FreeBSD NUMA domain memory monitor
$ numastat
DOMAIN ACTIVE INACTIVE LAUNDRY FREE
-------- -------- -------- -------- --------
0 1.91G 18.93G 4.91G 42.92G
1 1.76G 521.39M 5.24G 9.90G
-------- -------- -------- -------- --------
0 1.90G 18.93G 4.91G 42.91G
1 1.76G 521.50M 5.24G 2.20G
To quote Wikipedia:
Non-uniform memory access (NUMA) is a computer memory design used in multiprocessing, where the memory access time depends on the memory location relative to the processor
Operating systems usually make some effort to allocate resources in a NUMA-aware fashion in order to maximise performance, and FreeBSD is no different.
numastat formats and displays the size of per-NUMA-domain page queues
exported through the vm.domain sysctl hierarchy so you can monitor how
memory allocations are balanced (or unbalanced, as in the above example)
across domains.