Manually balance IRQs or use irqbalance?
A good discussion of when manual IRQ balancing is and is not appropriate came up on the page where we posted a tech brief on the subject:
https://access.redhat.com/knowledge/techbriefs/optimizing-red-hat-enterprise-linux-performance-tuning-irq-affinity
If you have had success manually pinning IRQ interrupts to specific processors (or tried it and decided you didn't get the performance improvements you had hoped), feel free to contribute your experiences here.