timer interrupt handled by CPU0 only

qmh524
2009-05-13T10:27:27Z

I have start irqbalance service. Why the timer interrupt only happend in CPU0
$ sudo service irqbalance status
irqbalance (pid 2390) is running...
$ cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3
0: 21487296 0 0 0 IO-APIC-edge timer
1: 3 0 0 0 IO-APIC-edge i8042
8: 1 0 0 0 IO-APIC-edge rtc
9: 0 0 0 0 IO-APIC-level acpi
12: 4 0 0 0 IO-APIC-edge i8042
74: 18 0 0 0 IO-APIC-level
uhci_hcd:usb1, uhci_hcd:usb3, ehci_hcd:usb4
82: 0 0 0 0 IO-APIC-level uhci_hcd:usb2
90: 1934 0 45886283 0 IO-APIC-level libata
98: 0 0 0 0 IO-APIC-level libata
106: 120 0 0 22824923 PCI-MSI eth0
169: 16933 0 9370507 0 IO-APIC-level ioc0
NMI: 43241 26776 33934 29946
LOC: 21487192 21487118 21487046 21486887
ERR: 0
MIS: 0
$ uname -a
Linux xxx 2.6.18-53.el5 #1 SMP Mon Nov 12 02:14:55 EST 2007 x86_64
x86_64 x86_64 GNU/Linux
$ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Xeon(R) CPU L5410 @ 2.33GHz
stepping : 6
cpu MHz : 2333.339
cache size : 6144 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm
constant_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr lahf_lm
bogomips : 4669.93
clflush size : 64
cache_alignment : 64
address sizes : 38 bits physical, 48 bits virtual
power management:

processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Xeon(R) CPU L5410 @ 2.33GHz
stepping : 6
cpu MHz : 2333.339
cache size : 6144 KB
physical id : 0
siblings : 4
core id : 1
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm
constant_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr lahf_lm
bogomips : 4666.62
clflush size : 64
cache_alignment : 64
address sizes : 38 bits physical, 48 bits virtual
power management:

processor : 2
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Xeon(R) CPU L5410 @ 2.33GHz
stepping : 6
cpu MHz : 2333.339
cache size : 6144 KB
physical id : 0
siblings : 4
core id : 2
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm
constant_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr lahf_lm
bogomips : 4666.69
clflush size : 64
cache_alignment : 64
address sizes : 38 bits physical, 48 bits virtual
power management:

processor : 3
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Xeon(R) CPU L5410 @ 2.33GHz
stepping : 6
cpu MHz : 2333.339
cache size : 6144 KB
physical id : 0
siblings : 4
core id : 3
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm
constant_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr lahf_lm
bogomips : 4666.54
clflush size : 64
cache_alignment : 64
address sizes : 38 bits physical, 48 bits virtual
power management:

$