How do I know if my server has NUMA?

Question

Hopping from Java Garbage Collection, I came across JVM settings for NUMA. Curiously I wanted to check if my CentOS server has NUMA capabilities or not. Is there a *ix command or utility that could grab this info?

Answer 1

I'm no expert here, but here's something:

Box 1, no NUMA:

~$ dmesg | grep -i numa [    0.000000] No NUMA configuration found 

Box 2, some NUMA:

~$ dmesg | grep -i numa [    0.000000] NUMA: Initialized distance table, cnt=8 [    0.000000] NUMA: Node 4 [0,80000000) + [100000000,280000000) -> [0,280000000) 

Answer 2

I think this previous question is similar: How to confirm NUMA?

In particular, you can review the NUMA man page here: http://man7.org/linux/man-pages/man7/numa.7.html

And from there you'll see:

$ find /proc -name numa_maps
/proc/1/task/1/numa_maps
/proc/1/numa_maps
/proc/2/task/2/numa_maps
/proc/2/numa_maps
/proc/3/task/3/numa_maps
[etc if you have numa]

And you can get more detail like so:

$ grep NUMA=y /boot/config-`uname -r`
CONFIG_NUMA=y
CONFIG_K8_NUMA=y
CONFIG_X86_64_ACPI_NUMA=y
CONFIG_ACPI_NUMA=y

$ numactl --hardware
available: 2 nodes (0-1)
node 0 size: 18156 MB
node 0 free: 9053 MB
node 1 size: 18180 MB
node 1 free: 6853 MB
node distances:
node   0   1
  0:  10  20
  1:  20  10