IRQ balance behavior different in newer RHEL kernels

Issue

• We have an irqbalance config that works on 2.6.32-279.22.1.el6.x86_64, but is failing on 2.6.32-358.6.1.el6.x86_64
• Here is the config from each:

[root@mybox tmp]# grep -v ^# /etc/sysconfig/irqbalance
ONESHOT=yes
IRQ_AFFINITY_MASK=FFFC

• Both are 16-core, 2 socket machines.