From KVM
m (drop irrelevant command-line arguments in the example, to show only net-related ones)
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As of September 2010, vhost is not included in any released tarballs, so you need the git version.
 
As of September 2010, vhost is not included in any released tarballs, so you need the git version.
  
Vhost provides better latency (10% less than e1000 on my system) and greater throughput (8x the normal virtio, around 7~8 Gigabytes/sec here) for network.
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[[VhostNet]] provides better latency (10% less than e1000 on my system) and greater throughput (8x the normal virtio, around 7~8 Gigabits/sec here) for network.
  
 
=== Obtaining the code ===
 
=== Obtaining the code ===
  
* git clone git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git
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'''You need the at least qemu-kvm-0.13.0''' (http://sourceforge.net/projects/kvm/files/qemu-kvm/)
* git checkout refs/remotes/origin/stable-0.13
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* cd kvm
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* compile as usual
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=== kernel requirements ===
 
=== kernel requirements ===
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=== example command line ===
 
=== example command line ===
 
To start a guest with vhost:
 
To start a guest with vhost:
* /usr/bin/kvm -netdev type=tap,id=guest0,script=kvm-ifup,vhost=on -device virtio-net-pci,netdev=guest0,mac=00:16:3e:00:00:01 ..other options..
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* kvm -netdev type=tap,id=guest0,script=kvm-ifup,'''vhost=on''' -device virtio-net-pci,netdev=guest0,mac=''ma:c:a:dd:re:ss'' ..''other options''..
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=== Caveats ===
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Some DHCP clients have problems with this implementation, more [http://www.spinics.net/lists/kvm/msg37660.html details here].

Latest revision as of 10:24, 8 March 2011

As of September 2010, vhost is not included in any released tarballs, so you need the git version.

VhostNet provides better latency (10% less than e1000 on my system) and greater throughput (8x the normal virtio, around 7~8 Gigabits/sec here) for network.

Obtaining the code

You need the at least qemu-kvm-0.13.0 (http://sourceforge.net/projects/kvm/files/qemu-kvm/)

kernel requirements

On the host you need a kernel with CONFIG_VHOST_NET=y and in the guest you need a kernel with CONFIG_PCI_MSI=y

example command line

To start a guest with vhost:

  • kvm -netdev type=tap,id=guest0,script=kvm-ifup,vhost=on -device virtio-net-pci,netdev=guest0,mac=ma:c:a:dd:re:ss ..other options..

Caveats

Some DHCP clients have problems with this implementation, more details here.