Interrupts are confined to only CPU0 Core why?

Question

Why interrupts are confined to CPU0, rather than using other cores that are available? Only for LOC: I could see the interrupts being distributed to other cores why it's not happening for eth0 and eth1?

           CPU0       CPU1       CPU2       CPU3
  0: 3860081907          0          0          0    IO-APIC-edge  timer
  1:         20          0          0          0    IO-APIC-edge  i8042
  6:          5          0          0          0    IO-APIC-edge  floppy
  7:          0          0          0          0    IO-APIC-edge  parport0
  8:          0          0          0          0    IO-APIC-edge  rtc
  9:          0          0          0          0   IO-APIC-level  acpi
 12:        240          0          0          0    IO-APIC-edge  i8042
 14:   11651412          0          0          0    IO-APIC-edge  ide0
 51:   63756555          0          0          0   IO-APIC-level  ioc0
 59:          1          0          0          0   IO-APIC-level  vmci
 67:   20176527          0          0          0   IO-APIC-level  eth0
 75:   98414043          0          0          0   IO-APIC-level  eth1
NMI:          0          0          0          0
LOC: 3887753782 3887746069 3887748988 3887748054
ERR:          0
MIS:          0

I checked smp_affinity file for eth0, but I couldn't make out much from it.

cat /proc/irq/67/smp_affinity
00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000001

I'm not sure what you're asking. Are you experiencing performance issues? — Katherine Villyard, Jan 09 '14 at 03:43
@KatherineVillyard No i was a bit curious why all my other CPU cores have 0 count other than CPU0. Is there any specific reason? — user204857, Jan 09 '14 at 03:46
@ewwhite Thanks for pointing that out. i was not aware of irqbalance, did a bit googling on it. Once again thanks — user204857, Jan 09 '14 at 08:34

score 2 · Accepted Answer · answered Jan 09 '14 at 08:42

2

You may want to enable irqbalance if it is not currently running on the system.

answered Jan 09 '14 at 08:42

ewwhite

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Interrupts are confined to only CPU0 Core why?

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