vsminkov vsminkov - 1 month ago 9x
Java Question

How does -XX:+UseNUMA affects JVM performance for systems with only one node?

There is a numerous articles regarding benefits of JVM NUMA-aware allocators. However I could not find information about what performance impact may cause

flag for single-node topologies like

# numactl --hardware
available: 1 nodes (0)
node 0 cpus: 0 1 2 3
node 0 size: 32060 MB
node 0 free: 7770 MB
node distances:
node 0
0: 10

It seems that this is a kind of corner case and there is no real profit in enabling flag. If so is there any drawbacks may be caused by enabling it?


-XX:+UseNUMA does no harm in these cases.
HotSpot JVM automatically turns off the flag when run on a single node (the source).