From KVM
m (show the important option in bold)
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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..
+
* /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..
  
 
=== Caveats ===
 
=== Caveats ===
 
Some DHCP clients have problems with this implementation, more [http://www.spinics.net/lists/kvm/msg37660.html details here].
 
Some DHCP clients have problems with this implementation, more [http://www.spinics.net/lists/kvm/msg37660.html details here].

Revision as of 10:11, 24 February 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:

  • /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..

Caveats

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