[wmantly]

It has to do with memory. In server grade computers, each socket has memory local slots that it can read and write to very fast. Read this: https://en.wikipedia.org/wiki/Non-uniform_memory_access

[Kubuxu]

It is already the case with Thread Ripper processors. They have multiple NUMA nodes inside one socket.

[Yizahi]

Exactly the same case as single die Xeon architecture with 2 separate rings inside with different memory modules attached to each ring - https://images.anandtech.com/doci/9193/HaswellEPHCCdie_575px...

[devttyeu]

It actually presents itself to the system as a single node:

On a TR 1920x system:

  $ numactl --hardware
  available: 1 nodes (0)
  node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
  node 0 size: 32107 MB
  node 0 free: 20738 MB
  node distances:
  node   0 
    0:  10

[dragontamer]

Threadripper ships in single-node interleaved memory by default, at least on my motherboard. This increases latency but doubles bandwidth (because now all 4-sticks of RAM are interleaved).

There's a BIOS setting. I personally enabled it using AMD's "Ryzen Master" program to setup NUMA mode (aka: "Local" mode in Ryzen Master).

[bpye]

I'm pretty sure you can change that, it should be a BIOS option [1].

[1] - https://www.anandtech.com/show/11697/the-amd-ryzen-threadrip...

[wmantly]

This is from a 4 socket Xeon E7-4860 with 64 ram slots(16 in use)

  e7-4860:~ Mon Jun 11
  03:06 PM william$ numactl --hardware
  available: 4 nodes (0-3)
  node 0 cpus: 0 1 2 3 4 5 6 7 8 9 40 41 42 43 44 45 46 47 48 49
  node 0 size: 16035 MB
  node 0 free: 1306 MB
  node 1 cpus: 10 11 12 13 14 15 16 17 18 19 50 51 52 53 54 55 56 57 58 59
  node 1 size: 16125 MB
  node 1 free: 3237 MB
  node 2 cpus: 20 21 22 23 24 25 26 27 28 29 60 61 62 63 64 65 66 67 68 69
  node 2 size: 16125 MB
  node 2 free: 11004 MB
  node 3 cpus: 30 31 32 33 34 35 36 37 38 39 70 71 72 73 74 75 76 77 78 79
  node 3 size: 16123 MB
  node 3 free: 12044 MB
  node distances:
  node   0   1   2   3 
    0:  10  20  20  20 
    1:  20  10  20  20 
    2:  20  20  10  20 
    3:  20  20  20  10

The chart at the bottom of the output is the weight for accessing a memory pool from a CPU socket. This is the most important part of the output.

On this server, CPU socket 0 is hardwired to ram slots 0-15

CPU 1 to ram slots 16-31

CPU 2 to ram slots 32-47

CPU 3 to ram slots 48-63

If CPU 0 wanted to read something outside of its local ram slots, it would have execute something on CPU n, then copy that segment to its local ram group.

[washadjeffmad]

That's not normal. Is it set to Channel/NUMA mode?

[throwaway2048]

windows is spectacularly poor at dealing with NUMA CPUS so threadripper is not displayed to the OS as NUMA.

[dragontamer]

Please don't say things that are obviously untrue.

I've got a Threadripper 1950x and got 2x NUMA nodes. You gotta enable a BIOS setting.

Second: "$ numactl --hardware " is a Linux command. The Windows equivalent is coreinfo.

https://docs.microsoft.com/en-us/sysinternals/downloads/core...

[pixelpoet]

Really? I've been thinking of getting a TR for some NUMA coding experience, and if Windows can't see that then it really sucks.

[my123]

It's togglable in the BIOS/UEFI.