[rescue] New Origin 3400 in Ottawa

[Jonathan Patschke]

On Mon, 27 Jan 2020, r.stricklin wrote:

> Sure, but a lot of these new systems are actually NUMA architectures under the
> covers (I'm not totally up to date on all the various vendor's models, but
> certainly there's been a nonzero number of the multi-socket x86_64 proliants
> we've ordered in the last half decade that have been NUMA - not sure about
> cache-coherent vs. not though... I think, not).

Multi-socket Xeon systems are ccNUMA since Haswell (using MESIF), and
multi-socket AMD systems have been cache-coherent long before (1st- or
2nd-generation Opteron, using MOESI).

Single-socket AMD Epyc systems even have to run cache-coherent because of
how separate the individual complexes are on the multi-chip module.  Even
single-socket AMD Naples systems can slice the hardware into 4 NUMA nodes
for reduced I/O latency.  The Rome systems I've seen have much better
worst-case latency and tend to run in a single node for single-socket
setups.

NUMA without cache-coherency has pretty limited applications.  Outside of
ARM, it's effectively implied anymore.

-- 
Jonathan Patschke   |   "The more you mess with it, the more you're
Austin, TX          |    going to *have* to mess with it."
USA                 |                            --Gearhead Proverb