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Subject: Re: [virtio-dev] [PATCH v4] content: Introduce VIRTIO_NET_F_STANDBY feature
On Wed, Nov 21, 2018 at 10:04:53PM +0200, Sameeh Jubran wrote: > On Wed, Nov 21, 2018 at 8:41 PM Michael S. Tsirkin <email@example.com> wrote: > > > > Great to see you making progress on this! > > Some comments below: > > > > On Wed, Nov 21, 2018 at 05:39:38PM +0200, Sameeh Jubran wrote: > > > I have created a setup which has two hosts (host A and host B) with X710 10G > > > cards connected back to back. On one host (I'll refer to this host as host A) I > > > have configured a bridge with the PF interface as well as vitio-net's interface > > > (standby) both attached to it. > > > > ... > > > > > The command line I used: > > > > > > /root/qemu/x86_64-softmmu/qemu-system-x86_64 \ > > > -netdev tap,id=hostnet0,script=world_bridge_standalone.sh,downscript=no,ifname= > > > cc17 \ > > > -device e1000,netdev=hostnet0,mac=56:cc:c1:01:cc:21,id=cc17 \ > > > > What's e1000 doing here? > > Can this be reason you can not talk to host? > I don't think so, the e1000 is for enabling WAN connection on the > guest for downloading packages and ssh connection. It is connected to > a separate bridge which is connected to the external interface of the > host. > > > > > -netdev tap,vhost=on,id=hostnet1,script=test_bridge_standalone.sh,downscript= > > > no,ifname=cc1_72,queues=4 \ > > > -device virtio-net,host_mtu=1500,netdev=hostnet1,mac=8a:f7:20:29:3b:cb,id= > > > cc1_72,vectors=10,mq=on,primary=cc1_71 \ > > > -device vfio-pci,host=65:02.1,id=cc1_71,standby=cc1_72 \ > > > -enable-kvm \ > > > -name netkvm \ > > > -m 3000M \ > > > -drive file=/dev/shm/fedora_29.qcow2,if=ide,id=drivex \ > > > -smp 4 \ > > > -vga qxl \ > > > -spice port=6110,disable-ticketing \ > > > -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x7 \ > > > -chardev spicevmc,name=vdagent,id=vdagent \ > > > -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,name= > > > com.redhat.spice.0 \ > > > -chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 \ > > > -device virtio-serial \ > > > -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0 \ > > > -monitor stdio > > > > > > ... > > > > > Since I couldn't ping from VM to host B, I did an iperf test between the VM and > > > host A with the feature enabled and during the test I have unplugged the sriov > > > device, the device was unplugged successfully and no drops where observed as > > > you can see in the results below: > > > > > > [root@dhcp156-44 ~]# ifconfig > > > > Well I suspect this won't tell you anything, this shows packet drops at > > the hardware level. When e.g. link is down linux won't send any packets > > out. The simplest test is to monitor latency and throughput and see that > > while it is lower for the duration of migration, there are no huge > > spikes around the switch. > Oh, okay will do that. > > I have noticed some nasty lag when I tried to ssh to the VM using the > failover interface while I didn't experience that with the e1000. > Sridhar Any idea what might be the cause? Try tcpdump? > > > > -- > > MST > > > > -- > Respectfully, > Sameeh Jubran > Linkedin > Software Engineer @ Daynix.