iperf3 and Chelsio T6225-CR

I ran four tests yesterday using iperf3. The T6225-CR NIC still runs with Chelsio’s SM10G-SR optics. It’s amazing that receiving TCP streams runs at full speed. Sending TCP streams limps away only at a few megabits per second. This wasn’t expected at all. Even IPv6 runs faster than IPv4 for these particular tests. The Cisco switch at the other end uses Fiberworks’ SFP-10G-SR optics. Does anyone have any clues?

$ iperf3 -6Nc ping6.online.net -p 5202
Connecting to host ping6.online.net, port 5202
[  5] local 2001:700:1100:1::8 port 24418 connected to 2001:bc8:1::40 port 5202
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  26.7 MBytes   224 Mbits/sec    0   4.23 MBytes
[  5]   1.00-2.00   sec  37.6 MBytes   315 Mbits/sec  710    156 KBytes
[  5]   2.00-3.00   sec  2.84 MBytes  23.8 Mbits/sec  796   2.81 KBytes
[  5]   3.00-4.00   sec   435 KBytes  3.57 Mbits/sec   85   2.81 KBytes
[  5]   4.00-5.00   sec   273 KBytes  2.24 Mbits/sec   89   2.81 KBytes
[  5]   5.00-6.00   sec   439 KBytes  3.60 Mbits/sec   95   2.81 KBytes
[  5]   6.00-7.00   sec   385 KBytes  3.16 Mbits/sec   93   2.81 KBytes
[  5]   7.00-8.00   sec   361 KBytes  2.96 Mbits/sec   81   2.81 KBytes
[  5]   8.00-9.00   sec   375 KBytes  3.07 Mbits/sec   85   2.81 KBytes
[  5]   9.00-10.00  sec   402 KBytes  3.29 Mbits/sec  106   4.22 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  69.7 MBytes  58.5 Mbits/sec  2140             sender
[  5]   0.00-10.00  sec  55.5 MBytes  46.6 Mbits/sec                  receiver

iperf Done.
$ iperf3 -6NRc ping6.online.net -p 5202
Connecting to host ping6.online.net, port 5202
Reverse mode, remote host ping6.online.net is sending
[  5] local 2001:700:1100:1::8 port 26471 connected to 2001:bc8:1::40 port 5202
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  19.6 MBytes   165 Mbits/sec
[  5]   1.00-2.00   sec  92.8 MBytes   779 Mbits/sec
[  5]   2.00-3.00   sec   111 MBytes   927 Mbits/sec
[  5]   3.00-4.00   sec   111 MBytes   928 Mbits/sec
[  5]   4.00-5.00   sec   111 MBytes   928 Mbits/sec
[  5]   5.00-6.00   sec   111 MBytes   928 Mbits/sec
[  5]   6.00-7.00   sec   111 MBytes   928 Mbits/sec
[  5]   7.00-8.00   sec   111 MBytes   928 Mbits/sec
[  5]   8.00-9.00   sec   111 MBytes   928 Mbits/sec
[  5]   9.00-10.00  sec   110 MBytes   924 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  1008 MBytes   845 Mbits/sec    0             sender
[  5]   0.00-10.00  sec   997 MBytes   836 Mbits/sec                  receiver

iperf Done.
$ iperf3 -Nc ping.online.net -p 5202
Connecting to host ping.online.net, port 5202
[  5] local 128.39.174.8 port 14610 connected to 62.210.18.40 port 5202
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  6.92 MBytes  58.0 Mbits/sec    0   1.09 MBytes
[  5]   1.00-2.00   sec  64.5 MBytes   541 Mbits/sec   98   40.8 KBytes
[  5]   2.00-3.00   sec  4.35 MBytes  36.5 Mbits/sec  827   2.85 KBytes
[  5]   3.00-4.00   sec   420 KBytes  3.44 Mbits/sec  141   2.85 KBytes
[  5]   4.00-5.00   sec   397 KBytes  3.26 Mbits/sec   90   2.85 KBytes
[  5]   5.00-6.00   sec   475 KBytes  3.89 Mbits/sec  119   2.85 KBytes
[  5]   6.00-7.00   sec   287 KBytes  2.35 Mbits/sec  113   2.85 KBytes
[  5]   7.00-8.00   sec   376 KBytes  3.08 Mbits/sec  119   4.28 KBytes
[  5]   8.00-9.01   sec   382 KBytes  3.09 Mbits/sec  129   2.85 KBytes
[  5]   9.01-10.00  sec   486 KBytes  4.04 Mbits/sec  111   2.85 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  78.5 MBytes  65.8 Mbits/sec  1747             sender
[  5]   0.00-10.00  sec  64.3 MBytes  53.9 Mbits/sec                  receiver

iperf Done.
$ iperf3 -NRc ping.online.net -p 5202
Connecting to host ping.online.net, port 5202
Reverse mode, remote host ping.online.net is sending
[  5] local 128.39.174.8 port 13284 connected to 62.210.18.40 port 5202
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  14.7 MBytes   123 Mbits/sec
[  5]   1.00-2.00   sec  55.5 MBytes   466 Mbits/sec
[  5]   2.00-3.00   sec  64.5 MBytes   541 Mbits/sec
[  5]   3.00-4.00   sec  69.8 MBytes   585 Mbits/sec
[  5]   4.00-5.00   sec  72.6 MBytes   609 Mbits/sec
[  5]   5.00-6.00   sec  76.1 MBytes   638 Mbits/sec
[  5]   6.00-7.00   sec  77.8 MBytes   653 Mbits/sec
[  5]   7.00-8.00   sec  79.8 MBytes   670 Mbits/sec
[  5]   8.00-9.00   sec  80.5 MBytes   675 Mbits/sec
[  5]   9.00-10.00  sec  81.7 MBytes   685 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec   681 MBytes   571 Mbits/sec  2079             sender
[  5]   0.00-10.00  sec   673 MBytes   565 Mbits/sec                  receiver

iperf Done.

Published by

Trond Endrestøl

I stopped counting my age years ago. Personal interests besides computers and computer networks include, but are not limited to, astronomy, comics, music, and science (fiction).

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