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[Bug 1236607] Re: cifs.ko should default to CIFSMaxBufSize=65535


Yes, setting CIFSMaxBufSize=65535 produced a jump from ~40-50mb/s to
70-80mb/s when doing dd or rsync -W copies to a CIFS mounted share.
Setting it to the maximum worked fine too, but I've only tested with
Samba on Linux - I don't know what the performance implication would be
with a Windows client.

GVFS defaults the window size to 65535 (well, 65534 due to an issue they
found there somehow) though it has other performance issues but it may
explain reports of CIFS mounts being a lot slower then GVFS for some

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  cifs.ko should default to CIFSMaxBufSize=65535

Status in “linux” package in Ubuntu:
  In Progress
Status in “linux” source package in Saucy:
  In Progress

Bug description:
  Win 7 and other clients can handle a CIFS max buffer size of 64k, and
  default to this value when talking to Windows or Linux SMB servers.
  The practical effect of this is drag-drop file operations in Windows
  can run at near gigabit speeds (80-90mb/s over a gigabit LAN) even
  when talking to a Linux Samba server.

  The 'cifs' filesystem on the other hand struggles to achieve this by
  default because it's buffer size is constrained to just 16k. Boosting
  the buffer size with a modprobe.d options file like so:

  options cifs CIFSMaxBufSize=65536

  or even:

  options cifs CIFSMaxBufSize=130048

  produces a speed up in file operations (as measured with rsync -W
  between two mountpoints, or dd | pv | dd) which is on par with the
  speed achieved by Windows - taking cifs from averaging 40-50 mb/s on
  my machine, to the 80-90 mb/s the same machine running Windows (and
  talking to a Linux samba server) can achieve.

  There doesn't seem to be any real downside to this in the common desktop use case in the modern age (memory is not a constraint), so shipping a modprobe.d cifs.conf file seems like a sensible way to close the perceived gap in user experience.
  ApportVersion: 2.9.2-0ubuntu8.3
  Architecture: amd64
   /dev/snd/controlC1:  will       3215 F.... pulseaudio
   /dev/snd/controlC2:  will       3215 F.... pulseaudio
   /dev/snd/controlC0:  will       3215 F.... pulseaudio
  CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
  DistroRelease: LinuxMint 15
  HibernationDevice: RESUME=UUID=0f40c3a5-e01e-4300-9363-384d60c1f893
  InstallationDate: Installed on 2012-07-12 (452 days ago)
  InstallationMedia: Linux Mint 13 "Maya" - Release amd64 (20120520)
   eth0      no wireless extensions.
   lo        no wireless extensions.
  MachineType: Gigabyte Technology Co., Ltd. P67A-UD3P-B3
  MarkForUpload: True
  NonfreeKernelModules: zfs zunicode zavl zcommon znvpair
  Package: linux [origin: Ubuntu]
  PackageArchitecture: amd64
  ProcFB: 0 radeondrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/ROOT/mint-13@/boot/vmlinuz-3.8.0-31-generic root=/dev/sdg3 ro loglevel=7 boot=zfs rpool=ssdpool
  ProcVersionSignature: Ubuntu 3.8.0-31.46-generic
   linux-restricted-modules-3.8.0-31-generic N/A
   linux-backports-modules-3.8.0-31-generic  N/A
   linux-firmware                            1.106
   3: hci0: Bluetooth
   	Soft blocked: no
   	Hard blocked: no
  Tags: third-party-packages olivia
  Uname: Linux 3.8.0-31-generic x86_64
  UnreportableReason: This is not an official LinuxMint package. Please remove any third party package and try again.
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm cdrom debian-tor dialout dip libvirtd lpadmin plugdev sambashare sudo vboxusers wireshark
  dmi.bios.date: 03/21/2012
  dmi.bios.vendor: Award Software International, Inc.
  dmi.bios.version: F9
  dmi.board.name: P67A-UD3P-B3
  dmi.board.vendor: Gigabyte Technology Co., Ltd.
  dmi.chassis.type: 3
  dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
  dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF9:bd03/21/2012:svnGigabyteTechnologyCo.,Ltd.:pnP67A-UD3P-B3:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnP67A-UD3P-B3:rvr:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
  dmi.product.name: P67A-UD3P-B3
  dmi.sys.vendor: Gigabyte Technology Co., Ltd.

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