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[William Katcher <katcherw@xxxxxxxxx>]

I found a workaround by rmmod intel_powerclamp. This removed the
kidle_inject threads and the speed was returned to normal.

However, I looked at my CPU temperature, and it was 87 deg C, over the
high threshold. It is possible that the idle injection is a new kernel
feature that is kicking in to protect my CPU from overheating. Perhaps
in older kernels I didn't have any protection or there was a different
mechanism. Or perhaps something in the new kernel is causing the CPUs to
run hot.

I suppose this bug could be closed, since it is possible that the
symptom is actually a feature.

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https://bugs.launchpad.net/bugs/1389077

Title:
  [HP ProBook 4530s] Intel Powerclamp is Slowing CPU

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  I upgraded from KUbuntu 14.04 to 14.10. Immediately, while playing
  minecraft with my daughter, I noticed the game was running very
  slowly. Even after closing the game, my web browsing slowed to a
  crawl.

  Looking at the processes in top, I noticed there were 4 tasks called
  kidle_inject running at 50% CPU each. After spending a long time
  figuring out what caused this, I found out this is caused by the Intel
  Powerclamp driver. I never did anything to enable this, and haven't
  observed this slowdown before the upgrade.

  I found the powerclamp driver in the
  /sys/class/thermal/cooling_device5 directory:

  root@bkat-HP-ProBook-4530s:/sys/class/thermal/cooling_device5# cat type 
  intel_powerclamp
  root@bkat-HP-ProBook-4530s:/sys/class/thermal/cooling_device5# cat cur_state 
  -1
  root@bkat-HP-ProBook-4530s:/sys/class/thermal/cooling_device5# cat max_state 
  50

  I tried to echo 0 to cur_state, but it still reported -1 when I catted
  the value.

  There seems to be no obvious way to disable this, and this should not
  have been enabled in the first place.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.10
  Package: linux-image-3.16.0-24-generic 3.16.0-24.32
  ProcVersionSignature: Ubuntu 3.16.0-24.32-generic 3.16.4
  Uname: Linux 3.16.0-24-generic x86_64
  ApportVersion: 2.14.7-0ubuntu8
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  bkat       2780 F.... pulseaudio
  CurrentDesktop: KDE
  Date: Mon Nov  3 23:16:04 2014
  HibernationDevice: RESUME=UUID=35e1d874-a3bd-4227-acab-16f3e929d993
  InstallationDate: Installed on 2012-04-22 (925 days ago)
  InstallationMedia: Kubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
  MachineType: Hewlett-Packard HP ProBook 4530s
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-24-generic root=UUID=743f1686-bfe7-4e32-911d-5371633ccec8 ro quiet splash vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.16.0-24-generic N/A
   linux-backports-modules-3.16.0-24-generic  N/A
   linux-firmware                             1.138
  SourcePackage: linux
  UpgradeStatus: Upgraded to utopic on 2014-11-03 (0 days ago)
  dmi.bios.date: 05/13/2011
  dmi.bios.vendor: Hewlett-Packard
  dmi.bios.version: 68SRR Ver. F.09
  dmi.board.name: 167C
  dmi.board.vendor: Hewlett-Packard
  dmi.board.version: KBC Version 22.1A
  dmi.chassis.asset.tag: CNU1284V1X
  dmi.chassis.type: 10
  dmi.chassis.vendor: Hewlett-Packard
  dmi.modalias: dmi:bvnHewlett-Packard:bvr68SRRVer.F.09:bd05/13/2011:svnHewlett-Packard:pnHPProBook4530s:pvrA0001D02:rvnHewlett-Packard:rn167C:rvrKBCVersion22.1A:cvnHewlett-Packard:ct10:cvr:
  dmi.product.name: HP ProBook 4530s
  dmi.product.version: A0001D02
  dmi.sys.vendor: Hewlett-Packard

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