Directory in debugfs per Open Interface
If the debugfs feature is enabled in the kernel, the mlx5 driver maintains a subdirectory containing useful debug information for each open eth port inside /sys/kernel/debug/.
For the default network namespace, the subdirectory name is the name of the interface, like "eth8". When the network interface is moved to the non-default network namespaces, the interface name is followed by "@" and the port's PCI ID. For example, the subdirectory name would be "eth8@0000:af:00.3".