Expose 1Gb nic using virtio device
- Thread starter jdl
- Start date
The link speed for a virtio adapter is just a "fake" and does not count. See http://serverfault.com/questions/738840/get-link-speed-of-an-virtio-net-network-adapter.
Thank you for the link.
The base issue was "if i use virtio drivers, ICMP works but TCP/UDP doesn't", so at first i thought it could be some MTU issue related to 10Gb vs 1Gb.
With virtio the VM behind pfSense can't connect anywhere.
If i switch to E1000 drivers, pfSense works correctly.
Any idea what coud cause this behavior with virtio drivers ?
The base issue was "if i use virtio drivers, ICMP works but TCP/UDP doesn't", so at first i thought it could be some MTU issue related to 10Gb vs 1Gb.
With virtio the VM behind pfSense can't connect anywhere.
If i switch to E1000 drivers, pfSense works correctly.
Any idea what coud cause this behavior with virtio drivers ?
I have the same problem with the recent FreeBSD 10.2 guests.
E1000 driver works well, but also does not deliver full speed.
Downloading file from host system: 60 MBps, from guest: 5-10 MBps depending on TSO on/off.
There is no problem with Ubuntu 14 guest, it gives full speed.
E1000 driver works well, but also does not deliver full speed.
Downloading file from host system: 60 MBps, from guest: 5-10 MBps depending on TSO on/off.
There is no problem with Ubuntu 14 guest, it gives full speed.
Difficult to say without having the configuration in detail.
Juts one hint: you cannot rely that only changing the virtual NIC´s type the other parameters - as seen in the VM - remain as they were; i.e. the assignment which one is eth0, eth1 etc. can be different!
If you cannot make a conclusion studying the configuration: track IP packets by investigating them with tcpdump.
I also checked the assignment when changing the drivers 
By default, pfSense ask you to reassign the interfaces when the driver changes.
Anyway, disabling "Hardware Checksum Offload" in System/Advanced/Networking fixed the issue.
Iperf with virtio gives 1.4Gb/s, all protocols are ok, and a real http download hits 100MB/s.
It's explained here : https://doc.pfsense.org/index.php/Lost_Traffic_/_Packets_Disappear and here https://forum.proxmox.com/threads/high-cpu-idle-usage-with-pfsense-openbsd.19695 .
For FreeBSD guests, i think the related tunable is 'hw.vtnet.X.csum_disable' : https://www.freebsd.org/cgi/man.cgi?query=vtnet&sektion=4 .
Thanks for your help.
By default, pfSense ask you to reassign the interfaces when the driver changes.
Anyway, disabling "Hardware Checksum Offload" in System/Advanced/Networking fixed the issue.
Iperf with virtio gives 1.4Gb/s, all protocols are ok, and a real http download hits 100MB/s.
It's explained here : https://doc.pfsense.org/index.php/Lost_Traffic_/_Packets_Disappear and here https://forum.proxmox.com/threads/high-cpu-idle-usage-with-pfsense-openbsd.19695 .
For FreeBSD guests, i think the related tunable is 'hw.vtnet.X.csum_disable' : https://www.freebsd.org/cgi/man.cgi?query=vtnet&sektion=4 .
Thanks for your help.
