我正在测试与在 Bananpi M2+ 单板计算机（Debian，5.1.1-BPI-Kernel #1 SM）上运行的 iperf 服务器（iperf 版本 2.0.13（2019 年 1 月 21 日）pthreads）的连接。对于不同的目标带宽，我观察到不同的数据包丢失率。对于非常低和非常高的目标带宽设置（低于 1%），丢失的数据包数量很少。然而，对于中等值，丢失的数据包数量非常高（例如，在 400 Mbps 时丢失了 29% 的数据包）。什么可能导致这种行为？（详细结果见下文）。这是测试网络中发生的唯一通信（因此丢失必须发生在目标端）。
我已经尝试调整 UDP 套接字的大小，但并没有改善结果。
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size: 3.81 MByte (WARNING: requested 1.91 MByte)
------------------------------------------------------------
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 37950
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 3] 0.0-10.0 sec 11.9 MBytes 10.0 Mbits/sec 0.195 ms 0/ 8504 (0%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 32833
[ 4] 0.0-10.0 sec 118 MBytes 98.9 Mbits/sec 0.306 ms 571/85034 (0.67%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 56833
[ 3] 0.0-10.0 sec 344 MBytes 288 Mbits/sec 0.053 ms 9951/255103 (3.9%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 51751
[ 4] 0.0-10.0 sec 337 MBytes 283 Mbits/sec 0.026 ms 99684/340136 (29%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 53331
[ 3] 0.0-10.0 sec 512 MBytes 429 Mbits/sec 0.018 ms 60157/425171 (14%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 35110
[ 4] 0.0-10.0 sec 832 MBytes 698 Mbits/sec 0.014 ms 1860/595239 (0.31%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 52002
[ 3] 0.0-10.0 sec 1.04 GBytes 897 Mbits/sec 0.013 ms 2895/765308 (0.38%)
更新 对于 400 Mbps，当我以默认优先级运行 iperf 作为进程时，我得到以下结果：
pi@bpi2:~$ iperf -s -u
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size: 25.0 MByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 44269
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 3] 0.0-10.0 sec 379 MBytes 318 Mbits/sec 0.030 ms 69509/340136 (20%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 53115
[ 4] 0.0-10.0 sec 463 MBytes 389 Mbits/sec 0.022 ms 9715/340137 (2.9%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 39077
[ 3] 0.0-10.0 sec 431 MBytes 362 Mbits/sec 0.031 ms 32537/340136 (9.6%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 47676
[ 4] 0.0-10.0 sec 363 MBytes 305 Mbits/sec 0.029 ms 81019/340136 (24%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 52106
[ 3] 0.0-10.0 sec 407 MBytes 341 Mbits/sec 0.030 ms 49872/340136 (15%)
当我设置最高优先级时：
pi@bpi2:~$ sudo ionice -c 1 -n 0 nice -n -20 iperf -s -u
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size: 25.0 MByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 59056
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 3] 0.0-10.0 sec 460 MBytes 386 Mbits/sec 0.022 ms 11665/340137 (3.4%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 54558
[ 4] 0.0-10.0 sec 450 MBytes 378 Mbits/sec 0.039 ms 18941/340137 (5.6%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 34361
[ 3] 0.0-10.0 sec 437 MBytes 366 Mbits/sec 0.029 ms 28662/340137 (8.4%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 47201
[ 4] 0.0-10.0 sec 474 MBytes 398 Mbits/sec 0.033 ms 1953/340136 (0.57%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 34809
[ 3] 0.0-10.0 sec 442 MBytes 371 Mbits/sec 0.030 ms 24886/340136 (7.3%)
[ 4] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 54412
[ 4] 0.0-10.0 sec 429 MBytes 360 Mbits/sec 0.037 ms 34388/340138 (10%)
[ 3] local 192.168.1.11 port 5001 connected with 192.168.1.201 port 55946
[ 3] 0.0-10.0 sec 446 MBytes 374 Mbits/sec 0.034 ms 22341/340136 (6.6%)
答案1
与此同时，我自己也找到了解决方案。iperf 出现这种奇怪行为的原因不是应用程序本身，而是 NIC 驱动程序出现故障（很可能是 GbE 延迟设置不正确导致的）。
有帮助的是完全重新安装操作系统并切换到具有正确驱动程序集的 Armbian 4.19。我设法在 armbian 论坛中找到了解决方案，它为任何对全志 h3 SoC 感兴趣的人提供了非常广泛的信息（就像我在 BananaPi M2+ 中使用的一样，还有许多其他产品）。