Re: VirtIO Net Tuning
Mike Tancsa <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.net |
|---|---|
| Message-ID | <[email protected]> |
On 3/25/2026 10:06 AM, Mark Saad wrote: > Hello All > I have been playing with FreeBSD 14.3-RELEASE and 15.0-REELASE amd64 > qemu powered vms on a Linux cloud hosting setup. I have noticed that > with VirtIO net ( vtnet ) interfaces there is some sort of tuning > required , or there is some sort of limitation on the packets per > second and overall throughput the nics can push. I am not able to get > any one interface to push more then 6Gb/s bursts and 5.5Gb/s > sustained. Before I go off the deep end with details has anyone run > into this , is this a known issue ? > Note, there were a bunch of important bug and performance fixes to vtnet interfaces between 14.3 and 14.4 so I would test with 14.4 for sure over 14.3. No tuning done below. vtnet0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1500 options=ec07bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6,HWSTATS> ether 52:54:00:0d:76:bc inet 192.168.122.15 netmask 0xffffff00 broadcast 192.168.122.255 media: Ethernet autoselect (10Gbase-T <full-duplex>) status: active nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> On a kvm hypervisor with an older xeon (E5-2690) to a RELENG_14 or RELENG_15 vm I get about 17Gbps in one direction. iperf3 -R -c 192.168.122.15 Connecting to host 192.168.122.15, port 5201 Reverse mode, remote host 192.168.122.15 is sending [ 5] local 192.168.122.1 port 48864 connected to 192.168.122.15 port 5201 [ ID] Interval Transfer Bitrate [ 5] 0.00-1.00 sec 1.90 GBytes 16.3 Gbits/sec [ 5] 1.00-2.00 sec 2.03 GBytes 17.4 Gbits/sec [ 5] 2.00-3.00 sec 2.04 GBytes 17.5 Gbits/sec [ 5] 3.00-4.00 sec 2.02 GBytes 17.3 Gbits/sec [ 5] 4.00-5.00 sec 2.00 GBytes 17.2 Gbits/sec [ 5] 5.00-6.00 sec 2.00 GBytes 17.2 Gbits/sec [ 5] 6.00-7.00 sec 2.01 GBytes 17.3 Gbits/sec [ 5] 7.00-8.00 sec 2.03 GBytes 17.4 Gbits/sec [ 5] 8.00-9.00 sec 2.03 GBytes 17.5 Gbits/sec [ 5] 9.00-10.00 sec 2.76 GBytes 23.7 Gbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 20.8 GBytes 17.9 Gbits/sec 0 sender [ 5] 0.00-10.00 sec 20.8 GBytes 17.9 Gbits/sec receiver ---Mike