Hi Amru, Iperf is notoriously poor at measuring UDP performance, as packets get lost in the tool itself. Look at CPU usage and you may see what's going on
Try nuttcp instead - I dont think this is an OVS issue Regards, Jeroen Sent from my iPhone > On Jul 2, 2016, at 09:54, Amru OM <[email protected]> wrote: > > Greetings, > > > > I have installed the latest OVS 2.5 in each physical server of my testbed. > The physical servers running CentOS Linux release 7.2.1511 as the host > operating system. Also, each host has one VM running via KVM. The VM in each > server is connected to OVS through vNIC (e.g., tap0). Here is the command > line that I used to configure and start-up the VMs > > > > qemu-kvm -m 2048 -netdev > tap,id=hostnet0,script=/etc/ovs-ifup,downscript=/etc/ovs-ifdown,vhost=on > -device virtio-net-pci, > netdev=hostnet0,id=net0,mac=52:54:00:af:87:57,bus=pci.0,addr=0x3 -drive > file=/var/lib/libvirt/images/fedora.img -cpu host -smp cores=1,threads=2 > > > > the OVS (in each server) and the host NIC are configured as follows: > > > > ovs-vsctl add-br br0 > > ovs-vsctl add-port br0 eth0 > > ifconfig eth0 0 up > > ifconfig br0 10.0.0.x netmask 255.0.0.0 up > > > > eth0 above-mentioned is the physical NIC in the host and its link-speed is 56 > Gbits/sec. > > After configuring and running OVS and VM in each host, I tested the > bandwidth between two VMs located in different hosts via Iperf. When I test > the UDP bandwidth, where packets have large payload ( >= 10KB), the test > results show high packet loss rate. For example, when I run Iperf as follows: > > > > Iperf -u -c 10.0.0.x -l 10K -b 56G > > > > The test result of UDP bandwidth is 2.88 Gbits/sec, and packet loss rate ~ > 72%. This poor performance only occurs with UDP, but not with TCP. I just > wonder if I’m missing something here. > > > > > > Please advise and thank you in advance. > > _______________________________________________ > discuss mailing list > [email protected] > http://openvswitch.org/mailman/listinfo/discuss
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