スループットが低いIperf

環境

• ONTAP 9.11.1P8
• イペルフ

問題

• クラスタネットワークでiPerfスループットテストを実行しているときに、パフォーマンスが想定よりも低いことが確認されました。
• 問題を示すIperfの出力例：

[root@Cluster ~]# iperf3 -c <Dest Address> -T s1 -V
s1:  iperf 3.9
s1:  s1:  Linux sto-test-03 5.14.0-284.11.1.el9_2.x86_64 #1 SMP PREEMPT_DYNAMIC Tue May 9 05:49:00 EDT 2023 x86_64
Control connection MSS 8928
s1:  Time: Wed, 06 Sep 2023 11:49:54 GMT
s1:  Connecting to host <Destination> , port 5201
s1:     Cookie: 
s1:     TCP MSS: 8928 (default)
s1:  [  5] local <Source System> port 54628 connected to <Destination> port 5201
s1:  Starting Test: protocol: TCP, 1 streams, 131072 byte blocks, omitting 0 seconds, 10 second test, tos 0
s1:  [ ID] Interval       Transfer    Bitrate      Retr  Cwnd
s1:  [  5]   0.00-1.00   sec  1005 MBytes  8.43 Gbits/sec   68   1.40 MBytes
s1:  [  5]   1.00-2.00   sec  1.01 GBytes  8.68 Gbits/sec   54   2.02 MBytes
s1:  [  5]   2.00-3.00   sec   602 MBytes  5.05 Gbits/sec   0   2.71 MBytes
s1:  [  5]   3.00-4.00   sec   530 MBytes  4.45 Gbits/sec   0   2.98 MBytes
s1:  [  5]   4.00-5.00   sec   394 MBytes  3.30 Gbits/sec  104   1.74 MBytes
s1:  [  5]   5.00-6.00   sec   239 MBytes  2.00 Gbits/sec   0   2.12 MBytes
s1:  [  5]   6.00-7.00   sec  2.50 MBytes  21.0 Mbits/sec  0   1.93 MBytes
s1:  [  5]   7.00-8.00   sec   756 MBytes  6.34 Gbits/sec   36   2.43 MBytes
s1:  [  5]   8.00-9.00   sec  3.75 MBytes  31.4 Mbits/sec  0   2.43 Mbytes
s1:  [  5]   9.00-10.00  sec   579 MBytes  4.86 Gbits/sec   61   1.83 MBytes
s1:  - - - - - - - - - - - - - - - - - - - - - - - - -
s1:  Test Complete. Summary Results:
s1:  [ ID] Interval       Transfer    Bitrate      Retr
s1:  [  5]   0.00-10.00  sec  5.03 GBytes  4.32 Gbits/sec  323        sender
s1:  [  5]   0.00-10.03  sec  5.03 GBytes  4.30 Gbits/sec          receiver
s1:  CPU Utilization: local/sender 5.4% (0.3%u/5.1%s), remote/receiver 11.7% (0.1%u/11.7%s)
s1:  snd_tcp_congestion cubic
s1:  rcv_tcp_congestion cubic
s1:
s1:  iperf Done.