vioif performance issues

[Chavdar Ivanov <ci4ic4%gmail.com@localhost>]

Hi,

I've noticed recently a certain slow-down in the network speed of one
of my NetBSD-current vms - a q35 guest of a proxmox server living on a
2.5 gb/s LAN. The host itself and any Linux guest get iperf3 speeds
close enough to wire speeds:
....
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   285 MBytes  2.39 Gbits/sec    0   4.16 MBytes
[  5]   1.00-2.00   sec   283 MBytes  2.38 Gbits/sec    0   4.16 MBytes
[  5]   2.00-3.00   sec   283 MBytes  2.37 Gbits/sec    0   4.16 MBytes

or thereabouts; the NetBSD guest gets:
...
[  5] local 192.168.0.49 port 52011 connected to 192.168.0.250 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   640 KBytes  5.24 Mbits/sec    0    451 KBytes
[  5]   1.00-2.00   sec   512 KBytes  4.19 Mbits/sec   18    225 KBytes
[  5]   2.00-3.00   sec   178 MBytes  1.49 Gbits/sec    6    107 KBytes
[  5]   3.00-4.00   sec   203 MBytes  1.71 Gbits/sec    0   27.1 KBytes
[  5]   4.00-5.01   sec   207 MBytes  1.73 Gbits/sec    0    164 KBytes
[  5]   5.01-6.00   sec   206 MBytes  1.74 Gbits/sec    0    141 KBytes
[  5]   6.00-7.01   sec   186 MBytes  1.56 Gbits/sec    0   74.1 KBytes
[  5]   7.01-8.00   sec   193 MBytes  1.62 Gbits/sec    0    165 KBytes
[  5]   8.00-9.00   sec   160 MBytes  1.34 Gbits/sec    0    148 KBytes
[  5]   9.00-10.00  sec   147 MBytes  1.23 Gbits/sec    0   1.43 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  1.45 GBytes  1.24 Gbits/sec   24             sender
[  5]   0.00-10.00  sec  1.45 GBytes  1.24 Gbits/sec                  receiver

(notice the first two readings...)

I am also getting a lot

...
[ 127692.297500] vioif0: can't handle af18
[ 127692.497517] vioif0: can't handle af18
[ 127692.698532] vioif0: can't handle af18
[ 127692.898515] vioif0: can't handle af18
...

dmesg spam.

This is on a pretty recent system:

# uname -a
# uname -a
NetBSD ym1r.lorien.lan 10.99.12 NetBSD 10.99.12 (GENERIC) #0: Sun Oct
13 03:06:39 BST 2024
root%ym1r.lorien.lan@localhost:/bd/sysbuild/amd64/obj/home/sysbuild/src/sys/arch/amd64/compile/GENERIC
amd64

Chavdar


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