2012/12/3 Davide Guerri <d.guerri@unidata.it>
Hi, I'm having some weird problem with the setup of the QoS on a bridged network.
As the docs states, outbound/inbound average speed should be expressed in KBps (KBytes per second) but in order to get a maximum speed of 10Mbps (megabits per second) surprising enough I have to use 2560 on the guest (not 1280 as expected). Using 1280 units I get a speed og 5Mbps.
I'm aware of peak and burst parameters but even with them I'm seeing the same (long-term) behavior.
Here follows my configuration.
Thank you in advance for any help you can provide.
Domain definition (relevant part only)
virsh # dumpxml mydomain <domain type='kvm' id='45'> [...] <devices> [...] <interface type='network'> <mac address='52:54:00:xx:xx:xx'/> <source network='br909'/> <target dev='vnet43'/> <model type='virtio'/> <bandwidth> <inbound average='2560'/> <outbound average='2560'/> </bandwidth> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> [...] </devices> </domain>
The network definition: virsh # net-dumpxml br909 <network> <name>br909</name> <uuid>07319380-2025-cdcc-924a-149cd0370b56</uuid> <forward mode='bridge'/> <bridge name='br909' /> </network>
And iperf result (client and server are on the same vlan and they are running on the same host)
[ 5] local xx.xx.xx.xx port 5001 connected with xx.xx.xx.yy port 18396 [ 5] 0.0-30.1 sec 35.4 MBytes 9.87 Mbits/sec
provide your os version and libvirt version plz. and use the following command to check the tc mtu size: tc filter list dev vnet0 root if the mtu size in the output is not 64kb,then you must update your libvirt to 0.9.11 or later.