iperf client in docker and without docker shows different statistics

[SergiiShapoval]

Hi,
I have found a huge difference between an output of iperf client and iperf client wrapped in docker:

Output from iperf client
`
[centos@host ~]$ iperf3 -A 0 -u -c 10.10.0.35 -p 44500 -b 0 --get-server-output
Connecting to host 10.10.0.35, port 44500
[ 4] local 10.10.252.57 port 51291 connected to 10.10.0.35 port 44500
[ ID] Interval Transfer Bandwidth Total Datagrams
[ 4] 0.00-1.00 sec 462 MBytes 3.88 Gbits/sec 334810
[ 4] 1.00-2.00 sec 465 MBytes 3.90 Gbits/sec 336830
[ 4] 2.00-3.00 sec 467 MBytes 3.92 Gbits/sec 338180
[ 4] 3.00-4.00 sec 464 MBytes 3.90 Gbits/sec 336250
[ 4] 4.00-5.00 sec 461 MBytes 3.87 Gbits/sec 334170
[ 4] 5.00-6.00 sec 473 MBytes 3.97 Gbits/sec 342780
[ 4] 6.00-7.00 sec 469 MBytes 3.93 Gbits/sec 339580
[ 4] 7.00-8.00 sec 470 MBytes 3.94 Gbits/sec 340370
[ 4] 8.00-9.00 sec 475 MBytes 3.98 Gbits/sec 343810
[ 4] 9.00-10.00 sec 477 MBytes 4.00 Gbits/sec 345150

---

[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 4] 0.00-10.00 sec 4.57 GBytes 3.93 Gbits/sec 0.015 ms 2518789/3390887 (74%)
[ 4] Sent 3390887 datagrams

Server output:

Accepted connection from 10.10.252.57, port 37124
[ 5] local 172.17.0.2 port 5201 connected to 10.10.252.57 port 51291
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 5] 0.00-1.00 sec 162 MBytes 1.36 Gbits/sec 0.019 ms 203325/320725 (63%)
[ 5] 1.00-2.00 sec 114 MBytes 956 Mbits/sec 0.019 ms 254055/336558 (75%)
[ 5] 2.00-3.00 sec 116 MBytes 971 Mbits/sec 0.022 ms 254417/338231 (75%)
[ 5] 3.00-4.00 sec 116 MBytes 971 Mbits/sec 0.019 ms 252429/336232 (75%)
[ 5] 4.00-5.00 sec 116 MBytes 969 Mbits/sec 0.020 ms 250155/333833 (75%)
[ 5] 5.00-6.00 sec 116 MBytes 971 Mbits/sec 0.018 ms 259051/342872 (76%)
[ 5] 6.00-7.00 sec 115 MBytes 967 Mbits/sec 0.020 ms 256176/339650 (75%)
[ 5] 7.00-8.00 sec 114 MBytes 959 Mbits/sec 0.022 ms 257370/340171 (76%)
[ 5] 8.00-9.00 sec 116 MBytes 969 Mbits/sec 0.012 ms 260174/343846 (76%)
[ 5] 9.00-10.00 sec 116 MBytes 971 Mbits/sec 0.018 ms 261258/345077 (76%)

iperf Done.
`

Output from iperf client wrapped in docker:
`[centos@host ~]$ sudo docker run -it --rm networkstatic/iperf3 -A 0 -u -c 10.10.0.35 -p 44500 -b 0 --get-server-output
Connecting to host 10.10.0.35, port 44500
[ 4] local 172.17.0.5 port 34345 connected to 10.10.0.35 port 44500
[ ID] Interval Transfer Bandwidth Total Datagrams
[ 4] 0.00-1.00 sec 718 MBytes 6.02 Gbits/sec 91940
[ 4] 1.00-2.00 sec 724 MBytes 6.07 Gbits/sec 92650
[ 4] 2.00-3.00 sec 722 MBytes 6.06 Gbits/sec 92470
[ 4] 3.00-4.00 sec 723 MBytes 6.07 Gbits/sec 92570
[ 4] 4.00-5.00 sec 713 MBytes 5.98 Gbits/sec 91290
[ 4] 5.00-6.00 sec 715 MBytes 6.00 Gbits/sec 91570
[ 4] 6.00-7.00 sec 713 MBytes 5.98 Gbits/sec 91290
[ 4] 7.00-8.00 sec 719 MBytes 6.03 Gbits/sec 92000
[ 4] 8.00-9.00 sec 719 MBytes 6.03 Gbits/sec 92080
[ 4] 9.00-10.00 sec 728 MBytes 6.10 Gbits/sec 93150

---

[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 4] 0.00-10.00 sec 7.03 GBytes 6.04 Gbits/sec 0.149 ms 804838/806269 (1e+02%)
[ 4] Sent 806269 datagrams

Server output:

Accepted connection from 10.10.252.57, port 52422
[ 5] local 172.17.0.2 port 5201 connected to 10.10.252.57 port 34345
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 5] 0.00-1.00 sec 11.1 MBytes 93.2 Mbits/sec 0.065 ms 62345/63768 (98%)
[ 5] 1.00-2.00 sec 8.00 KBytes 65.5 Kbits/sec 0.103 ms 28172/28173 (1e+02%)
[ 5] 2.00-3.00 sec 0.00 Bytes 0.00 bits/sec 0.103 ms 0/0 (-nan%)
[ 5] 3.00-4.00 sec 8.00 KBytes 65.6 Kbits/sec 0.099 ms 221510/221511 (1e+02%)
[ 5] 4.00-5.00 sec 0.00 Bytes 0.00 bits/sec 0.099 ms 0/0 (-nan%)
[ 5] 5.00-6.00 sec 0.00 Bytes 0.00 bits/sec 0.099 ms 0/0 (-nan%)
[ 5] 6.00-7.00 sec 0.00 Bytes 0.00 bits/sec 0.099 ms 0/0 (-nan%)
[ 5] 7.00-8.00 sec 0.00 Bytes 0.00 bits/sec 0.099 ms 0/0 (-nan%)
[ 5] 8.00-9.00 sec 48.0 KBytes 394 Kbits/sec 0.149 ms 492811/492817 (1e+02%)
[ 5] 9.00-10.00 sec 0.00 Bytes 0.00 bits/sec 0.149 ms 0/0 (-nan%)

iperf Done.
`

Do we need to launch docker in a special mode to receive more accurate output?

[SergiiShapoval]

no such issue exist in https://hub.docker.com/r/mlabbe/iperf3/