Networking 10G链路的netcat和iperf结果存在巨大差异

看到netcat和iperf结果之间的巨大差异，我感到困惑。我有10克链接连接我的服务器和客户端。iperf的速度约为10Gb/s，但netcat的速度仅为280Mb/s。可能是什么错误

对于Iperf

服务器

iperf -s

nc -v -v -l -n 2222 >/dev/null

客户

iperf -c 172.79.56.27 -i1 -t 10

time dd if=/dev/zero | nc -v -v -n 172.79.56.27 2222


Connection to 172.79.56.27 2222 port [tcp/*] succeeded!
^C6454690+0 records in
 6454690+0 records out
 3304801280 bytes (3.3 GB) copied, 11.4463 s, 289 MB/s


real    0m11.449s
user    0m6.868s
sys 0m15.372s

结果:

Client connecting to 172.79.56.27, TCP port 5001

TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  3] local 172.79.56.28 port 46058 connected with 172.79.56.27 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 1.0 sec  1.07 GBytes  9.23 Gbits/sec
[  3]  1.0- 2.0 sec  1.09 GBytes  9.35 Gbits/sec
[  3]  2.0- 3.0 sec  1.09 GBytes  9.35 Gbits/sec
[  3]  3.0- 4.0 sec  1.09 GBytes  9.35 Gbits/sec
[  3]  4.0- 5.0 sec  1.09 GBytes  9.36 Gbits/sec
[  3]  5.0- 6.0 sec  1.09 GBytes  9.35 Gbits/sec
[  3]  6.0- 7.0 sec  1.09 GBytes  9.36 Gbits/sec
[  3]  7.0- 8.0 sec  1.09 GBytes  9.35 Gbits/sec
[  3]  8.0- 9.0 sec  1.09 GBytes  9.36 Gbits/sec
[  3]  9.0-10.0 sec  1.09 GBytes  9.35 Gbits/sec
[  3]  0.0-10.0 sec  10.9 GBytes  9.34 Gbits/sec

对于netcat

服务器

iperf -s

nc -v -v -l -n 2222 >/dev/null

客户

iperf -c 172.79.56.27 -i1 -t 10

time dd if=/dev/zero | nc -v -v -n 172.79.56.27 2222


Connection to 172.79.56.27 2222 port [tcp/*] succeeded!
^C6454690+0 records in
 6454690+0 records out
 3304801280 bytes (3.3 GB) copied, 11.4463 s, 289 MB/s


real    0m11.449s
user    0m6.868s
sys 0m15.372s

何志平先生:

再次运行netcat测试并在另一个窗口中观看htop。我打赌您会看到这里的瓶颈是dd reading/dev/zero的单线程。尝试与dd | netcat的'n'实例并行运行测试，其中'n'=系统中的#个内核。然后将所有并行运行的总带宽相加，以查看实际结果。（确保您在不同的端口上传输，并且让您的接收端运行多个线程，并在多个端口上侦听）