irq balancing question

Hello,list,

I want to change the irq bounding, but i can't.

[root@dy-xeon-1 irq]# cat 217/smp_affinity
f
[root@dy-xeon-1 irq]# echo 1 > 217/smp_affinity
[root@dy-xeon-1 irq]# cat 217/smp_affinity
f
[root@dy-xeon-1 irq]# /bin/echo 1 > 217/smp_affinity
[root@dy-xeon-1 irq]# cat 217/smp_affinity
f
[root@dy-xeon-1 irq]#

           CPU0       CPU1       CPU2       CPU3
  0:        117          0          0   17139594    IO-APIC-edge  timer
  8:          0          0          0       2842    IO-APIC-edge  rtc
  9:          0          0          0          0   IO-APIC-level  acpi
 14:          0          0          0    2701302    IO-APIC-edge  ide0
169:          0          0          0          0   IO-APIC-level
uhci_hcd:usb2
177:          0          0          0          0   IO-APIC-level
uhci_hcd:usb3
185:          0          0          0          0   IO-APIC-level
uhci_hcd:usb4
193:          0          0          0          0   IO-APIC-level
ehci_hcd:usb1
209:          0          0          0  211910641   IO-APIC-level  eth0
217:          0          0          0  494228730   IO-APIC-level  eth1
NMI:          0          0          0          0
LOC:   17139481   17139480   17139479   17139375
ERR:          0
MIS:          0

I have allready read all the documentation about this, and try to find
answer in google, but found nothing. :(

My kernel is 2.6.15-rc3, but with 2.6.14.2 is the same.
The system is dual xeon + HT.

My kernel config file is here:
http://download.netcenter.hu/bughunt/smp/config.txt


Thanks,
Janos