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Document section:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_for_Real_Time/7/html/Tuning_Guide/Interrupt_and_process_binding.html

Subsection:
Procedure 2.4. Excluding CPUs from IRQ Balancing

Starting on RHEL 7.2, when using the isolcpus= kernel parameter, and
the IRQBALANCE_BANNED_CPUS is not set on /etc/sysconfig/irqbalance config
file, the irqbalance will automatically avoid IRQs on CPUs isolated via
isolcpus=.

Please, add a note about this behavior in the section:
 - Procedure 2.4. Excluding CPUs from IRQ Balancing

For example:

"NOTE: The irqbalance will automatically avoid IRQs on CPUs isolated via
isolcpus= kernel parameter if IRQBALANCE_BANNED_CPUS is not set"

Done in git, thanks for the heads up!

http://git.app.eng.bos.redhat.com/git/doc-Red_Hat_Enterprise_Linux-7-Realtime_Tuning_Guide.git/commit/?id=9e500b6422bafc10e0e4ce5778ade5131c99e4bd

(The note is outside the procedure block because (apparently) you can't use a note after you've started with steps.)