high a price. I think it would be a good idea to turn off kernel.sched_autogroup_enabled, until this behavior is fixed upstream. By the way, an important note: modifying the sched_autogroup_enabled sysctl on a running system will usually cause a kernel panic. Autogrouping needs to be turned off using 'noautogroup' as a boot parameter; if you try it using sysctl.conf you will get a nice kernel panic on boot. --- ApportVersion: 2.9.2-0ubuntu8.3 Architecture: i386 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: proteus 1939 F.... pulseaudio CurrentDmesg: [ 23.536912] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 70.086188] nr_pdflush_threads exported in /proc is scheduled for removal [ 70.086403] sysctl: The scan_unevictable_pages sysctl/node-interface has been disabled for lack of a legitimate use case. If you have one, please send an email to linux...@kvack.org. [ 186.829290] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready DistroRelease: Ubuntu 13.04 HibernationDevice: RESUME=UUID=ef3fd95f-4429-4c81-8aa1-30d57be5d48c InstallationDate: Installed on 2013-09-01 (0 days ago) InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release i386 (20130424) MachineType: Acer, inc. Aspire 3680 MarkForUpload: True Package: linux (not installed) PccardctlIdent: Socket 0: no product info available PccardctlStatus: Socket 0: no card ProcEnviron: TERM=xterm PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-29-generic root=UUID=779c7e91-1548-4942-b184-7b10797b86b8 ro quiet splash autogroup vt.handoff=7 ProcVersionSignature: Ubuntu 3.8.0-29.42-generic 3.8.13.5 RelatedPackageVersions: linux-restricted-modules-3.8.0-29-generic N/A linux-backports-modules-3.8.0-29-generic N/A linux-firmware 1.106 Tags: raring Uname: Linux 3.8.0-29-generic i686 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo dmi.bios.date: 10/27/06 dmi.bios.vendor: Acer dmi.bios.version: v1.3216 dmi.board.name: Prespa1 dmi.board.vendor: Acer, Inc. dmi.board.version: Not Applicable dmi.chassis.type: 1 dmi.chassis.vendor: Acer, Inc. dmi.chassis.version: N/A dmi.modalias: dmi:bvnAcer:bvrv1.3216:bd10/27/06:svnAcer,inc.:pnAspire3680:pvrNotApplicable:rvnAcer,Inc.:rnPrespa1:rvrNotApplicable:cvnAcer,Inc.:ct1:cvrN/A: dmi.product.name: Aspire 3680 dmi.product.version: Not Applicable dmi.sys.vendor: Acer, inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1219548/+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
