LOCAL_CPUS vs INTR_CPUS

[K. Macy]

I haven't been able to get an answer out of the usual suspects so I
thought I'd ask here.

In reference to:
https://github.com/freebsd/freebsd/compare/master...bsdjhb:numa_bus_get_cpus


The LOCAL_CPUS option will return the cpuset corresponding to the NUMA
(_pxm) domain id of a given device. INTR_CPUS can narrow that further.
However, in this particular branch INTR_CPUS will only ever return the
value given by LOCAL_CPUS. When and where would this come in to
effect? Do the new Haswells have cores in the same memory domain but
with non-uniform access to the PCIe bus?

Thanks.