今天新拿到瑞芯微RV1126的开发板，是双网口双百兆接口，内存为2G，emmc flash为32G，一开始无法分辨物理接口和系统的eth是对应的，遂想用ethtool工具来查看网速，发现：
ethtool eth0 # 可以正常返回网络相关信息及当前连接速率root@aioter:~# ethtool eth0
Settings for eth0:Supported ports: [ TP AUI BNC MII FIBRE ]Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supported pause frame use: Symmetric Receive-onlySupports auto-negotiation: YesSupported FEC modes: Not reportedAdvertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: NoAdvertised auto-negotiation: YesAdvertised FEC modes: Not reportedLink partner advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Link partner advertised pause frame use: Symmetric Receive-onlyLink partner advertised auto-negotiation: YesLink partner advertised FEC modes: Not reportedSpeed: 1000Mb/sDuplex: FullPort: MIIPHYAD: 0Transceiver: internalAuto-negotiation: onSupports Wake-on: ugWake-on: dCurrent message level: 0x0000003f (63)drv probe link timer ifdown ifupLink detected: yesethtool eth1 # 不能正常显示当前速率，只显示为：current message level ：0x00000007然后经过查询资料解答为:
因为ethtool通常用于查询物理网络接口（如以太网接口）的速率和其他属性，而USB转换器通常被视为虚拟接口。
那么如果要查询usb转换后的网速呢?
通过查看sysfs中的信息
ls /sys/class/net/
cat /sys/class/net/<interface_name>/speed
请确保替换命令中的 <interface_name> 为你USB转换的网络适配器的名称。
如果这些方法仍无法解决问题，请检查USB转换器制造商的文档，以确定如何查询其速率信息。
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