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"
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X1Carbon comes to a crawl during high CPU usage tasks
Status in linux package in Ubuntu:
Status in linux source package in Yakkety:
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.
`stress -c 4` <-- that results in system slowness.
I will downgrade the kernel and see if that mitigates the issue.
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
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
Date: Fri Sep 23 21:40:34 2016
InstallationDate: Installed on 2016-09-21 (1 days ago)
InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Alpha amd64 (20160921)
MachineType: LENOVO 20BSCTO1WW
ProcFB: 0 inteldrmfb
root=UUID=01b0a4a0-d791-46e8-a212-1f769cff3a4b ro quiet splash vt.handoff=7
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.version: N14ET32W (1.10 )
dmi.board.asset.tag: Not Available
dmi.board.version: SDK0E50510 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.product.version: ThinkPad X1 Carbon 3rd
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