these might answer your question https://bugzilla.novell.com/show_bug.cgi?id=244916
The 2nd one states:
"you have a single socket system where the cores share the L2 cache.
For these systems dynamic irq balancing isn't really the right
approach; they don't really have need. What irqbalance 0.55 will do is
set up a static spread of the interrupts over the 2 cores, and then
exit to avoid wasting CPU cycles. This should provide the best
possible behavior on your system..."
So it seems OK to run the service also for dual core single socket systems, as
all it will do ( and does for me ) is setting up a statistical distribution and