There is a numerous articles regarding benefits of JVM NUMA-aware allocators. However I could not find information about what performance impact may cause
# numactl --hardware
available: 1 nodes (0)
node 0 cpus: 0 1 2 3
node 0 size: 32060 MB
node 0 free: 7770 MB
-XX:+UseNUMA does no harm in these cases.
HotSpot JVM automatically turns off the flag when run on a single node (the source).