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[Dave Johansen <davejohansen@xxxxxxxxx>]

I no longer have access to this hardware to get the full computer model,
but the referenced test programs should be able to reproduce the issue
on most, if not all machines (it's worked on everyone I've tried it on
to date).

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https://bugs.launchpad.net/bugs/1058864

Title:
  Poor mutex and semaphore performance

Status in “linux” package in Ubuntu:
  Incomplete

Bug description:
  I noticed the results of this blog post:
  http://mr-edd.co.uk/blog/sad_state_of_osx_pthread_mutex_t
  and I was curious if the same sort of issue existed with the linux kernel and if it would shed any light on Bug #1058854
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1058854

  The results don't appear to be as bad as those seen on Mac OS X, but they definitely are a lot poorer than I expected/hoped they would be. The code that builds on Linux is now available on that blog port and I created a git repo with the history here:
  https://github.com/daveisfera/test_mutex

  Here are the results from running it on the the same HP Pavilion dm4 that as the results from Bug #1058854:
  mutex
   1 thread  real 0m 0.514s user 0m 0.512s sys 0m 0.000s
   2 threads real 0m 4.382s user 0m 5.176s sys 0m 3.544s
   4 threads real 0m 9.953s user 0m 9.709s sys 0m22.417s
   8 threads real 0m20.984s user 0m14.973s sys 1m 8.256s
  16 threads real 0m38.725s user 0m28.426s sys 2m 5.484s

  benaphore
   1 thread  real 0m 0.324s user 0m 0.312s sys 0m 0.008s
   2 threads real 0m 6.372s user 0m 6.380s sys 0m 5.572s
   4 threads real 0m17.820s user 0m12.273s sys 0m42.495s
   8 threads real 0m40.266s user 0m25.626s sys 2m14.400s
  16 threads real 1m40.090s user 0m52.939s sys 5m45.802s

  mutex2
   1 thread  real 0m 0.325s user 0m 0.320s sys 0m 0.004s
   2 threads real 0m 0.730s user 0m 0.816s sys 0m 0.384s
   4 threads real 0m 2.328s user 0m 3.388s sys 0m 5.704s
   8 threads real 0m 4.096s user 0m 5.328s sys 0m10.705s
  16 threads real 0m 7.584s user 0m 9.609s sys 0m20.401s
  --- 
  AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
  ApportVersion: 2.0.1-0ubuntu13
  Architecture: amd64
  ArecordDevices:
   **** List of CAPTURE Hardware Devices ****
   card 0: PCH [HDA Intel PCH], device 0: STAC92xx Analog [STAC92xx Analog]
     Subdevices: 1/1
     Subdevice #0: subdevice #0
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  dlj        1876 F.... pulseaudio
  Card0.Amixer.info:
   Card hw:0 'PCH'/'HDA Intel PCH at 0xc0800000 irq 50'
     Mixer name	: 'Intel CougarPoint HDMI'
     Components	: 'HDA:111d76e0,103c1793,00100102 HDA:80862805,103c1793,00100000'
     Controls      : 22
     Simple ctrls  : 10
  DistroRelease: Ubuntu 12.04
  InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
  MachineType: Hewlett-Packard HP Pavilion dm4 Notebook PC
  Package: linux (not installed)
  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-31-generic root=UUID=162256F02256D479 loop=/hostname/disks/root.disk ro quiet splash vt.handoff=7
  ProcVersionSignature: Ubuntu 3.2.0-31.50-generic 3.2.28
  RelatedPackageVersions:
   linux-restricted-modules-3.2.0-31-generic N/A
   linux-backports-modules-3.2.0-31-generic  N/A
   linux-firmware                            1.79.1
  StagingDrivers: rts_pstor mei
  Tags:  precise running-unity staging
  Uname: Linux 3.2.0-31-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
  dmi.bios.date: 01/17/2012
  dmi.bios.vendor: Hewlett-Packard
  dmi.bios.version: F.08
  dmi.board.asset.tag: Base Board Asset Tag
  dmi.board.name: 1793
  dmi.board.vendor: Hewlett-Packard
  dmi.board.version: 41.1C
  dmi.chassis.asset.tag: Chassis Asset Tag
  dmi.chassis.type: 10
  dmi.chassis.vendor: Hewlett-Packard
  dmi.chassis.version: Chassis Version
  dmi.modalias: dmi:bvnHewlett-Packard:bvrF.08:bd01/17/2012:svnHewlett-Packard:pnHPPaviliondm4NotebookPC:pvr068E100002204710000622100:rvnHewlett-Packard:rn1793:rvr41.1C:cvnHewlett-Packard:ct10:cvrChassisVersion:
  dmi.product.name: HP Pavilion dm4 Notebook PC
  dmi.product.version: 068E100002204710000622100
  dmi.sys.vendor: Hewlett-Packard

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