ubuntu - Linux系统上, "lo(本地还回)"网卡的性能取决于什么?

Question

我在笔记本上, Ubuntu系统, cpu(酷睿i5)大概占用50%, 用iperf测了几次, 速度为 38~40Gbits/sec

xxx@xxx:~$ iperf -c 127.0.0.1
------------------------------------------------------------
Client connecting to 127.0.0.1, TCP port 5001
TCP window size: 2.50 MByte (default)
------------------------------------------------------------
[  3] local 127.0.0.1 port 41856 connected with 127.0.0.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  47.2 GBytes  40.6 Gbits/sec

Answer 1

If you use localhost as both host and client, iperf does not use the network card, but directly swaps memory, so the speed here reflects your memory access speed. Here, you transferred a total of 47.2G bytes in 10 seconds, so the speed is 4.72GB/second, which is your memory speed.