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[Maarten Bezemer <maarten.bezemer@xxxxxxxxx>]

The newest mainline kernel (for saucy) 3.11.0-15 does not show the
problem... So I guess it does not make sense to open a new report?

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https://bugs.launchpad.net/bugs/582145

Title:
  Virtual guests' console is unusably slow due to framebuffer usage

Status in “linux” package in Ubuntu:
  Incomplete

Bug description:
  This was also discussed in https://lists.ubuntu.com/archives/ubuntu-
  server/2010-May/004172.html

  The problem is that the console of a Ubuntu 10.04 (server) virtual
  machine/guest becomes incredibly slow and really unusable as soon as
  it starts scrolling. This is apparently due to the kernel switching on
  the console framebuffer which does not play well with the VNC-based
  console viewers of virt-manager. I have created a screencast to
  demonstrate, please find it here: https://daff.pseudoterminal.org/misc
  /console-slow.ogg

  I have experienced this using KVM and virt-manager/virt-viewer on
  Ubuntu 10.04 and Ubuntu 9.10 hosts (using the server edition, FWIW).
  Apparently it also happens with VirtualBox but I have not tested this
  myself. The only solution for the time being seems to be to blacklist
  the vga16fb module as suggested by Paul Nuffer:

      $ echo "blacklist vga16fb" | sudo tee -a /etc/modprobe.d/blacklist

  Merely adding "nomodeset" to the kernel boot options is not
  sufficient.

  I don't even know exactly to which package this bug belongs let alone
  what to do about it except force the kernel not to use a console
  framebuffer. I know Plymouth needs the framebuffer to display splash
  screens and whatnot but there should be a proper way to disable it
  when running as a virtual machine. And since the splash screen is
  disabled anyway when creating a server virtual machine there is really
  no use in a framebuffer, especially if it slows everything down to a
  crawl. So what to do?

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