Greetings,
I have a vm guest connected to a network bridge that is attached to a 10Gbe nic. When I do a bandwidth test between guest and host I am only getting 2Gbe. Any clues to what I could be missing?
I followed Configuring KVM on Clear Linux · ./brooks.sh guide for the most part.
Regards,
Interesting. Between host and guest on the same machine I would expect more throughput, and, this is definitely something we’d want to make sure users can get working.
I googled around a bit and found this:
https://www.linux-kvm.org/page/10G_NIC_performance:_VFIO_vs_virtio
It suggests that perhaps in the default configuration throughput is limited and you either want to switch to VFIO, or make sure the proper virtio commands are passed. I don’t know how this will look in libvirt speak, though - you’ll have to check that out yourself, or maybe others can chime in.
looks like the line: -device virtio-net-pci matters. I just don’t know how to add that to the vm defintion:
This is what I have for the vm:
<interface type='bridge'>
<mac address=''/>
<source bridge='lanbr'/>
<model type='virtio'/>
<address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</interface>
https://wiki.libvirt.org/page/Virtio#Network_driver
I can see that virtio_pci is not loaded:
lsmod | grep virtio
virtio_balloon 24576 0
virtio_net 49152 0
net_failover 20480 1 virtio_net
I checked the processes qemu process and it does have that flag set so back to square one. Would running a non linux guest os cause slowness?
How do you test the bandwidth? Found this:
I used iperf3 on guest and host
so I switched to linux based vm and numbers look way better. So I guess that’s my solution 