kernel-packages team mailing list archive

[Doug Smythies <1497520@xxxxxxxxxxxxxxxxxx>]

To the best of my knowledge, this specific (resume from suspend,
intel_pstate, performance mode) issue has been fixed in the upstream
kernel. However, I never understood this issue to be specific to battery
mode, an interesting twist.

Note that there are other issues, and sometimes it is hard to separate
the issues and they tend to cross contaminate these bug reports.

See also: 
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1484587/comments/5

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https://bugs.launchpad.net/bugs/1497520

Title:
  Slow performance after resuming from/on battery (CPUs do not scale
  above 800MHz)

Status in linux package in Ubuntu:
  Confirmed

Bug description:
  I have noticed slow performance after resuming from STR on battery.

  I can not trigger this always, but it seems to be related to
  suspending and resuming while on battery.

  The CPU scaling governors look like this then:

  % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
  powersave
  performance
  performance
  performance

  % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver 
  intel_pstate
  intel_pstate
  intel_pstate
  intel_pstate

  % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
  3200000
  3200000
  3200000
  3200000

  When watching the current CPU frequencies, it can be seen that they
  don't go above 800000 ('watch grep \"cpu MHz\" /proc/cpuinfo').

  I cannot see why they are limited to 800000.

  It looks like https://bugzilla.kernel.org/show_bug.cgi?id=61241, but
  /sys/devices/system/cpu/intel_pstate/max_perf_pct is at 100.

  Just writing the same setting for cpu0 again fixes it, and all CPUs
  will be scaled above 800MHz again:

  % echo powersave | sudo tee
  /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

  ProblemType: Bug
  DistroRelease: Ubuntu 15.04
  Package: linux-image-3.19.0-28-generic 3.19.0-28.30
  ProcVersionSignature: Ubuntu 3.19.0-28.30-generic 3.19.8-ckt5
  Uname: Linux 3.19.0-28-generic x86_64
  ApportVersion: 2.17.2-0ubuntu1.4
  Architecture: amd64
  CurrentDesktop: Unity
  Date: Sat Sep 19 10:39:02 2015
  HibernationDevice: RESUME=UUID=d39463f5-889e-42ba-a729-f3f442f0c8dd
  InstallationDate: Installed on 2012-05-28 (1208 days ago)
  InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
  MachineType: LENOVO 42992PG
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.19.0-28-generic root=/dev/mapper/vg0-rootlv ro quiet splash
  RelatedPackageVersions:
   linux-restricted-modules-3.19.0-28-generic N/A
   linux-backports-modules-3.19.0-28-generic  N/A
   linux-firmware                             1.143.3
  SourcePackage: linux
  UpgradeStatus: Upgraded to vivid on 2015-05-14 (127 days ago)
  dmi.bios.date: 05/14/2015
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 8DET70WW (1.40 )
  dmi.board.asset.tag: Not Available
  dmi.board.name: 42992PG
  dmi.board.vendor: LENOVO
  dmi.board.version: Not Available
  dmi.chassis.asset.tag: No Asset Information
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Not Available
  dmi.modalias: dmi:bvnLENOVO:bvr8DET70WW(1.40):bd05/14/2015:svnLENOVO:pn42992PG:pvrThinkPadX220Tablet:rvnLENOVO:rn42992PG:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
  dmi.product.name: 42992PG
  dmi.product.version: ThinkPad X220 Tablet
  dmi.sys.vendor: LENOVO

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