kernel-packages team mailing list archive

[Ilya Murav'jov <muravjov.il@xxxxxxxxx>]

Hi all,

After compiling kernels for a while I found out why the Fedora's kernel works for me: it is built without PAE support.
I've bisected Ubuntu' and Fedora's .config files and it turnes out that CONFIG_HIGHMEM4G=y "fixes" my issue ;) .

After that I rebooted my machine with default Ubuntu kernel (PAE) and
16Gb RAM, not 32GB, and it also "fixed" my issue ;)

After that I built a kernel with PAE, 32GB but with CONFIG_VMSPLIT_1G=y
,  and again, it really fixed my issue (but it is incompatible with
binary drivers, see documentation; and my fglrx didn't work).

To wit: Linux kernel doesn't work well with 32bit, PAE and >=32 Gb RAM. (I even saw such statemets somewhere on the Net.)
Am I right? If so, I think Ubuntu documentation should state it explicitly.


** Summary changed:

- IO limit 1.2 MB/s for 32bit ubuntu (ACPI issues)
+ IO limit 1.2 MB/s for 32bit ubuntu (PAE, 32 Gb RAM)

-- 
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https://bugs.launchpad.net/bugs/1264707

Title:
  IO limit 1.2 MB/s for 32bit ubuntu (PAE, 32 Gb RAM)

Status in “linux” package in Ubuntu:
  Incomplete

Bug description:
  I recently installed a new motherboard Asus M5A99FX PRO R2.0 and found out that IO speed is very low; i.e.  the dd command output:
  dd if=/dev/zero of=/tmp/output bs=8k count=1000k
  ^C13885+0 records in
  13885+0 records out
  113745920 bytes (114 MB) copied, 99.6639 s, 1.1 MB/s

  This issue is reproducing with my new SSD (with ext4), my USB drives
  and my hard disk (with ext4) from Ubuntu i386, 13.04 and 13.10. Such a
  speed is not ok, awfully slow. When I run two or more the same dd
  commands simultaneously,  I have 1,2 Mb/s for every process.

  WORKAROUNDs: 
  - turn off ACPI services, see more at https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1264707/comments/18
  - Use the amd64 version

  ProblemType: Bug
  DistroRelease: Ubuntu 13.10
  Package: linux-image-3.11.0-12-generic 3.11.0-12.19
  ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3
  Uname: Linux 3.11.0-12-generic i686
  ApportVersion: 2.12.5-0ubuntu2
  Architecture: i386
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC2:  ubuntu     4507 F.... pulseaudio
   /dev/snd/controlC1:  ubuntu     4507 F.... pulseaudio
   /dev/snd/controlC0:  ubuntu     4507 F.... pulseaudio
  CasperVersion: 1.336ubuntu1
  Date: Sat Dec 28 15:56:33 2013
  IwConfig:
   lo        no wireless extensions.

   eth0      no wireless extensions.
  LiveMediaBuild: Ubuntu 13.10 "Saucy Salamander" - Release i386 (20131016.1)
  MachineType: To be filled by O.E.M. To be filled by O.E.M.
  MarkForUpload: True
  ProcEnviron:
   LANGUAGE=en_US
   TERM=xterm
   PATH=(custom, no user)
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB: 0 radeondrmfb
  ProcKernelCmdLine: noprompt cdrom-detect/try-usb=true persistent file=/cdrom/preseed/hostname.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity
  PulseList:
   Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied
   No PulseAudio daemon running, or not running as session daemon.
  RelatedPackageVersions:
   linux-restricted-modules-3.11.0-12-generic N/A
   linux-backports-modules-3.11.0-12-generic  N/A
   linux-firmware                             1.116
  RfKill:

  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 04/10/2013
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: 1708
  dmi.board.asset.tag: To be filled by O.E.M.
  dmi.board.name: M5A99FX PRO R2.0
  dmi.board.vendor: ASUSTeK COMPUTER INC.
  dmi.board.version: Rev 1.xx
  dmi.chassis.asset.tag: To Be Filled By O.E.M.
  dmi.chassis.type: 3
  dmi.chassis.vendor: To Be Filled By O.E.M.
  dmi.chassis.version: To Be Filled By O.E.M.
  dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1708:bd04/10/2013:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnASUSTeKCOMPUTERINC.:rnM5A99FXPROR2.0:rvrRev1.xx:cvnToBeFilledByO.E.M.: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: To be filled by O.E.M.

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