[Xen-users] XenProject.org Q&A: Why do DomU interrupt numbers start at 245?

[Russ Pavlicek <russell.pavlicek@xxxxxxxxxxxxxx>]

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
... ...

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users