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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 -XX:+UseNUMA 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?

like image 772
vsminkov Avatar asked Sep 13 '16 11:09

vsminkov


1 Answers

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

like image 190
apangin Avatar answered Nov 04 '22 13:11

apangin