Can anyone with 10/40Gb experience explain these results?

I’m seeing EXTREMELY poor iperf3 results when doing testing between two linux servers that have Mellanox ConnectX-3 dual port NICs, each with one port connected to my CRS354. So poor that I know I might either have a hardware issue on one/both of my ports or something is wrong with my switch config that I just can’t find. I have also attached my entire CRS354 config. It’s pretty basic at this moment as I just got it and wanted to get all of this straightened out before I start doing more advanced/permanent config.

NOTE I have tested the below with three different sets/brands of QSFP+ DAC cables.

Below are iperf3 results (both single and 2 parallel connections) between two Linux boxes each of which are connected to the CRS354 with DAC QSFP+ cables. As you can see the results are absolutely abysmal.

[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  4.18 MBytes  35.1 Mbits/sec  153   9.90 KBytes       
[  5]   1.00-2.00   sec  4.59 MBytes  38.5 Mbits/sec  153   1.41 KBytes       
[  5]   2.00-3.00   sec  10.5 MBytes  87.9 Mbits/sec  322   2.83 KBytes       
[  5]   3.00-4.00   sec  4.23 MBytes  35.4 Mbits/sec  143   1.41 KBytes       
[  5]   4.00-5.00   sec  6.68 MBytes  56.0 Mbits/sec  227   1.41 KBytes       
[  5]   5.00-6.00   sec  5.22 MBytes  43.8 Mbits/sec  187   1.41 KBytes       
[  5]   6.00-7.00   sec   255 KBytes  2.09 Mbits/sec   14   2.83 KBytes       
[  5]   7.00-8.00   sec  5.29 MBytes  44.4 Mbits/sec  217   1.41 KBytes       
[  5]   8.00-9.00   sec  6.46 MBytes  54.2 Mbits/sec  203   1.41 KBytes       
[  5]   9.00-10.00  sec  4.36 MBytes  36.6 Mbits/sec  147   1.41 KBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  51.7 MBytes  43.4 Mbits/sec  1766             sender
[  5]   0.00-10.00  sec  51.5 MBytes  43.2 Mbits/sec                  receiver


[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  6.57 MBytes  55.1 Mbits/sec  229   2.83 KBytes       
[  7]   0.00-1.00   sec  10.0 MBytes  84.1 Mbits/sec  319   1.41 KBytes       
[SUM]   0.00-1.00   sec  16.6 MBytes   139 Mbits/sec  548             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   1.00-2.00   sec  4.10 MBytes  34.4 Mbits/sec  143   1.41 KBytes       
[  7]   1.00-2.00   sec  4.16 MBytes  34.9 Mbits/sec  134   9.90 KBytes       
[SUM]   1.00-2.00   sec  8.26 MBytes  69.3 Mbits/sec  277             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   2.00-3.00   sec  4.60 MBytes  38.6 Mbits/sec  140   2.83 KBytes       
[  7]   2.00-3.00   sec  2.92 MBytes  24.5 Mbits/sec  114   2.83 KBytes       
[SUM]   2.00-3.00   sec  7.52 MBytes  63.1 Mbits/sec  254             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   3.00-4.00   sec   764 KBytes  6.26 Mbits/sec   30   2.83 KBytes       
[  7]   3.00-4.00   sec  3.60 MBytes  30.2 Mbits/sec  120   5.66 KBytes       
[SUM]   3.00-4.00   sec  4.35 MBytes  36.5 Mbits/sec  150             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   4.00-5.00   sec  7.21 MBytes  60.5 Mbits/sec  256   17.0 KBytes       
[  7]   4.00-5.00   sec  7.77 MBytes  65.2 Mbits/sec  241   18.4 KBytes       
[SUM]   4.00-5.00   sec  15.0 MBytes   126 Mbits/sec  497             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   5.00-6.00   sec  11.4 MBytes  95.9 Mbits/sec  381   5.66 KBytes       
[  7]   5.00-6.00   sec  2.42 MBytes  20.3 Mbits/sec   79   1.41 KBytes       
[SUM]   5.00-6.00   sec  13.9 MBytes   116 Mbits/sec  460             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   6.00-7.00   sec  2.36 MBytes  19.8 Mbits/sec   95   1.41 KBytes       
[  7]   6.00-7.00   sec  3.48 MBytes  29.2 Mbits/sec  103   7.07 KBytes       
[SUM]   6.00-7.00   sec  5.84 MBytes  49.0 Mbits/sec  198             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   7.00-8.00   sec  2.11 MBytes  17.7 Mbits/sec   60   1.41 KBytes       
[  7]   7.00-8.00   sec  1.30 MBytes  10.9 Mbits/sec   42   9.90 KBytes       
[SUM]   7.00-8.00   sec  3.42 MBytes  28.7 Mbits/sec  102             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   8.00-9.00   sec  5.72 MBytes  48.0 Mbits/sec  193   2.83 KBytes       
[  7]   8.00-9.00   sec   255 KBytes  2.09 Mbits/sec    6   5.66 KBytes       
[SUM]   8.00-9.00   sec  5.97 MBytes  50.1 Mbits/sec  199             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   9.00-10.00  sec  6.03 MBytes  50.6 Mbits/sec  218   2.83 KBytes       
[  7]   9.00-10.00  sec  3.91 MBytes  32.8 Mbits/sec  132   1.41 KBytes       
[SUM]   9.00-10.00  sec  9.94 MBytes  83.4 Mbits/sec  350             
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  50.9 MBytes  42.7 Mbits/sec  1745             sender
[  5]   0.00-10.00  sec  50.6 MBytes  42.4 Mbits/sec                  receiver
[  7]   0.00-10.00  sec  39.8 MBytes  33.4 Mbits/sec  1290             sender
[  7]   0.00-10.00  sec  39.6 MBytes  33.2 Mbits/sec                  receiver
[SUM]   0.00-10.00  sec  90.7 MBytes  76.1 Mbits/sec  3035             sender
[SUM]   0.00-10.00  sec  90.2 MBytes  75.6 Mbits/sec                  receiver

