[libvirt-users] Network speed between two guests on same host.

[Patrick Pichon]

Have a look if vhost_net is loaded on the guest and if not load it with modeprobe vhost_net

Last when doing your lab perf test are you sure that you are not penalised by disk io either in input or outputs 

Envoyé de mon iPhone

> Le 29 févr. 2016 à 17:13, Dominique Ramaekers <dominique.ramaekers at cometal.be> a écrit :
> 
> Hi,
> 
> I've got two hosts. Most of my guests are Windows systems. I'm using LANBench to test network performance.
> 
> 1) From an physical PC to a guest (it doesn't matter on which host), I get almost 1Gb/s. They are connected through a 1Gb/s swich => very good!
> 
> 2) From a guest on one host to a guest on the other host => plusminus 1Gb/s => Okay!
> 
> 3) Between two guests on the same host => plusminus 230Mb/s ???
> 
> The guests have network over a bridged interface, so I tried the same test over a NAT interface => The same 230Mb/s...
> 
> Is there a way to tweak connection speeds between two guest running on the same host?
> 
> Thanks in advance...
> 
> An piece of the xml dump of one of the guests:
> <domain type='kvm' id='17'>
>  <name>PCVIRTdra</name>
>  <uuid>925e4f9b-2c27-406d-bdd9-f3e0b44f28bb</uuid>
>  <title>PCVIRTdra - PC voor dra</title>
>  <description></description>
>  <memory unit='KiB'>2097152</memory>
>  <currentMemory unit='KiB'>2097152</currentMemory>
>  <memoryBacking>
>    <hugepages/>
>  </memoryBacking>
>  <vcpu placement='static'>8</vcpu>
>  <resource>
>    <partition>/machine</partition>
>  </resource>
>  <os>
>    <type arch='x86_64' machine='pc-i440fx-utopic'>hvm</type>
>    <bootmenu enable='yes'/>
>  </os>
>  <features>
>    <acpi/>
>    <apic/>
>    <hyperv>
>      <relaxed state='on'/>
>      <vapic state='on'/>
>      <spinlocks state='on' retries='8191'/>
>    </hyperv>
>  </features>
>  <cpu mode='custom' match='exact'>
>    <model fallback='allow'>cpu64-rhel6</model>
>    <topology sockets='2' cores='2' threads='2'/>
>  </cpu>
>  <clock offset='localtime'>
>    <timer name='rtc' tickpolicy='catchup'/>
>    <timer name='pit' tickpolicy='delay'/>
>    <timer name='hpet' present='no'/>
>    <timer name='hypervclock' present='yes'/>
>  </clock>
>  <on_poweroff>destroy</on_poweroff>
>  <on_reboot>restart</on_reboot>
>  <on_crash>restart</on_crash>
>  <pm>
>    <suspend-to-mem enabled='no'/>
>    <suspend-to-disk enabled='no'/>
>  </pm>
>  <devices>
>    ....
>    <interface type='bridge'>
>      <mac address='52:54:00:b1:41:b3'/>
>      <source bridge='br0'/>
>      <target dev='vnet4'/>
>      <model type='virtio'/>
>      <alias name='net0'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
>    </interface>
> .....
> 
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