Q. How do I list all IRQs currently used under CentOS Linux?
A.. There is a file called /proc/interrupts. The proc filesystem is a pseudo filesystem which is used as an interface to kernel data structures. It is commonly mounted at /proc.
This is used to record the number of interrupts per each IRQ on (at least) the i386 architecture. Very easy to read formatting, done in ASCII.
Display /proc/interrupts
Use cat or less command:
$ cat /proc/interrupts
Output:
CPU0 CPU1 CPU2 CPU3 0: 187 0 0 0 IO-APIC-edge timer 1: 39922 0 0 0 IO-APIC-edge i8042 7: 0 0 0 0 IO-APIC-edge parport0 8: 4 0 0 0 IO-APIC-edge rtc 9: 1 0 0 0 IO-APIC-fasteoi acpi 12: 846774 0 0 0 IO-APIC-edge i8042 14: 105048 0 0 0 IO-APIC-edge libata 15: 0 0 0 0 IO-APIC-edge libata 16: 1069722 0 0 0 IO-APIC-fasteoi libata, uhci_hcd:usb4, nvidia 17: 105382 0 0 0 IO-APIC-fasteoi eth0 18: 83040 0 0 0 IO-APIC-fasteoi uhci_hcd:usb2, libata 19: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb1, ehci_hcd:usb5 20: 474168 0 0 0 IO-APIC-fasteoi uhci_hcd:usb3, ohci1394, ra0 21: 10117 0 0 0 IO-APIC-fasteoi bttv0 22: 594327 0 0 0 IO-APIC-fasteoi HDA Intel NMI: 0 0 0 0 LOC: 1754492 1545836 2085855 1878596 ERR: 0 MIS: 0