On 28/03/2012 16:57, Tyson Whitehead wrote:
On March 28, 2012 04:41:16 Simon Marlow wrote:
Sure. Do you have a NUMA machine to test on?
My understanding is non-NUMA machines went away when the AMD and Intel moved away from frontside buses (FSB) and integrated the memory controllers on die.
Intel is more recent to this game. I believe AMD's last non-NUMA machines where the Athalon XP series and Intel's the Core 2 series.
An easy way to see what you've got is to see what 'numactl --hardware' says. If the node distance matrix is not uniform, you have NUMA hardware.
As an example, on a 8 socket Opteron machine (32 cores) you get
$ numactl --hardware available: 8 nodes (0-7) node 0 size: 16140 MB node 0 free: 3670 MB node 1 size: 16160 MB node 1 free: 3472 MB node 2 size: 16160 MB node 2 free: 4749 MB node 3 size: 16160 MB node 3 free: 4542 MB node 4 size: 16160 MB node 4 free: 3110 MB node 5 size: 16160 MB node 5 free: 1963 MB node 6 size: 16160 MB node 6 free: 1715 MB node 7 size: 16160 MB node 7 free: 2862 MB node distances: node 0 1 2 3 4 5 6 7 0: 10 20 20 20 20 20 20 20 1: 20 10 20 20 20 20 20 20 2: 20 20 10 20 20 20 20 20 3: 20 20 20 10 20 20 20 20 4: 20 20 20 20 10 20 20 20 5: 20 20 20 20 20 10 20 20 6: 20 20 20 20 20 20 10 20 7: 20 20 20 20 20 20 20 10
Well, you learn something new every day! On the new 32-core Opteron box we have here: available: 8 nodes (0-7) node 0 cpus: 0 4 8 12 node 0 size: 8182 MB node 0 free: 1994 MB node 1 cpus: 16 20 24 28 node 1 size: 8192 MB node 1 free: 2783 MB node 2 cpus: 3 7 11 15 node 2 size: 8192 MB node 2 free: 2961 MB node 3 cpus: 19 23 27 31 node 3 size: 8192 MB node 3 free: 5359 MB node 4 cpus: 2 6 10 14 node 4 size: 8192 MB node 4 free: 3030 MB node 5 cpus: 18 22 26 30 node 5 size: 8192 MB node 5 free: 4667 MB node 6 cpus: 1 5 9 13 node 6 size: 8192 MB node 6 free: 3240 MB node 7 cpus: 17 21 25 29 node 7 size: 8192 MB node 7 free: 4031 MB node distances: node 0 1 2 3 4 5 6 7 0: 10 16 16 22 16 22 16 22 1: 16 10 16 22 22 16 22 16 2: 16 16 10 16 16 16 16 22 3: 22 22 16 10 16 16 22 16 4: 16 22 16 16 10 16 16 16 5: 22 16 16 16 16 10 22 22 6: 16 22 16 22 16 22 10 16 7: 22 16 22 16 16 22 16 10 The node distances on this box are less uniform than yours. Cheers, Simon