kernel-packages team mailing list archive

[Denis Nikolaenko <1107150@xxxxxxxxxxxxxxxxxx>]

The problem is still an issue on i686 PAE kernel in raring.
Got a Lenovo W520 Laptop with 24GiB of RAM. "apt-get update" takes several minutes.
However I found a workaround as alternative to removing the memory physically.
Add "mem=0x200000000" kernel boot parameter in /etc/default/grub in run update-grub.
This will limit memory usage to first 8GiB.
After that even the boot became significantly faster.
I found that without the workaround, the value in /proc/sys/vm/dirty_bytes is always zero.
I believe the write caching becomes completely disabled in PAE kernel running in machine with a lot of RAM.

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https://bugs.launchpad.net/bugs/1107150

Title:
  B75 Chipset I/O Problems

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  I built a new system and installed Ubuntu 12.10. The system has the
  following specifications:

  Samsung 840 Pro 128 GB 
  Gigabyte P75-D3
  Intel i7 3770
  32 GB Ram
  Western Digital 1 TB Black (mounted as /home)
  Western Digital 3 TB Green (mounted as /media/data_drive)

  The initial Ubuntu 12.10 install took almost 6 hours as transfer rates
  were very slow. After reboot everything appeared very fast. However
  when I did an "apt-get update" the download took 20 seconds and the
  processing of lists took 19 minutes.

  I had 12.10 installed on another computer which was working great
  (older Althon system) so I installed the drive and tested the new
  machine. It suffered the same performance problems.

  I installed Windows 7 and performed speeds tests, it reported great
  results.

  I installed 12.04 onto the 1 TB drive and it did not suffer the same
  performance problems. Everything ran great.

  I then upgraded 12.10 to 13.04 (January 27, 2013) and it too suffered
  from the performance issue.

  It appears that a change between 12.04 to 12.10 impacts AHCI based
  systems specifically running the Intel B75 chipset. I am not certain
  but I think that either the motherboard is misrepresenting something
  (that 12.04 ignores but it impacts 12.10) or the kernel is not
  detecting the system correctly.

  I created a couple of pastebins with data collected:

  12.10 Install: http://pastebin.ubuntu.com/1561660/
  12.04 Live Disk (was checked against installed version and data is mostly the same): http://paste.ubuntu.com/1565140/

  I have a thread on the ubuntu forums that may provide additional
  details: http://ubuntuforums.org/showthread.php?t=2104709

  I also started an e-mail thread to the ubuntu-users mailing list:
  http://ubuntu.5.n6.nabble.com/Seeking-Help-td5010422.html

  I have done a lot of troubleshooting and I feel that the problem must
  either be the kernel or the bios misrepresenting information. In
  either case I am stuck without any idea of where to go next with the
  debuging and diagnoses path.

  If any additional information needs to be collected, please let me know and I will work to assist.
  --- 
  AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
  ApportVersion: 2.0.1-0ubuntu17.1
  Architecture: i386
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC1:  bakers     1729 F.... pulseaudio
   /dev/snd/controlC0:  bakers     1729 F.... pulseaudio
  CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
  Card0.Amixer.info:
   Card hw:0 'PCH'/'HDA Intel PCH at 0xf7110000 irq 45'
     Mixer name	: 'Realtek ALC887-VD'
     Components	: 'HDA:10ec0887,1458a002,00100302'
     Controls      : 39
     Simple ctrls  : 20
  Card1.Amixer.info:
   Card hw:1 'NVidia'/'HDA NVidia at 0xf7080000 irq 17'
     Mixer name	: 'Nvidia GPU 42 HDMI/DP'
     Components	: 'HDA:10de0042,14583553,00100100'
     Controls      : 18
     Simple ctrls  : 3
  DistroRelease: Ubuntu 12.04
  IwConfig:
   lo        no wireless extensions.
   
   eth0      no wireless extensions.
  MachineType: Gigabyte Technology Co., Ltd. To be filled by O.E.M.
  MarkForUpload: True
  NonfreeKernelModules: nvidia
  Package: linux (not installed)
  ProcEnviron:
   LANGUAGE=en_CA:en
   TERM=xterm
   PATH=(custom, no user)
   LANG=en_CA.UTF-8
   SHELL=/bin/bash
  ProcFB:
   
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-36-generic-pae root=UUID=4f30252c-fa56-4d53-be78-117cddab55f4 ro quiet splash
  ProcVersionSignature: Ubuntu 3.2.0-36.57-generic-pae 3.2.35
  RelatedPackageVersions:
   linux-restricted-modules-3.2.0-36-generic-pae N/A
   linux-backports-modules-3.2.0-36-generic-pae  N/A
   linux-firmware                                1.79.1
  RfKill:
   
  StagingDrivers: mei
  Tags:  precise running-unity staging
  Uname: Linux 3.2.0-36-generic-pae i686
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
  dmi.bios.date: 08/21/2012
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: F9
  dmi.board.asset.tag: To be filled by O.E.M.
  dmi.board.name: P75-D3
  dmi.board.vendor: Gigabyte Technology Co., Ltd.
  dmi.board.version: x.x
  dmi.chassis.asset.tag: To Be Filled By O.E.M.
  dmi.chassis.type: 3
  dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
  dmi.chassis.version: To Be Filled By O.E.M.
  dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF9:bd08/21/2012:svnGigabyteTechnologyCo.,Ltd.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnGigabyteTechnologyCo.,Ltd.:rnP75-D3:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvrToBeFilledByO.E.M.:
  dmi.product.name: To be filled by O.E.M.
  dmi.product.version: To be filled by O.E.M.
  dmi.sys.vendor: Gigabyte Technology Co., Ltd.

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