| Keith C. Perry on 24 Aug 2016 12:27:46 -0700 |
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| Re: [PLUG] RAID6 or RAID5+HS? |
That's not quite right. A NUMA system is essentially what SMP used to be. Its multiple processors (which have multiple cores) so for instance if you type... numactl --hardware On your system, you'll probably get something like, available: 1 nodes (0) node 0 cpus: 0 1 2 3 node 0 size: 11916 MB node 0 free: 414 MB node distances: node 0 0: 10 This is my ultrabook- its a Core i7 and has that hyperthreading crap is turned on so I see 1 node an 4 cores. If hyperthreading was off, I would see 2 cores. Now, lets check a Supermicro 2-way system with the same command... available: 2 nodes (0-1) node 0 cpus: 0 1 2 3 4 5 12 13 14 15 16 17 node 0 size: 24156 MB node 0 free: 20087 MB node 1 cpus: 6 7 8 9 10 11 18 19 20 21 22 23 node 1 size: 24238 MB node 1 free: 23970 MB node distances: node 0 1 0: 10 21 1: 21 10 What you see here is a Xeon with hyperthreading on. 6 core, 12 threads. Each one those CPUs is "attached" to 24Gb of RAM (max is probably 64Gb... 8 slots by 8Gb since this system is older). So, you can use this as a 24 core, 48Gb system or 2 12 core, 24Gb systems. It depends on your NUMA configuration. For reference: https://www.kernel.org/doc/Documentation/vm/numa https://www.kernel.org/doc/Documentation/kernel-parameters.txt https://www.kernel.org/doc/Documentation/x86/x86_64/fake-numa-for-cpusets ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Keith C. Perry, MS E.E. Owner, DAO Technologies LLC (O) +1.215.525.4165 x2033 (M) +1.215.432.5167 www.daotechnologies.com ----- Original Message ----- From: "Rich Freeman" <r-plug@thefreemanclan.net> To: "Philadelphia Linux User's Group Discussion List" <plug@lists.phillylinux.org> Sent: Wednesday, August 24, 2016 2:46:59 PM Subject: Re: [PLUG] RAID6 or RAID5+HS? On Wed, Aug 24, 2016 at 2:36 PM, Keith C. Perry <kperry@daotechnologies.com> wrote: > > Sound like the its just a matter of vendor not making 2 way or 4 way NUMA boards for consumer chips. Could be some other details we're missing too. > Actually, what I'm saying is that if you have an AMD chip in the PC you're typing this on, it IS a NUMA system if it has multiple cores. Regions of RAM will operate more or less quickly depending on which core accesses them. AMD chips tend to be NUMA by design. If that has changed I'm all ears, but you don't need a special motherboard to have a NUMA AMD64 system. You basically don't get a choice in it. If the kernel doesn't take that into account, then software will run slightly slower since it might run on cores that aren't optimized for the region of memory their data is stored in. -- Rich ___________________________________________________________________________ Philadelphia Linux Users Group -- http://www.phillylinux.org Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug ___________________________________________________________________________ Philadelphia Linux Users Group -- http://www.phillylinux.org Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug