poor performance when running iperf3 on Intel I219-LM #277
Description
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Describe the bug
Machine has two Intel NIC I219-LM(0x15fb) and I210(0x1533). I tested two NIC using iperf3. I210 worked fine, 900+Mbps with --bidir. But I219-LM only have 300+Mbps on TX with --bidir and -w is not working. Bitrate is normal when testing one direction without --bidir or with -R.
Tests on latest FreeBSD 14.3 are interesting. First round is basically the same as OPNsense. But later round bitrate comes to 800+Mbps. Having a rest for minutes and start a new round bitrate drops to 500Mbps.
I also tested on archiso. Result on archiso is normal.
https://docs.netgate.com/pfsense/en/latest/hardware/tune.html
https://docs.opnsense.org/troubleshooting/performance.html
Tips from above almost no effects on test. There is no drop. But net.inet.tcp.tso default value is 1, TSO4 and TOS6 are not showed in ifconfig.
Machine was run as iperf3 client. Both NICs are configured as LAN in the test and acquire IP via DHCP. Offloading settings are kept default. iperf3 server is archlinux i7-10700 Realtek 8168. Machine and iperf3 server are connected by a switch.
To Reproduce
Steps to reproduce the behavior:
- Fresh install on a machine with Intel I219-LM(0x15fb)
- Running
iperf3 -c 192.168.1.160 --bidir
Expected behavior
Bitrate in both direction goes to 900+Mbps.
Describe alternatives you considered
Screenshots
Relevant log files
Test output on OPNsense
root@OPNsense:~ # iperf3 -c 192.168.1.160 --bidir
Connecting to host 192.168.1.160, port 5201
[ 5] local 192.168.1.120 port 4608 connected to 192.168.1.160 port 5201
[ 7] local 192.168.1.120 port 65221 connected to 192.168.1.160 port 5201
[ ID][Role] Interval Transfer Bitrate Retr Cwnd
[ 5][TX-C] 0.00-1.00 sec 37.2 MBytes 312 Mbits/sec 38 70.0 KBytes
[ 7][RX-C] 0.00-1.00 sec 112 MBytes 938 Mbits/sec
[ 5][TX-C] 1.00-2.02 sec 35.8 MBytes 293 Mbits/sec 25 84.1 KBytes
[ 7][RX-C] 1.00-2.02 sec 115 MBytes 940 Mbits/sec
[ 5][TX-C] 2.02-3.00 sec 35.2 MBytes 303 Mbits/sec 22 103 KBytes
[ 7][RX-C] 2.02-3.00 sec 109 MBytes 939 Mbits/sec
[ 5][TX-C] 3.00-4.00 sec 39.2 MBytes 329 Mbits/sec 26 103 KBytes
[ 7][RX-C] 3.00-4.00 sec 112 MBytes 940 Mbits/sec
[ 5][TX-C] 4.00-5.00 sec 35.2 MBytes 296 Mbits/sec 37 56.6 KBytes
[ 7][RX-C] 4.00-5.00 sec 112 MBytes 940 Mbits/sec
[ 5][TX-C] 5.00-6.00 sec 39.5 MBytes 331 Mbits/sec 26 63.2 KBytes
[ 7][RX-C] 5.00-6.00 sec 112 MBytes 938 Mbits/sec
[ 5][TX-C] 6.00-7.04 sec 38.4 MBytes 310 Mbits/sec 28 49.6 KBytes
[ 7][RX-C] 6.00-7.04 sec 116 MBytes 940 Mbits/sec
[ 5][TX-C] 7.04-8.00 sec 31.8 MBytes 277 Mbits/sec 26 77.9 KBytes
[ 7][RX-C] 7.04-8.00 sec 108 MBytes 939 Mbits/sec
[ 5][TX-C] 8.00-9.00 sec 39.6 MBytes 332 Mbits/sec 34 67.7 KBytes
[ 7][RX-C] 8.00-9.00 sec 112 MBytes 939 Mbits/sec
[ 5][TX-C] 9.00-10.00 sec 31.5 MBytes 264 Mbits/sec 29 58.9 KBytes
[ 7][RX-C] 9.00-10.00 sec 112 MBytes 939 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval Transfer Bitrate Retr
[ 5][TX-C] 0.00-10.00 sec 364 MBytes 305 Mbits/sec 291 sender
[ 5][TX-C] 0.00-10.00 sec 363 MBytes 304 Mbits/sec receiver
[ 7][RX-C] 0.00-10.00 sec 1.10 GBytes 941 Mbits/sec 0 sender
[ 7][RX-C] 0.00-10.00 sec 1.09 GBytes 939 Mbits/sec receiver
iperf Done.
root@OPNsense:~ # iperf3 -c 192.168.1.160 --bidir
Connecting to host 192.168.1.160, port 5201
[ 5] local 192.168.1.120 port 5782 connected to 192.168.1.160 port 5201
[ 7] local 192.168.1.120 port 48171 connected to 192.168.1.160 port 5201
[ ID][Role] Interval Transfer Bitrate Retr Cwnd
[ 5][TX-C] 0.00-1.00 sec 34.4 MBytes 288 Mbits/sec 28 68.3 KBytes
[ 7][RX-C] 0.00-1.00 sec 112 MBytes 939 Mbits/sec
[ 5][TX-C] 1.00-2.00 sec 33.0 MBytes 277 Mbits/sec 35 71.0 KBytes
[ 7][RX-C] 1.00-2.00 sec 112 MBytes 938 Mbits/sec
[ 5][TX-C] 2.00-3.00 sec 34.4 MBytes 288 Mbits/sec 32 72.0 KBytes
[ 7][RX-C] 2.00-3.00 sec 112 MBytes 940 Mbits/sec
[ 5][TX-C] 3.00-4.06 sec 38.4 MBytes 303 Mbits/sec 29 91.6 KBytes
[ 7][RX-C] 3.00-4.06 sec 119 MBytes 939 Mbits/sec
[ 5][TX-C] 4.06-5.02 sec 34.6 MBytes 302 Mbits/sec 27 74.7 KBytes
[ 7][RX-C] 4.06-5.02 sec 108 MBytes 939 Mbits/sec
[ 5][TX-C] 5.02-6.00 sec 35.8 MBytes 307 Mbits/sec 29 63.7 KBytes
[ 7][RX-C] 5.02-6.00 sec 109 MBytes 938 Mbits/sec
[ 5][TX-C] 6.00-7.00 sec 36.6 MBytes 307 Mbits/sec 25 82.3 KBytes
[ 7][RX-C] 6.00-7.00 sec 112 MBytes 940 Mbits/sec
[ 5][TX-C] 7.00-8.00 sec 35.0 MBytes 294 Mbits/sec 27 120 KBytes
[ 7][RX-C] 7.00-8.00 sec 112 MBytes 938 Mbits/sec
[ 5][TX-C] 8.00-9.00 sec 36.2 MBytes 304 Mbits/sec 29 95.9 KBytes
[ 7][RX-C] 8.00-9.00 sec 112 MBytes 940 Mbits/sec
[ 5][TX-C] 9.00-10.00 sec 35.0 MBytes 294 Mbits/sec 33 63.3 KBytes
[ 7][RX-C] 9.00-10.00 sec 112 MBytes 938 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval Transfer Bitrate Retr
[ 5][TX-C] 0.00-10.00 sec 353 MBytes 296 Mbits/sec 294 sender
[ 5][TX-C] 0.00-10.00 sec 353 MBytes 296 Mbits/sec receiver
[ 7][RX-C] 0.00-10.00 sec 1.10 GBytes 941 Mbits/sec 0 sender
[ 7][RX-C] 0.00-10.00 sec 1.09 GBytes 939 Mbits/sec receiver
iperf Done.
root@OPNsense:~ #
Test output on FreeBSD 14.3
dgkj@dgkj-Default-string:~ $ iperf3 -c 192.168.1.160 --bidir && iperf3 -c 192.168.1.160 --bidir
Connecting to host 192.168.1.160, port 5201
[ 5] local 192.168.1.120 port 54489 connected to 192.168.1.160 port 5201
[ 7] local 192.168.1.120 port 41004 connected to 192.168.1.160 port 5201
[ ID][Role] Interval Transfer Bitrate Retr Cwnd
[ 5][TX-C] 0.00-1.06 sec 116 MBytes 914 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 0.00-1.06 sec 48.0 MBytes 379 Mbits/sec
[ 5][TX-C] 1.06-2.03 sec 107 MBytes 933 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 1.06-2.03 sec 28.4 MBytes 247 Mbits/sec
[ 5][TX-C] 2.03-3.06 sec 115 MBytes 932 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 2.03-3.06 sec 30.5 MBytes 247 Mbits/sec
[ 5][TX-C] 3.06-4.01 sec 106 MBytes 932 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 3.06-4.01 sec 28.1 MBytes 248 Mbits/sec
[ 5][TX-C] 4.01-5.00 sec 110 MBytes 932 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 4.01-5.00 sec 29.1 MBytes 247 Mbits/sec
[ 5][TX-C] 5.00-6.00 sec 111 MBytes 932 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 5.00-6.00 sec 29.4 MBytes 246 Mbits/sec
[ 5][TX-C] 6.00-7.01 sec 112 MBytes 933 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 6.00-7.01 sec 29.8 MBytes 248 Mbits/sec
[ 5][TX-C] 7.01-8.02 sec 112 MBytes 933 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 7.01-8.02 sec 29.8 MBytes 248 Mbits/sec
[ 5][TX-C] 8.02-9.03 sec 113 MBytes 932 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 8.02-9.04 sec 30.1 MBytes 248 Mbits/sec
[ 5][TX-C] 9.03-10.06 sec 114 MBytes 931 Mbits/sec 0 4.31 MBytes
[ 7][RX-C] 9.04-10.06 sec 30.2 MBytes 248 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval Transfer Bitrate Retr
[ 5][TX-C] 0.00-10.06 sec 1.09 GBytes 931 Mbits/sec 0 sender
[ 5][TX-C] 0.00-10.08 sec 1.09 GBytes 929 Mbits/sec receiver
[ 7][RX-C] 0.00-10.06 sec 316 MBytes 264 Mbits/sec 0 sender
[ 7][RX-C] 0.00-10.08 sec 313 MBytes 261 Mbits/sec receiver
iperf Done.
Connecting to host 192.168.1.160, port 5201
[ 5] local 192.168.1.120 port 45543 connected to 192.168.1.160 port 5201
[ 7] local 192.168.1.120 port 10903 connected to 192.168.1.160 port 5201
[ ID][Role] Interval Transfer Bitrate Retr Cwnd
[ 5][TX-C] 0.00-1.00 sec 111 MBytes 932 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 0.00-1.00 sec 103 MBytes 867 Mbits/sec
[ 5][TX-C] 1.00-2.06 sec 118 MBytes 929 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 1.00-2.06 sec 106 MBytes 834 Mbits/sec
[ 5][TX-C] 2.06-3.00 sec 104 MBytes 928 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 2.06-3.00 sec 93.4 MBytes 835 Mbits/sec
[ 5][TX-C] 3.00-4.00 sec 111 MBytes 930 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 3.00-4.00 sec 99.5 MBytes 835 Mbits/sec
[ 5][TX-C] 4.00-5.00 sec 110 MBytes 927 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 4.00-5.00 sec 99.2 MBytes 833 Mbits/sec
[ 5][TX-C] 5.00-6.04 sec 115 MBytes 928 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 5.00-6.04 sec 104 MBytes 835 Mbits/sec
[ 5][TX-C] 6.04-7.00 sec 106 MBytes 930 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 6.04-7.00 sec 95.2 MBytes 835 Mbits/sec
[ 5][TX-C] 7.00-8.00 sec 111 MBytes 929 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 7.00-8.00 sec 99.6 MBytes 835 Mbits/sec
[ 5][TX-C] 8.00-9.00 sec 111 MBytes 928 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 8.00-9.00 sec 99.4 MBytes 834 Mbits/sec
[ 5][TX-C] 9.00-10.00 sec 111 MBytes 929 Mbits/sec 0 4.07 MBytes
[ 7][RX-C] 9.00-10.00 sec 99.6 MBytes 836 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval Transfer Bitrate Retr
[ 5][TX-C] 0.00-10.00 sec 1.08 GBytes 929 Mbits/sec 0 sender
[ 5][TX-C] 0.00-10.02 sec 1.08 GBytes 928 Mbits/sec receiver
[ 7][RX-C] 0.00-10.00 sec 1002 MBytes 841 Mbits/sec 0 sender
[ 7][RX-C] 0.00-10.02 sec 999 MBytes 836 Mbits/sec receiver
iperf Done.
dgkj@dgkj-Default-string:~ $
Additional context
Similar issue
https://forums.freebsd.org/threads/i219-lm-network-card-port-speed-problem.79679/
https://forum.netgate.com/topic/162625/i219-lm-network-card-port-speed-problem
Environment
Software version used and hardware type if relevant, e.g.:
Test machine
iperf 3.20 (cJSON 1.7.15)
FreeBSD OPNsense.internal 14.3-RELEASE-p7 FreeBSD 14.3-RELEASE-p7 stable/25.7-n271786-8d37907deeb8 SMP amd64
11th Gen Intel(R) Core(TM) i5-1145G7E @ 2.60GHz
Intel(R) Core(TM) i5-1145G7E
em0@pci0:0:31:6: class=0x020000 rev=0x20 hdr=0x00 vendor=0x8086 device=0x15fb subvendor=0x8086 subdevice=0x0000
vendor = 'Intel Corporation'
device = 'Ethernet Connection (13) I219-LM'
class = network
subclass = ethernet
igb0@pci0:3:0:0: class=0x020000 rev=0x03 hdr=0x00 vendor=0x8086 device=0x1533 subvendor=0xffff subdevice=0x0000
vendor = 'Intel Corporation'
device = 'I210 Gigabit Network Connection'
class = network
subclass = ethernet
iperf3 server
iperf 3.20 (cJSON 1.7.15)
Linux archlinux 6.18.5-arch1-1 #1 SMP PREEMPT_DYNAMIC Sun, 11 Jan 2026 17:10:53 +0000 x86_64 GNU/Linux
Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz
Realtek Semiconductor Co., Ltd. RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet Controller (rev 15)