Now below, you will see two different iperf3 results. The first is a direct connection between NIC1 on Server1 and NIC1 on Server 2. The second is a direction connection between NIC2 on Server1 and NIC2 on Server2. I thought it important to test direct connections with both cables that I’m connecting to the CRS354 to eliminate them as the issue.

[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  3.74 GBytes  32.1 Gbits/sec    0   1.46 MBytes       
[  5]   1.00-2.00   sec  3.72 GBytes  32.0 Gbits/sec    0   1.55 MBytes       
[  5]   2.00-3.00   sec  3.73 GBytes  32.1 Gbits/sec    0   1.55 MBytes       
[  5]   3.00-4.00   sec  3.73 GBytes  32.0 Gbits/sec  190   1.30 MBytes       
[  5]   4.00-5.00   sec  3.72 GBytes  32.0 Gbits/sec    0   1.38 MBytes       
[  5]   5.00-6.00   sec  3.73 GBytes  32.0 Gbits/sec    0   1.38 MBytes       
[  5]   6.00-7.00   sec  3.72 GBytes  32.0 Gbits/sec    0   1.55 MBytes       
[  5]   7.00-8.00   sec  3.73 GBytes  32.1 Gbits/sec    0   1.55 MBytes       
[  5]   8.00-9.00   sec  3.49 GBytes  30.0 Gbits/sec    0   1.75 MBytes       
[  5]   9.00-10.00  sec  3.10 GBytes  26.6 Gbits/sec    0   1.75 MBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  36.4 GBytes  31.3 Gbits/sec  190             sender
[  5]   0.00-10.00  sec  36.4 GBytes  31.3 Gbits/sec                  receiver



[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  2.25 GBytes  19.3 Gbits/sec    0   1.31 MBytes       
[  7]   0.00-1.00   sec  2.12 GBytes  18.2 Gbits/sec    0   1.36 MBytes       
[SUM]   0.00-1.00   sec  4.37 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   1.00-2.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.31 MBytes       
[  7]   1.00-2.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.36 MBytes       
[SUM]   1.00-2.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   2.00-3.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.38 MBytes       
[  7]   2.00-3.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   2.00-3.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   3.00-4.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.45 MBytes       
[  7]   3.00-4.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   3.00-4.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   4.00-5.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.45 MBytes       
[  7]   4.00-5.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   4.00-5.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   5.00-6.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.45 MBytes       
[  7]   5.00-6.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   5.00-6.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   6.00-7.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.45 MBytes       
[  7]   6.00-7.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   6.00-7.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   7.00-8.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.45 MBytes       
[  7]   7.00-8.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   7.00-8.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   8.00-9.00   sec  2.18 GBytes  18.8 Gbits/sec    0   1.45 MBytes       
[  7]   8.00-9.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   8.00-9.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   9.00-10.00  sec  2.18 GBytes  18.7 Gbits/sec    0   1.45 MBytes       
[  7]   9.00-10.00  sec  2.18 GBytes  18.7 Gbits/sec    0   1.54 MBytes       
[SUM]   9.00-10.00  sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  21.9 GBytes  18.8 Gbits/sec    0             sender
[  5]   0.00-10.00  sec  21.9 GBytes  18.8 Gbits/sec                  receiver
[  7]   0.00-10.00  sec  21.8 GBytes  18.7 Gbits/sec    0             sender
[  7]   0.00-10.00  sec  21.7 GBytes  18.7 Gbits/sec                  receiver
[SUM]   0.00-10.00  sec  43.6 GBytes  37.5 Gbits/sec    0             sender
[SUM]   0.00-10.00  sec  43.6 GBytes  37.5 Gbits/sec                  receiver


