[bt848]

So why is it important to have a multisocket NUMA machine? Why not just save yourself a lot of hassle by having one socket? I know that the previous generation AMD machine had unavoidable NUMA but the new one doesn't.

[loeg]

This talk is about Zen+ Epyc, not Zen2 (which is where the non-cache memory gets uniform). I don't know if they have release quality Epyc 7003 (Zen2) samples available yet, and if they do, NFLX probably isn't allowed to publish benchmarks about them. There's almost certainly still some value in their existing NUMA work even on Zen2, as things like L1/L2/L3 cache have locality even if memory and PCIe does not.

Pretty sure Intel single socket of this generation is totally non-viable for this workload due to lack of PCIe lanes. Maybe viable when Intel gets gen4 PCIe.

[bt848]

Skylake-X has 44 PCI 3.0 lanes, that's 352GT/s or about 345gbps application bandwidth. It's certainly more than enough to push 100gbps from disk to net. These guys are pushing 200gbps, but they're doing it with two CPUs, two sets of NVMe devices, and two NICs, and a bunch of hacks to make the operating system pretend all this stuff is not in the same box. It seems way more straight-forward to me if they had made it all be actually NOT in the same box!

[drewg123]

I've run this particular AMD system in 3 ways: - Non-NUMA - 2 nodes per socket - 4 nodes per socket

The 4NPS gives the best performance, followed by 2NPS, followed by non-NUMA. This surprised me as well.

[baolongtrann]

It's money. Having a two-socket machine instead 2 one-socket machines, even when performance is only 80%, is saving both OPex and CAPex.

[dragontamer]

Communication over DDR4 is way faster than communication over PCIe Ethernet. Even 40Gbit is slow compared to RAM.

[bt848]

Maybe but this post is about making the two sides of the computer NOT communicate.

[kylek]

Density/power/cooling are real constraints when you aren't 100% bought-in to the cloud.

[toast0]

One bigger host meams less management overhead. (see other comments about being u willing to run multiple ips and what not)

It may be a bit early to have a presentation from the latest Epyc processors. Most of the work was likely done with previous processors, but their slides said their AMD boxes are single socket.

[o-__-o]

Something something performant concurrency