[Ilugc] 2.6 SMP kernel -- dual core opteron processor -- irqbalance(?) - only one CPU busy always

[Balu manyam]

hey gurus -- i have a HP server with 4*dual core AMD opteron processors
running 2.6.9-42  SMP kernel   -- one of my DBAs complained of  poor
performance while running an SQL query -- now when  I check the 'mpstat -P
ALL  5 '  o/p - I see that CPU 0 is completely busy (idle 0%)  most of the
time -- while the other CPUs are close to 99% idle -- I did a cat
/proc/interrupts  I see that CPU0 is indeed having high values corresponding
to ethernet devices , other PCI devices , RAID controller  and the timer as
well --- I also checked that we are running irqbalance daemon and please
note that we are running the kernel with noapic option -- not sure if that
matters  at all

any inputs you may render are higlhly appreciated

Thanks!!