Russ Pavlicek
2014-Nov-17 15:26 UTC
XenProject.org Q&A: Why do DomU interrupt numbers start at 245?
On the XenProject.org Q&A system this question was asked. I have no idea why it looks this way. Can someone explain why this happens? Q&A user 'tonysuo' asks: When I print the interrupt lines in Guest OS like below: root@centos65-pv-1 # cat /proc/interrupts CPU0 245: 432 xen-dyn-event eth0 246: 5747 xen-dyn-event blkif 247: 0 xen-dyn-event vkbd 248: 1 xen-dyn-event 249: 429 xen-dyn-event vfb 250: 407 xen-dyn-event xenbus 251: 0 xen-percpu-ipi callfuncsingle0 252: 0 xen-percpu-virq debug0 253: 0 xen-percpu-ipi callfunc0 254: 0 xen-percpu-ipi resched0 255: 20175 xen-percpu-virq timer0 NMI: 0 Non-maskable interrupts LOC: 0 Local timer interrupts SPU: 0 Spurious interrupts PMI: 0 Performance monitoring interrupts IWI: 0 IRQ work interrupts RES: 0 Rescheduling interrupts CAL: 0 Function call interrupts TLB: 0 TLB shootdowns TRM: 0 Thermal event interrupts THR: 0 Threshold APIC interrupts MCE: 0 Machine check exceptions MCP: 0 Machine check polls ERR: 0 MIS: 0 my question is why the interrupt line number start from 245? Here is the interrupt line in physical machine. You can see it start from 0. # cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7 0: 128 0 0 0 0 0 0 0 IO-APIC-edge timer 3: 2 0 0 0 0 0 0 0 IO-APIC-edge 4: 2 0 0 0 0 0 0 0 IO-APIC-edge 8: 1 0 0 0 0 0 0 0 IO-APIC-edge rtc0 9: 0 0 0 0 0 0 0 0 IO-APIC-fasteoi acpi 20: 29 0 0 0 0 0 21 0 IO-APIC-fasteoi ehci_hcd:usb1 23: 29 0 0 0 21 0 0 0 IO-APIC-fasteoi ehci_hcd:usb2 24: 20683 0 0 0 0 0 0 0 HPET_MSI-edge hpet2 25: 0 0 0 0 0 0 0 0 HPET_MSI-edge hpet3 26: 0 0 0 0 0 0 0 0 HPET_MSI-edge hpet4 27: 0 0 0 0 0 0 0 0 HPET_MSI-edge hpet5 28: 0 0 0 0 0 0 0 0 HPET_MSI-edge ... ...