Is it normal that C-states percentages reported by i7z don't sum up to 100%, but exceed it? Under load, I frequently get C0% close to 99%, but at the same time Halt is at about 40-60%. Also when C0 is >90, the frequency of cores goes DOWN. This looks totally reversed to me.
-- 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/1797802 Title: Erratic behavior of intel pstate CPU frequency control Status in linux package in Ubuntu: Incomplete 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/system/cpu/intel_pstate/min_perf_pct echo 80 > /sys/devices/system/cpu/intel_pstate/max_perf_pct 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-4.18.0-10-generic 4.18.0-10.11 ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12 Uname: Linux 4.18.0-10-generic x86_64 ApportVersion: 2.20.10-0ubuntu13 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: pkolaczk 3281 F.... pulseaudio /dev/snd/pcmC0D0c: pkolaczk 3281 F...m pulseaudio CurrentDesktop: ubuntu:GNOME Date: Sun Oct 14 22:16:50 2018 DistributionChannelDescriptor: # This is a distribution channel descriptor # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-somerville-xenial-amd64-20160624-2 HibernationDevice: RESUME=UUID=4836842e-0116-43c4-98b4-7a56427f81f1 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-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=pl_PL.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.18.0-10-generic root=UUID=7f76b1f0-8fef-41cc-86a2-99e554cb4d40 ro acpi_rev_override quiet splash iwlwifi.power_save=1 crashkernel=384M-:128M crashkernel=384M-:128M vt.handoff=1 RelatedPackageVersions: linux-restricted-modules-4.18.0-10-generic N/A linux-backports-modules-4.18.0-10-generic N/A 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.:bvr1.11.0:bd07/24/2018:svnDellInc.:pnPrecision5520:pvr:rvnDellInc.:rn06X96V:rvrA00:cvnDellInc.:ct10:cvr: dmi.product.family: Precision dmi.product.name: Precision 5520 dmi.product.sku: 07BF dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1797802/+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
