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[William Katcher <katcherw@xxxxxxxxx>]

As an experiment, I removed the powerclamp driver and monitored the temp
sensors. The GPU never got close to high. The CPU has two thresholds,
high of 86 C and critical of 100 C. With the powerclamp driver, the idle
injection always kicked in at 86. Without, the temp stayed at around 99
C, never ever going above 100. So you look like you're right, the CPU
must be throttling itself. The PC behaved as it used to, no noticeable
slowdown whatsoever.

I will now blacklist the driver and have my PC like it was before.

I recommend that the powerclamp driver be disabled by default, as there
must be many people who are experiencing unnecessary and dramatic
performance reduction, and have no clue what is causing it.

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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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