Update and request from upstream: "I have looked at the dump and there is something very odd for system.slice task group where the display manager is running. system.slice->tg_load_avg is around 381697 but tg_load_avg is normally equal to Sum of system.slice[cpu]->tg_load_avg_contrib whereas Sum of system.slice[cpu]->tg_load_avg_contrib = 1013 in our case. We can have some differences because the dump of /proc/shed_debug is not atomic and some changes can happen but nothing like this difference.
The main effect of this quite high value is that the weight/prio of the sched_entity that represents system.slice in root cfs_rq is very low (lower than task with the smallest nice prio) so the system.slice task group will not get the CPU quite often compared to the user.slice task group: less than 1% for the system.slice where lightDM and xorg are running compared 99% for the user.slice where the stress tasks are running. This is confirmed by the se->avg.util_avg value of the task groups which reflect how much time each task group is effectively running on a CPU: system.slice[CPU3].se->avg.util_avg = 8 whereas user.slice[CPU3].se->avg.util_avg = 991 This difference of weight/priority explains why the system becomes unresponsive. For now, I can't explain is why system.slice->tg_load_avg = 381697 whereas is should be around 1013 and how the patch can generate this situation. Is it possible to have a dump of /proc/sched_debug before starting stress command ? to check if the problem is there from the beginning but not seen because not overloaded. Or if it the problem comes when user starts to load the system" -- 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/1627108 Title: X1Carbon comes to a crawl during high CPU usage tasks Status in linux package in Ubuntu: In Progress Status in linux source package in Yakkety: In Progress Bug description: My X1Carbon becomes quite laggy, the cursor hangs for a few seconds and then resumes while my system is compiling some code, or lets says PyCharm is indexing things or Android Studio is compiling some code. I was using 4.4 on Xenial a few days ago and everything was working just fine. Installed Yakkety and this issue happens. TEST CASE: `stress -c 4` <-- that results in system slowness. I will downgrade the kernel and see if that mitigates the issue. ProblemType: Bug DistroRelease: Ubuntu 16.10 Package: linux-image-4.8.0-15-generic 4.8.0-15.16 ProcVersionSignature: Ubuntu 4.8.0-15.16-generic 4.8.0-rc7 Uname: Linux 4.8.0-15-generic x86_64 ApportVersion: 2.20.3-0ubuntu7 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/pcmC1D0p: om26er 3390 F...m pulseaudio /dev/snd/controlC1: om26er 3390 F.... pulseaudio /dev/snd/controlC0: om26er 3390 F.... pulseaudio CurrentDesktop: Unity Date: Fri Sep 23 21:40:34 2016 HibernationDevice: RESUME=UUID=a92c85ab-cca3-4afc-abf1-3516f193129e InstallationDate: Installed on 2016-09-21 (1 days ago) InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Alpha amd64 (20160921) MachineType: LENOVO 20BSCTO1WW ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.8.0-15-generic.efi.signed root=UUID=01b0a4a0-d791-46e8-a212-1f769cff3a4b ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-4.8.0-15-generic N/A linux-backports-modules-4.8.0-15-generic N/A linux-firmware 1.161 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 08/13/2015 dmi.bios.vendor: LENOVO dmi.bios.version: N14ET32W (1.10 ) dmi.board.asset.tag: Not Available dmi.board.name: 20BSCTO1WW dmi.board.vendor: LENOVO dmi.board.version: SDK0E50510 WIN dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrN14ET32W(1.10):bd08/13/2015:svnLENOVO:pn20BSCTO1WW:pvrThinkPadX1Carbon3rd:rvnLENOVO:rn20BSCTO1WW:rvrSDK0E50510WIN:cvnLENOVO:ct10:cvrNone: dmi.product.name: 20BSCTO1WW dmi.product.version: ThinkPad X1 Carbon 3rd dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1627108/+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
