Retrieving irq number of a NIC

Question

I need to retrieve an interrupt number of interface by its' name as appears in ifconfig.

Is there some standard API to do it?

Answer 1

The interrupt number lives in sysfs. Look for the file /sys/class/net/[ethname]/device/irq. For example:

more /sys/class/net/*/device/irq
::::::::::::::
/sys/class/net/eth0/device/irq
::::::::::::::
30
::::::::::::::
/sys/class/net/eth1/device/irq
::::::::::::::
29

Answer 2

/sys/class/net/[ethname]/device/irq should legacy irq number, device may not be using legacy irq, it may be using msix.

check

$ ls /sys/class/net/eth0/device/msi_irqs/

or

$ grep eth0 /proc/interrupts