Why does a Ubuntu guest in VirtualBox run very, very slowly?

I'm using currently Ubuntu 12.04 LTS as a host machine, and I've virtualized three machines:

• a Xubuntu 12.04 guest
• a Windows 7 guest
• a Ubuntu 12.10 guest

All the guests have the same VirtualBox default settings, but Ubuntu 12.10 is slower!

The installation took 1h 40 min! (Normally, it takes 40 minutes.) Now it is impossible to use it, and all operations are very, very slow.

I'm using VirtualBox version 4.2.4.

Any ideas?

Why is it slow? And how can I make it faster?

Solution 1:

Ubuntu 12.10 no longer includes Unity 2D, which was implemented for platforms that can't provide 3D acceleration. Instead, Ubuntu 12.10 has Unity run under LLVM, making code intended for the GPU run on the CPU. It is much slower than using the GPU.

To check if your Ubuntu 12.10 guest is using 3D acceleration, run this command:

$ /usr/lib/nux/unity_support_test -p
Not software rendered:    no
Not blacklisted:          yes
GLX fbconfig:             yes
GLX texture from pixmap:  yes
GL npot or rect textures: yes
GL vertex program:        yes
GL fragment program:      yes
GL vertex buffer object:  yes
GL framebuffer object:    yes
GL version is 1.4+:       yes

Unity 3D supported:       no

As you can see, "Not software rendered" and "Unity 3D supported" both return "no" in this example, which means Unity is using slow LLVMpipe.

How to enable 3D acceleration (VirtualBox 4.2.x only)

These instructions are intended for VirtualBox 4.2.4 or 4.2.6, installed from VirtualBox's website, not from Ubuntu's repo. Future versions of VirtualBox may fix this problem automatically, or may need a different workaround.

1. Install VirtualBox Oracle VM VirtualBox Extension Pack.
2. Create a VirtualBox instance and install Ubuntu 12.10 on it.

3. Install some required packages for the guest additions:

   sudo apt-get install linux-headers-$(uname -r) build-essential
   

4. Install the guest additions by clicking Devices, Install Guest Additions and running this command from the CD-ROM's directory:

   sudo ./VBoxLinuxAdditions.run
   

5. Add the vboxvideo driver to the instance by running:

   sudo bash -c 'echo vboxvideo >> /etc/modules'
   

6. Shutdown the VirtualBox instance.
7. Open the settings of the Virtualbox instance, navigate to "Display", and tick "Enable 3D acceleration".

8. Boot your Ubuntu 12.10 guest, and check that 3D acceleration is working by running:

   /usr/lib/nux/unity_support_test -p
   

If windows seem to disppear, install CompizConfig Settings Manager and disable Framebuffer Object (FBO) in the OpenGL section:

1. Install the CompizConfig Settings Manager:

   sudo apt-get install compizconfig-settings-manager
   

2. Run the CompizConfig Settings Manager:

   ccsm
   

3. Select the OpenGL section and then untick the Framebuffer Object option. If this fixes the issue it should be immediately visible. No reboot is required.

Solution 2:

I have heard it has something to do with the fact they removed Unity 2D, or somehow the switch to 3D Unity only slows down the VM performance due to the heavy reliance on the CPU handling more that it used to have to. The Linux Outlaws podcast talked about it a bit, but I forget the episode.

Update: The problem is with Virtualbox Guest Additions not providing 3D acceleration in 12.10. See Ubuntu 12.10 unable to use 3D acceleration. Fails to build DRM.