Erratic behavior of CPU frequency control under load
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
thermald (Ubuntu) |
Won't Fix
|
Medium
|
Unassigned |
Bug Description
I noticed that sometimes my Ubuntu 18.10 system feels sluggish. The other times everything works fine. I don't know what triggers this weird state. Suspend / resume? Maybe.
At first I thought this was maybe just a "perception issue", but then when the sluggishness happened again, I fired up i7z and it looks that CPU frequency almost never got over ~1600 MHz, But my CPU is perfectly capable of going up to 4000 MHz!
I tried to fix it by setting
echo 80 > /sys/devices/
echo 80 > /sys/devices/
I hoped I would force the CPU into almost max performance state this way. And indeed, once I ran these commands, i7z showed steady 3100+ MHz on all cores.
Then something weird happened - when I run some mild load on the CPU, like just starting the IDE, during the startup the frequency ** dropped back to about 800-1600 MHz ** and returned to 3100 MHz after the load was gone (IDE loaded).
The CPU core temperatures shown by sensors / i7z are ok and typically at about 40-50 C when this slowdown happens, so this doesn't look like thermal throttling.
Any ideas?
ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: linux-image-
ProcVersionSign
Uname: Linux 4.18.0-10-generic x86_64
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
/dev/snd/pcmC0D0c: pkolaczk 3281 F...m pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 14 22:16:50 2018
DistributionCha
# This is a distribution channel descriptor
# For more information see http://
canonical-
HibernationDevice: RESUME=
InstallationDate: Installed on 2017-04-12 (549 days ago)
InstallationMedia: Ubuntu 16.04 "Xenial" - Build amd64 LIVE Binary 20160624-10:47
MachineType: Dell Inc. Precision 5520
ProcEnviron:
TERM=xterm-
PATH=(custom, no user)
XDG_RUNTIME_
LANG=pl_PL.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=
RelatedPackageV
linux-
linux-
linux-firmware 1.175
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/24/2018
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.11.0
dmi.board.name: 06X96V
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.
dmi.product.family: Precision
dmi.product.name: Precision 5520
dmi.product.sku: 07BF
dmi.sys.vendor: Dell Inc.
Changed in linux (Ubuntu): | |
status: | Incomplete → Confirmed |
Changed in linux (Ubuntu): | |
importance: | Undecided → Medium |
status: | Confirmed → Incomplete |
status: | Incomplete → Triaged |
summary: |
- Erratic behavior of intel pstate CPU frequency control + Erratic behavior of CPU frequency control under load |
affects: | linux (Ubuntu) → thermald (Ubuntu) |
Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
Would it be possible for you to test the latest upstream kernel? Refer to https:/ /wiki.ubuntu. com/KernelMainl ineBuilds . Please test the latest v4.19 kernel[0].
If this bug is fixed in the mainline kernel, please add the following tag 'kernel- fixed-upstream' .
If the mainline kernel does not fix this bug, please add the tag: 'kernel- bug-exists- upstream' .
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".
Thanks in advance.
[0] http:// kernel. ubuntu. com/~kernel- ppa/mainline/ v4.19-rc7/