[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  3.78 GBytes  32.5 Gbits/sec    0   1.56 MBytes       
[  5]   1.00-2.00   sec  3.77 GBytes  32.4 Gbits/sec    0   1.56 MBytes       
[  5]   2.00-3.00   sec  3.63 GBytes  31.2 Gbits/sec    0   1.56 MBytes       
[  5]   3.00-4.00   sec  3.40 GBytes  29.2 Gbits/sec    0   1.56 MBytes       
[  5]   4.00-5.00   sec  3.37 GBytes  28.9 Gbits/sec    0   1.56 MBytes       
[  5]   5.00-6.00   sec  3.41 GBytes  29.3 Gbits/sec    0   1.56 MBytes       
[  5]   6.00-7.00   sec  3.44 GBytes  29.6 Gbits/sec    0   1.56 MBytes       
[  5]   7.00-8.00   sec  3.43 GBytes  29.5 Gbits/sec    0   1.56 MBytes       
[  5]   8.00-9.00   sec  3.43 GBytes  29.4 Gbits/sec    0   1.56 MBytes       
[  5]   9.00-10.00  sec  3.41 GBytes  29.3 Gbits/sec    0   1.56 MBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  35.1 GBytes  30.1 Gbits/sec    0             sender
[  5]   0.00-10.00  sec  35.1 GBytes  30.1 Gbits/sec                  receiver


[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  2.17 GBytes  18.6 Gbits/sec    0   1.33 MBytes       
[  7]   0.00-1.00   sec  2.17 GBytes  18.6 Gbits/sec    0   1.38 MBytes       
[SUM]   0.00-1.00   sec  4.34 GBytes  37.3 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   1.00-2.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.33 MBytes       
[  7]   1.00-2.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.38 MBytes       
[SUM]   1.00-2.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   2.00-3.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.33 MBytes       
[  7]   2.00-3.00   sec  2.18 GBytes  18.8 Gbits/sec    0   1.38 MBytes       
[SUM]   2.00-3.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   3.00-4.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.33 MBytes       
[  7]   3.00-4.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.38 MBytes       
[SUM]   3.00-4.00   sec  4.37 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   4.00-5.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.33 MBytes       
[  7]   4.00-5.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.38 MBytes       
[SUM]   4.00-5.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   5.00-6.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.33 MBytes       
[  7]   5.00-6.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.38 MBytes       
[SUM]   5.00-6.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   6.00-7.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.48 MBytes       
[  7]   6.00-7.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   6.00-7.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   7.00-8.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.48 MBytes       
[  7]   7.00-8.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   7.00-8.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   8.00-9.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.48 MBytes       
[  7]   8.00-9.00   sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   8.00-9.00   sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   9.00-10.00  sec  2.18 GBytes  18.7 Gbits/sec    0   1.48 MBytes       
[  7]   9.00-10.00  sec  2.18 GBytes  18.7 Gbits/sec    0   1.46 MBytes       
[SUM]   9.00-10.00  sec  4.36 GBytes  37.5 Gbits/sec    0             
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  21.8 GBytes  18.7 Gbits/sec    0             sender
[  5]   0.00-10.00  sec  21.8 GBytes  18.7 Gbits/sec                  receiver
[  7]   0.00-10.00  sec  21.8 GBytes  18.7 Gbits/sec    0             sender
[  7]   0.00-10.00  sec  21.8 GBytes  18.7 Gbits/sec                  receiver
[SUM]   0.00-10.00  sec  43.6 GBytes  37.5 Gbits/sec    0             sender
[SUM]   0.00-10.00  sec  43.6 GBytes  37.5 Gbits/sec                  receiver

I have also confirmed HW = yes is on for all the qsfpplus ports as you can see below:

 #     INTERFACE                                                        BRIDGE                                                        HW  PVID PRIORITY  PATH-COST INTERNAL-PATH-COST    HORIZON
53   H qsfpplus1-1                                                      bridge                                                        yes  110     0x80         10                 10       none
54 I H qsfpplus1-2                                                      bridge                                                        yes  110     0x80         10                 10       none
55 I H qsfpplus1-3                                                      bridge                                                        yes  110     0x80         10                 10       none
56 I H qsfpplus1-4                                                      bridge                                                        yes  110     0x80         10                 10       none
57   H qsfpplus2-1                                                      bridge                                                        yes  110     0x80         10                 10       none
58 I H qsfpplus2-2                                                      bridge                                                        yes  110     0x80         10                 10       none
59 I H qsfpplus2-3                                                      bridge                                                        yes  110     0x80         10                 10       none
60 I H qsfpplus2-4                                                      bridge                                                        yes  110     0x80         10                 10       none

CRS354.txt (4.66 KB)

A post was split to a new topic: 10/40Gb strange things